Dissertations / Theses on the topic 'Tuberculosis in cattle'

This thesis covers the formulation and analysis of a number of deterministic, continuous models of infection by a disease such as bovine tuberculosis in one species (essentially badgers) and in two mutually infective species (badgers and cattle). We examine the dynamics of the disease in each model and then consider the effects of the application of different badger culling strategies which have the objective of eliminating the disease in cattle.

Farm, cattle group and individual bovine risk factors for bovine tuberculosis (bTB) in cattle herds in the South West of England were explored. A cohort study using 148 well characterised cattle herds was conducted in SW England 2001-2004. The study was set up in areas affected by foot-and-mouth disease in 2001 and all farms were taking part in the Randomised Badger Culling Trial (RBCT). The use of a standard questionnaire and national data records from the skin intradermal cervical comparative tuberculin test (SICCT) and from the British Cattle Movement Service (BCMS) databases were combined. The two main statistical techniques used were survival analysis and multilevel logistic regression with random effects. Associations with the risk of herd breakdown with bTB were explored using survival analysis. The main factors associated with disclosure of reactor cattle were the purchase of cattle from markets and the storage of slurry and manure in close containment. In the investigation of the risk of an individual bovine animal becoming a reactor using multilevel logistic regression with random effects analysis, explanatory variables at herd, individual cattle and test levels, were explored. The potential exposure to reactor cattle in previous tests was the most significant finding as a risk for a bovine animal reacting at a current test. Only 9/19,027 cattle became reactors if they had not been exposed to a reactor animal previously. When the risk of an animal group having at least one reactor disclosed in the group was investigated using the location of the animal groups within the farm by monthly periods, the risk increased with the number of cattle in the groups when these were housed and with the presence of badgers in the fields when they were grazing. This thesis has provided a deep investigation into the risk factors that can affect the introduction and persistence of infection with M. bovis in cattle herds, and the importance that cattle play in these factors has been highlighted.

Bovine tuberculosis (TB) is a contagious neglected zoonosis of cattle that is prevalent but under-investigated in Cameroon, hence this study was designed to assess the epidemiology of bovine TB in cattle, risks for M. bovis infection in cattle and humans; and public health implications of zoonotic bovine TB in the highlands of Cameroon. A retrospective study of meat inspection records (1994 – 2010) was done to estimate the prevalence of TB lesions in slaughtered cattle in the North West region. The prevalence of bovine TB and anti-bovine TB antibodies in live cattle based on tuberculin skin tests (2 surveys) and immune-chromatographic assays respectively were carried out in the Western and Adamawa highlands of Cameroon. The performance of the tuberculin tests for bovine TB diagnosis in cattle using various tuberculin skin test cut-off points against the detection of anti-bovine TB antibodies (hypothesised risks of exposure) was compared. Suspected TB lesions from slaughtered cattle and infected human sputa were cultured on Lowentein – Jesen and Middlebrook 7H9 media to isolate mycobacteria agents for molecular genotyping using genomic deletion analysis and spoligotyping. Risk factors for exposure and transmission of zoonotic bovine TB infection of cattle and cattle professionals, and its public health significance were determined using structured questionnaires. Seventeen years of meat inspection record revealed that suspect TB lesions were identified in 599 of 129,165 slaughtered cattle at the Bamenda abattoir. The lungs and associated lymph nodes (over 60%) were the most affected tissues. Other results showed that the prevalence of anti-bovine TB antibodies in cattle in the study regions was 37.17%. Chi square statistics revealed that irrespective of the tuberculin test cut-off value (P<0.05; χ2>48), strong associations existed between the detection of anti-bovine TB antibodies and disease status. A 95% confidence interval analysis of the comparative cervical tuberculin tests revealed that the prevalence rates were 4.67% – 7.15%, 12.02% – 15.67% and 20.56% – 24.98% at the ≥ 4mm, ≥ 3mm and ≥ 2mm cut-off points, respectively. Overall, the best test performance was realised at ≥ 3-mm, though the ≥ 2-mm cut-off point predicted more positive reactors. Age, sex, breed and husbandry practices served as significant (P<0.05) risks to the prevalence and exposure of bovine TB in cattle. The feedbacks from cattle professionals suggested that there was high possibility of cattle to cattle and cattle to human transmission of bovine TB such as intimate and repeated animal / animal and animal / human interactions, consuming unpasteurised milk and eating raw meat. Genomic deletion analysis of cultured isolates showed evidence of M. tuberculosis from cattle and M. bovis from human while spoligotyping identified five cattle M. bovis strains; and four spoligotype patterns that had not been previously described anywhere. The study has important epidemiological and public health implications requiring prompt and decisive actions from the Cameroonian authority towards controlling zoonotic bovine TB in both humans and animals. A multidisciplinary approach is needed for further collaborative research and effective control strategies such as enhancing the awareness of people to this deadly disease through continuous education, proper food handling and personal hygiene, healthy husbandry practices and maintenance of the environment.

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The zoonotic tuberculosis whose etiologic agent is the Mycobacteirum bovis belonging to the Mycobacterium tuberculosis complex (M. tuberculosis, M. bovis, M. africanum, M. microti, M. canettii and M. caprae) causes diseases in humans, cattle and other animals in several countries of the world. In humans, M. bovis can determine the same clinical onsets forms that M. tuberculosis. Before the programs for the control and eradication of bovine tuberculosis and the event of the milk pasteurization, the main forms of zoonotic tuberculosis were the extrapulmonary with emphasis for renal tuberculosis in adults, lymph node tuberculosis in children due to the mechanism of M. bovis penetration throughout gastrointestinal tract, where its main sources were unboiled or unpasteurized milk and derivates. Once that M. bovis is related with tuberculosis cases in humans, there is a concern with assure the quality and safety of milk and dairy products, aiming to prevent or minimize risks to human health. Considering that Brazil is a great producer of milk, the bovine tuberculosis is endemic in Brazilian herds, the importance of assure the quality and safety of milk and derivates, this study aimed to i) carry out a systematic review about the situation of zoonotic tuberculosis in the world, ii) estimate the prevalence of milk and cheese informal consumption and associated factors to these comsumtion kinds in a population of high social vulnerability in Juiz de Fora, Brazil, as well as iii) to evaluate the occurrence of M. bovis in raw cheeses produced in the region of Parnaiba, Piaui, Brazil. In the systematic review was found that it is still recommended educational efforts directed at high-risk populations to infections caused by M. bovis as workers who deal with livestock and agro-food industry, particularly in areas and countries with an extensive agribusiness in which bovine population is still contaminated by M. bovis. In addition, the dissemination of the agent from animals to humans in developing countries remains as a real danger, mainly through the consumption of raw milk and derivates. Prevalences of raw milk and derivates consumption were of 11.4% and 43.9%, respectively. The variables, age, history of residence in a rural environment, type of dwelling, occupation, place of residence and history of excessive alcohol consumption x in the last year, were associated (p ≤ 0.05) with the consumption of raw milk and the variables place of residence, occupation and history of excessive alcohol consumption were associated (p ≤ 0.05) with the consumption of cheese made with raw milk. In the study to assess the occurrence of M. bovis in raw cheese was found a rate of 10% of positive samples evidenced by qRT-PCR, alerting for the possibility of M. bovis transmission throughout milk and cheeses consumed raw. The present study showed that the zoonotic role of M. bovis remains possible in Brazil. There were significant rates of raw milk and darivates consumption and M. bovis evidences in raw cheeses were verified. These findings should alert the health and agriculture authorities for the need of preventive mesures.
A tuberculose zoonótica cujo agente etiológico é o Mycobacteirum bovis pertencente ao Complexo Mycobacterium tuberculosis (M tuberculosis, M bovis, M africanum, Mmicroti,M canettii e M. caprae) causa doenças em seres humanos, bovinos e outros animais em vários países do mundo. Nos humanos, M. bovis pode determinar as mesmas formas clínicas dos acometimentos que M. tuberculosis. Antes dos programas de controle e erradicação da tuberculose bovina e do evento de pasteurização do leite, a principal forma infecciosa era a extrapulmonar com destaque para tuberculose renal nos adultos, tuberculose ganglionar em crianças, devido à via de infecção principal ser o trato gastrointestinal, sendo as principais fontes o leite e lácteos não fervidos ou não pasteurizados. Uma vez que M. bovis está relacionado com inúmeros casos de tuberculose em humanos, existe uma preocupação com a qualidade e a inocuidade do leite e produtos lácteos, visando prevenir ou minimizar riscos à saúde humana. Considerando-se que o Brasil é um grande país produtor de leite, a presença de M. bovis em rebanhos brasileiros, a importância da qualidade do leite e o potencial zoonótico associados, este estudo objetivou i) realizar uma revisão sistemática sobre a situação da tuberculose zoonótica no mundo, ii) estimar a prevalência, o consumo de leite e queijo não pasteurizados e fatores associados em uma população de alta vulnerabilidade social de Juiz de Fora, Brasil, bem como iii) avaliar a ocorrência de M. bovis em queijo coalho na região de Parnaiba, Piauí Brasil. No estudo de revisão sistemática verificou-se que ainda são necessários esforços educativos direcionados a populações de alto risco para infecções por M. bovis, como trabalhadores que lidam com pecuária ou agroindústria de alimentos. Estes se localizam em áreas com uma agroindústria extensiva, onde a população bovina ainda está contaminada por M. bovis. Além disso, a disseminação do agente entre animais e seres humanos em países em desenvolvimento permanece como um perigo real, principalmente por meio do consumo de leite e derivados crus. No estudo, verificou-se que a taxa de consumo atual de leite cru e queijo feito com leite cru foi de 11,4% e 43,9%, respectivamente. As variáveis, idade, histórico de residência no meio rural, tipo de moradia, ocupação, local de moradia e histórico de consumo viii exagerado de álcool no último ano, apresentaram-se associados (p ≤ 0,05) ao consumo de leite cru e as variáveis local de residência, ocupação e histórico do consumo exagerado de álcool apresentaram-se associados (p ≤ 0,05) ao consumo de queijo feito com leite cru. No estudo sobre ocorrência de M. bovis em queijos coalho, verificou-se uma taxa de 10% de amostras evidenciadas positivas pela técnica qRT-PCR, o que reforça a possibilidade de transmissão desse patógeno via lácteos confeccionados com leite cru. O presente estudo demonstra que a transmissão zoonótica de M. bovis no Brasil permanece viável, dadas as altas taxas de consumo de lácteos informais e a presença de M. bovis em produtos artesanais verificadas, o que deve servir de alerta às autoridades de saúde e agricultura sobre a necessidade de medidas preventivas.

This study was conducted to confirm the presence of bovine tuberculosis (BTB) and determine its prevalence, based on skin test reactivity, in cattle reared under extensive farming conditions in the Govuro district, Inhambane province, Mozambique. The study was comprised of a primary screening test using the single intradermal test (SIT) in randomly selected animals from Colonato and Sede dip tanks in Govuro. Positive reactors to the SIT were tested again with bovine and avian tuberculin using the single intradermal comparative test (SICTT) 7 weeks after the SIT. The sample size was calculated using Win Episcope 2.0 based on 95% confidence to detect a 2% expected prevalence using the SIT, with a 1% accepted error and accounting for a total population size of 7208. The calculated sample size was 682 animals. To compensate for the probability of 20% default in reading, the sample size was increased to 853. During the testing process (SIT), it was evident from the first 3 reading days that the apparent prevalence (61, 94%) was higher than expected (2%), hence we decided to stop when the total number of cattle was 530. During the testing process (SIT), it was evident from the first 3 reading days that the apparent prevalence (61.94%) was far higher than expected (2%), hence we decided to stop when the total number of cattle was 530. This was due to the fact that, at such a high prevalence, it would not be necessary to achieve as high a precision as 1% accepted error. A sample size of 530 would be sufficient to achieve a precision of 4% accepted error, which was regarded as more than adequate. The 530 cattle, 3 or more years of age, were selected using systematic random sampling from the two dip tanks (Colonato 371 and Sede 159 animals). All animals were identified by numbers painted, dorsally on the sacral region. Out of 530 tested cattle by SIT, 268 were read, and 166/268 (61.94% with 95% confidence interval [CI]: 55.8 – 67.8%) were found positive, with visible swallow at the injection site. Apparent prevalence (AP) was found to be 61.94% while the true prevalence (TP) was 75.92%. The predictive value of a positive result (PV+) was found to be 87.9%. No significant difference in apparent prevalence between the two areas was detected by Fisher’s exact test (P = 0.11). By SICTT, out of 28 animals positive reactors to SIT, 21 were possible to read, and 13/21 (61.9%; 95% CI: 55.1 – 89.3%) were found positive. A three year old bull, positive reactor to the SIT, was slaughtered, and a detailed post mortem was carried out and organs with visible lesions were collected for further laboratory testing (histopathology, culture and isolation of M. Bovis and PCR). Later on, 30 more positive reactors to the SIT test were slaughtered: 25/30 (83.3%) showed visible lesions compatible with BTB, and total condemnation of carcass was made in 3/25 (12%) due to generalized lesions. The high prevalence rate of skin test positive animals as well as gross lesions and histopathology were confirmed to be BTB by the isolation and identification of M. Bovis by culture and PCR. Our results suggest that bovine tuberculosis is highly prevalent in Govuro district and may thus represent a potential health problem of zoonotic tuberculosis in humans. Our results suggest that BTB has reached the plateau phase of endemicity in cattle in Govuro district. In this context, the positive predictive value of the SIT is very high and thus the use of the SICTT as a confirmatory test has a limited value and should not be advocated. Our results further indicate that no other prevalence study of BTB should be conducted in the next few years in Govuro district, unless comprehensive control measures are implemented. The focus of further studies should be on the isolation and the molecular characterization of M. Bovis from cattle and humans in order to assess transmission routes and the role played by BTB in human TB cases in Govuro district. Copyright
Dissertation (MSc (Veterinary Tropical Diseases))--University of Pretoria, 2009.
Veterinary Tropical Diseases
unrestricted

A comparative study was conducted on the immunology, pathology, and epidemiology of bovine tuberculosis (TB) between 2004 and 2008 in Bos indicus (Arsi zebu) and Bos taurus (Holstein) in Ethiopia. A total of 153 cattle were used for immunological and pathological studies while 5,924 (500 from intensive farm and 5,424 from pasture) cattle were used for epidemiological studies. Comparative intradermal tuberculin (CIDT) test, gamma interferon (IFN-γ) test, lateral flow assay, multiple antigen print assay, enzyme-linked immuno-spot assay, interleukin-4 (IL-4) and IL-10 assays were used. IFN- γ responses to mycobacterial antigens were higher (for all: P<0.05) in Holstein than in Arsi zebu. But both breeds exhibited similar T cell and antibody specificities to mycobacterial antigens. Holstein kept indoors produced higher IFN-γ responses (for all: P<0.001) to mycobacterial antigens than those kept on pasture. Pathology of bovine TB was more severe (P<0.05) in Holsteins than in Arsi zebus as well as in Holsteins kept indoors (P<0.001) than in those kept on pasture. Pathology was localised in the digestive tract in cattle kept on pasture while it was localised in the respiratory tract in cattle kept indoors. At a cut-off >2mm, the sensitivity of CIDT was 69% (95% CI=58.5%, 79%) while it was 59% (95%CI = 49%, 69%) at a cut-off >4mm. Its specificity at both cut-off points was 97% (95%CI=89%, 100%). At cut-off >4mm, the apparent prevalence was 13.5% while it was 16.0% at cut-off >2mm, and was higher in Holstein than in Arsi zebus both at a cut-off >4mm (P<0.001) and cut-off >2mm (P<0.001). The true prevalence at a cut-off >4mm was 18.5% while it was 19.6% at a cut-off >2mm. In grazing cattle, of the total 40 isolates, 12 were specified as M. tuberculosis, 7 were M. avium subspecies while only a single isolate was M. bovis while in intensive husbandry, all the isolates (41) were confirmed to be a single strain of M. bovis (SB1176). All the strains of M. tuberculosis isolated from cattle had similar patterns with M. tuberculosis strains isolated from farmers in the area. In conclusion, Holsteins exhibited higher T cell responses to mycobacterial antigens, and higher prevalence and more severe pathology of bovine TB as compared to Arsi zebus. Besides, the results of this study suggest the transmission of M. tuberculosis between farmers and their cattle.

The significant social and economic losses as a result of bovine tuberculosis (bTB) present a continuous challenge to cattle industries in the United Kingdom (UK) and worldwide. Furthermore, as a zoonotic disease, bTB may pose a threat to humans. The potential transmission of bTB in cattle, estimated by the basic reproductive ratio (R0) was found to range between 1.0 and 1.9 in previous studies. In the UK, there has been an overall increase in bTB incidence in the last two decades despite national control and eradication programmes spanning over five decades. Such programmes mainly consist of surveillance based on the administration of skin tests and culling of animals reacting positive to these tests. Animal mobility restrictions are implemented in this case. At the same time, several studies have demonstrated that there is significant host genetic variation in individual cattle susceptibility to bTB, making the disease amenable to improvement with genetic or genomic selection. In addition, genomic analyses enhance the understanding of genetic mechanisms underlying the disease and its dynamics. The overall aim of this PhD thesis was to address existing scientific research gaps on the genetics of bTB resistance in dairy cattle. The following specific objectives were set: 1) to identify genomic regions underlying susceptibility to bTB using novel trait definitions, 2) to quantify the impact of long-term genetic selection for increased resistance to bTB on disease prevalence and dynamics and 3) to determine the consequences of genetically selecting for increased resistance to bTB on other economically important traits in dairy cattle. Genome-wide association studies (GWAS), regional heritability mapping (RHM) and chromosomal association analyses were applied in order to identify genomic regions associated with bTB (objective 1). Phenotypes comprised de-regressed estimated breeding values of 804 Holstein-Friesian sires obtain from the UK national genetic evaluation for bTB. Phenotypes pertained to three bTB trait definitions: i) positive reactors to the skin test with positive post-mortem examination results (phenotype 1); ii) positive reactors to the skin test regardless of post-mortem examination results (phenotype 2) and iii) as in (ii) plus non-reactors and inconclusive reactors to the skin test with positive post-mortem examination results (phenotype 3). In all cases, non-reactors without a subsequent positive post-mortem were considered to be healthy animals with regards to bTB. Genotypes based on a 50K SNP DNA array were available and a total of 34,874 SNPs remained after quality control. The estimated polygenic heritability for susceptibility to bTB was 0.26, 0.37 and 0.34 for phenotypes 1, 2 and 3, respectively. GWAS identified a putative SNP on Bos taurus autosomes (BTA) 2 associated with phenotype 1, and another on BTA 23 associated with phenotype 2. Genomic regions encompassing these SNPs were found to harbour potentially relevant annotated genes. RHM confirmed the effect of these genomic regions and identified new regions on BTA 18 for phenotype 1 and BTA 3 for phenotypes 2 and 3. Heritabilities of the genomic regions ranged between 0.05 and 0.08 across the three phenotypes. Chromosome association analysis indicated a major role of BTA 23 on susceptibility to bTB. A stochastic genetic epidemiological model based on four main disease states, namely susceptible (S), exposed (E), infectious (I) and test-sensitive (T), was developed to address objective 2. Effects of selection for increased resistance to bTB were investigated in a closed, genetically heterogeneous simulated population whose structure reflected the UK national dairy herd. Disease dynamics reflected real bTB data from the UK national genetic evaluation. The proposed genetic epidemiological model was implemented to simulate breakdowns under both absence and presence of selection. Genetic selection was simulated over 20 generations in 50 replicates, while exploring various selection intensities reflecting selection of the 10, 25, 50, 70 and 100% (no selection scenario) most resistant sires. Results indicated that selection significantly reduced the average underlying susceptibility across generations. The risk of breakdown was reduced by half after 4 and 6 generations for high selection intensities (10 or 25% of sires selected) and after 9 and 15 generations for low selection intensities (50 or 70% of sires selected). The average percentage of secondary cases was reduced to less than 1% in 4 and 5 generations for high selection intensities, and in 7 and 11 generations for low selection intensities. The reduction in the number of secondary cases across generations could also be indicative of the possible impact of genetic selection on the basic reproductive ratio (R0) which is defined as the number of secondary cases that results from an infectious individual in a naive population. Genetic selection also reduced severity and duration of breakdowns across generations. Finally, with regards to objective 3, a stochastic simulation was used to investigate the long-term effects of selection for resistance to bTB on other economically important traits in the UK dairy selection programme. Selection was simulated in a genetically heterogeneous population across 10 generations in 50 replicates. Animal genetic values for bTB and other traits were simulated based on variance and genetic correlation estimates obtained from literature. Independent culling levels selection of sires was applied in every generation whereby selection was first based on increasing resistance to bTB, then improving either an overall index, milk fat yield (FY) or milk protein yield (PY). This mimics real life practices regarding the newly released national genetic evaluations for bTB resistance. The overall index comprised several traits of interest such as milk yield (MY), FY, PY, feet and legs (FL), mammary (MAM), milk somatic cell count (SCC), calving interval (CI), non-return to service at 56 days (NR56) and lifespan (LS). A fertility index (FI) consisting of CI and NR56 was also considered in the analyses. Regarding bTB, different levels of selection intensities were explored corresponding to selection of the 10, 25, 50, 70 and 100% (no selection) most resistant sires. Two levels of selection intensity on the overall index, FY or PY were considered corresponding to selecting the best 5 and 10% of sires that were left after first selecting for bTB resistance. Results indicated that selection for increased bTB resistance would generally not have far-reaching consequences on other important traits. As expected, susceptibility to bTB declined with time and increasing selection intensity. Trends for all production traits (MY, FY and PY) in the present study were affected by selection for increased bTB resistance because of their significant genetic correlations with bTB. However, body conformation traits (FL and MAM) were not affected by selection for increased bTB resistance due to zero correlation assumed between these traits and bTB in the present study. Selection on bTB hampered improvement of SCC but enhanced LS because it was correlated unfavourably with SCC but favourably with LS. In all selection scenarios, the overall index improved and was generally not affected by selection for bTB resistance. Similarly, the FI was not affected by selection on bTB in all cases. However, secondary selection on production traits only (FY or PY) led to a decline in FI. Results presented in this thesis add insight into the genetic architecture of bTB and offer a prediction of potential effects of genetic selection for increased resistance to bTB in dairy cattle. The genomic regions and candidate genes identified to be associated with susceptibility to bTB will assist to further elucidate pathways critical to cattle susceptibility to bTB.
Consistent with previous studies of other populations and trait definitions, results from genomic association analyses suggest that susceptibility of cattle to bTB is heritable and likely a polygenic trait, amenable to improvement by genetic and/or genomic selection. Embarking on routine selection for resistance to bTB will reduce future bTB prevalence and severity of breakdowns across selection generations, as manifested by results of this thesis. The results also highlight the importance of considering selection as a complementary strategy to existing interventions. This has the potential to accelerate control and ultimate eradication of bTB. This strategy could assist the UK to achieve the national goal of being officially bTB free by 2038. Furthermore, as indicated by results of this thesis, selection against bTB in the national breeding programme will not adversely affect other economically important traits. Assimilation of bTB into the overall index will better manage possible antagonistic correlations between bTB susceptibility and some of the other traits.

Com o intuito de determinar a prevalência da brucelose e da tuberculose bovinas em rebanhos e em fêmeas em idade reprodutiva, além de estudar os fatores de risco relacionados a ambas as doenças, na região de Andradina, Araçatuba, Dracena, Presidente Prudente, Presidente Venceslau e Tupã, foi realizado um estudo transversal, que envolveu 93 municípios do Estado de São Paulo. Foram amostrados 247 rebanhos, dos quais coletou-se sangue de 2.177 bovídeos para o exame de brucelose e realizou-se a tuberculinização comparada em 3.678 animais. Em relação à brucelose, foram diagnosticados 30 focos, com uma prevalência de propriedades igual a 11,2% [7,9 - 15,6] e de animais 2,7% [1,5 - 4,8]. Segundo a análise de regressão logística, o fator de risco para a brucelose, considerado significante nesta região, são os rebanhos 25% maiores, ou seja, aqueles que têm mais de 23 fêmeas em idade reprodutiva, justificado por uma Razão de Odds de 4,61 [2,06 - 10,34]. A tuberculose apresentou um menor número de focos, iguais a 17, cuja prevalência de propriedades foi de 6,3% [4,0 - 10,0] e a de animais equalizou 0,3% [0,2 - 0,6]. O fator de risco para a tuberculose é a utilização de pasto comum com outras propriedades, cuja Razão de Odds equivale a 3,04 [1,1 - 8,45]. A principal conclusão é que o trânsito de bovídeos entre propriedades deve ser compulsoriamente acompanhado de documento sanitário, ou seja, da Guia de Trânsito Animal, e que esta deve ser emitida somente com a exigência de exames para as duas doenças, independente da finalidade da movimentação dos animais.
In an effort to determine the prevalence of bovine tuberculosis and brucellosis in herds and females in reproductive age, in addition to studying the risk factors related to both diseases in the regions of Andradina, Araçatuba, Dracena, Presidente Prudente, Presidente Venceslau e Tupã, a cross-sectional study was performed involving 93 municipalities in the State of São Paulo. 247 herds were sampled, from which blood was collected from 2,177 bovids for the brucellosis exam and tuberculinization was performed comparing 3,678 animals. As for brucellosis, 30 outbreaks were diagnosed, with a prevalence of 11.2% [7.9 - 15.6] for properties and 2.7% [1.5 - 4.8] for animals. According to the logistic regression analysis, the risk factor for brucellosis, considered significant in this region, are herds which are 25% bigger, therefore those with more than 23 females in reproductive age, justified by an Odds Ratio of 4.61 [2.06 - 10.34]. Tuberculosis revealed fewer outbreaks, equal to 17, where prevalence for properties was 6.3% [4.0 - 10.0] and for animals was equal to 0.3% [0.2 - 0.6]. The risk factor for tuberculosis is shared pasture usage with other properties, with an Odds Ratio equal to 3.04 [1.1 - 8.45]. The main conclusion is that bovid transit between properties must be compulsorily accompanied by a sanitary document, in other words the Animal Transit Guide, and that such document must be issued solely with tests requirements for both diseases, regardless of the purpose of animal transiting.

Thesis (PhD)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Bovine tuberculosis (BTB), caused by bacteria of the Mycobacterium tuberculosis complex is reported to cause economic and public health negative impact in countries where it is prevalent. The control of the disease has been a difficult task worldwide. The main object of this thesis was to use molecular tools to generate useful information to contribute to the design of appropriate BTB control measures in Mozambique. To do so we considered a deep knowledge of the BTB history in Mozambique to be essential. The search was largely based on the reports produced annually by the Veterinary Services and other available information. We found reports of BTB in Mozambique as early as 1940. These cases were mainly identified as a result of post-mortem meat inspection. The higher numbers of cases reported were from 8 locations, namely Maputo, Magude, Vilanculos, Beira, Chimoio, Tete, Quelimane and Nampula, and served as a basis to decide the locations to perform prevalence and molecular epidemiologic studies. Prevalence studies were done in 10 districts selected based on the history of a high number of BTB case reports (intentionally biased towards locations presumably with higher prevalence), a high cattle density, but also to represent districts from the south, centre and north of Mozambique. A representative sample was defined, based on all livestock areas or villages in Massingir and Govuro Districts or by randomly selecting small-scale and commercial herds in 8 districts, specifically Manhiça, Chibuto, Buzi, Gondola, Mutarara, Mogovolas, Angoche and Mecanhelas. Results were obtained from 6983 cattle tested using tuberculin testing. Apparent prevalence varied from 0.98% in Massingir to 39.6% in the Govuro, with prevalence as high as 71.4% in some livestock areas/herds. The analysis of risk factors showed no noteworthy difference with respect to the sex of the animal. Younger age had significantly lower odds of infection compared to the older age class. There was a tendency of cattle from small-scale herds to have lower prevalence when compared to the commercial herds. From the prevalence studies, 187 tissue and 41 milk samples from BTB reactors were collected. Additionally 220 tissue samples were obtained from the Central Veterinary Laboratory routine diagnostic work. Samples were subject to bacteriological culture and a collection of 170 M. bovis isolates were obtained. Eight additional isolates were supplied from another study. All isolates were subjected to molecular typing using spoligotyping, and a sub-sample using MIRU-VNTR and regions of difference (RD) analysis. Fifteen different spoligotype patterns were identified of which 8 were not previously registered in the Mbovis.org database. The pattern SB0961 accounted for 61% of the isolates and was found in all areas of the country investigated. We hypothesize that this was one of the first clones to be introduced in Mozambique. Twenty-nine isolates had the pattern SB0140, which is specific for the European 1 (Eu1) clonal complex. Eleven isolates with this spoligotype were subjected to RD analysis, and all isolates had the Eu1 specific deletion. These were all isolated from cattle from the south of Mozambique and the majority from commercial farms that imported cattle, mainly from South Africa, where the Eu1 clonal complex is common. There were no isolates of the African 1 (Af1) or African 2 (Af2) clonal complexes that are frequent in Central-West Africa and East Africa, respectively. The clones identified from different farms and districts, strongly suggest routes of transmission and/or common source of infection. In conclusion, our results show a potential increase in the prevalence of BTB in Mozambique even taking into consideration i) that the selection of locations in our study was biased towards locations with a history of higher BTB prevalence and ii) the use of a more sensitive technique i.e. the testing in the middle neck region as opposed to the testing in the caudal fold as used in previous studies. Even if no cattle to human transmission was found in studies done in Mozambique so far, the evidence of M. bovis shedding through milk and the lack of correct practices to prevent animal to human transmission (consumption of raw milk), strongly suggests that there is zoonotic risk; a subject that needs to be investigated. The results presented in this work also strengthen the need to reinforce the current regulations that require a negative BTB test result before cattle importation. The same should be enforced for the internal movements, as the frequency of shared genotypes (Spoligotype and MIRU) from cattle originating from different parts of the country strongly suggest intra-contry transmission of BTB.
AFRIKAANSE OPSOMMING: Beestering (BTB), wat veroorsaak word deur bakterieë van die Mycobacterium tuberculosis kompleks, het ‘n negatiewe impak op die ekonomiese en publike gesondheid in lande waar dit voorkom. Die beheer van die siekte is ‘n moeilike taak wêreldwyd. Die hoofdoel van hierdie tesis was om molekulêre toetse te gebruik om nuttige inligting te genereer wat sal bydra tot die ontwikkeling van toepaslike BTB beheermaatrëels in Mosambiek. Om dit te kon doen, was dit noodsaaklik om ‘n indiepte kennies te hê van BTB geskiedenis in Mosambiek. Die soektog was gebaseer op jaarlikse verslae van Veearts Dienste en ander beskikbare inligting. Ons het verslae gevind van BTB in Mosambiek so vroeg as 1940. Hierdie gevalle is hoofsaaklik geïdentifiseer as gevolg van roetine na-doodse inspeksie van vleis. Hoër getalle van sulke gevalle is geïdentifiseer in 8 distrikte, naamlik Maputo, Magude, Vilanculos, Beira, Chimoio, Tete, Quelimane en Nampula; en het gedien as ‘n basis vir die seleksie van studieareas vir die voorkoms studies. Voorkoms studies is uitgevoer in 10 distrikte gekies op grond van die geskiedenis van 'n hoër aantal BTB gevalle in hierdie areas (doelbewus bevooroordeeld teenoor plekke vermoedelik met 'n hoër voorkoms), asook‘n hoë digtheid beeste, maar ook om distrikte in die suide, middel en noorde van Mosambiek te verteenwoordig. ‘n Verteenwoordigende steekproef is geïdentifiseer gebaseer op al die vee-gebiede of dorpe in Massingir and Govuro distrikte óf deur kleinskaalse en kommersiële kuddes lukraak te kies in 8 distrikte, spesifiek Manhica, Chibuto, Busi, Gondola, Mutarara, Mogovolas, Angoche en Mecanhelas. Resultate is verkry deur 6983 beeste te toets met behulp van die tuberkulien vel toets. Skynbare voorkoms het gewissel van 0,98 % in Massingir tot 39,6 % in Govuro, met voorkoms so hoog as 71,4 % in sommige vee gebiede/ kuddes. Die ontleding van risiko faktore het geen noemenswaardige verskil met betrekking tot die geslag van die dier gewys nie. Jonger ouderdom diere het ‘n aansienlike laer kans van infeksie gehad in vergelyking met die ouer ouderdom klas. Daar was 'n neiging van beeste van kleinskaalse kuddes om ‘n laer voorkoms te hê in vergelyking met die kommersiële kuddes. Van die voorkoms studies, is 187 weefsel- en 41 melkmonsters van BTB reaktors ingesamel. ‘n Addisionele 220 weefselmonsters is verkry vanaf die Sentrale Veterinêre Laboratorium se roetine diagnostiese werk. Monsters was onderhewig aan bakteriologiese kweking en 'n versameling van 170 M. bovis isolate is verkry. Agt bykomende isolate is voorsien deur 'n ander studie. Alle isolate was onderhewig aan molekulêre-tipering met behulp van spoligotipering en ‘n subgroep met behulp van MIRU-VNTR en analise van genomies diverse areas. Vyftien verskillende spoligotipering patrone is geïdentifiseer, waarvan 8 nie voorheen in die Mbovis.org databasis geregistreer is nie. Die SB0961 patroon is geïdentifiseer vir 61% van die isolate en gevind in alle dele van die land wat ondersoek was. Ons hipotese is dat hierdie een van die eerste klone was wat voorgestel is in Mosambiek. Nege en twintig isolate het die SB0140 patroon gehad wat spesifiek is aan die Europese 1 (EU1) klonale kompleks. Elf isolate met hierdie spoligotipering patroon is verder geanaliseer om genomies diverse areas te identifiseer, waarvan almal die Eu1 spesifieke delesie getoon het. Hierdie isolate is almal geïsoleer uit beeste van die suide van Mosambiek, asook beeste gevind op kommersiele plase wat hoofsaaklik vanuit Suid Afrika invoer- waar die EU1 klonale kompleks algemeen is. Daar is geen isolate van die Afrikaans 1 (AF1) of Afrikaans 2 (AF2) klonale komplekse nie, dikwels gevind in onderskeidelik Sentraal-Wes-Afrika en Oos- Afrika. Isolate wat in verskillende plase en distrikte geïdentifiser is dui roetes van transmissie en/ of a gemeenskaplike bron van infeksie aan. Ten slotte, ons resultate dui op 'n moontlike toename in die voorkoms van BTB in Mosambiek, selfs met inagneming dat i) die keuse van areas in ons studie is bevooroordeeld teenoor areas met 'n geskiedenis van hoër BTB voorkoms en ii) die gebruik van 'n meer sensitiewe tegniek d.w.s. toetsing in die middel nekgebied i.p.v. toetsing in die stert vou soos gebruik in vorige studies. Selfs al is geen bees-na-mens-oordrag gevind nie, is die bewys van M. bovis oordrag deur melk en die gebrek aan korrekte prosedures om dier-na-mens-oordrag te voorkom (verbruik van nie-gepasturiseerde melk), ‘n sterk bewys van die soönotiese risiko; ‘n onderwerp wat ondersoek moet word. Die resultate van hierdie ondersoek beklemtoon die behoefte om die huidige regulasies wat ‘n negatiewe BTB toetsuitslag vereis voor beeste ingevoer word, te versterk. Dieselfde maatreëls moet ingestel word vir interne beweging van beeste, omdat die frekwensie van gedeelde genotipes (Spoligotipering en MIRU) tussen beeste met oorsprong uit verskillende dele van die land aandui dat interne oordrag van BTB plaasvind.

The persistent increase of bovine tuberculosis (bTB) over the past twenty years has put a substantial strain on both the British economy and the welfare of livestock. However, the development of an effective bTB vaccine has been continually hindered by the lack of knowledge on the immune response following Mycobacterium bovis (M. bovis) infection. In collaboration with the TB Research Group at the Veterinary Laboratories Agency (VLA, Surrey), this thesis is part of a much wider strategy managed by the Department of Environment, Food and Rural Agency (DEFRA) aimed at elucidating the immunopathogenesis of M. bovis and to develop more effective infection control measures. The specific focus of this thesis was to enable a stronger understanding of the bovine immune response over different periods of M. bovis infection and to apply this new knowledge in evaluating the efficacy of a novel BCG vaccination. Time Course Study: Knowledge of time dependent cytokine expression following M. bovis infection would aid vaccine development by revealing potential correlates of protection. Interferon gamma (IFN-γ), tumour necrosis factor alpha (TNF-α), interleukin (IL) 4 and 10 expression were analysed using quantitative (q) PCR in formalin fixed bovine lymph nodes following five, twelve and nineteen weeks of M. bovis infection. A strong pro-inflammatory/ T helper 1 (TH1) lymphocyte response was evident at five weeks post M. bovis infection, represented by IFN-γ and TNF-α expression (log2 copies of 6.5 and 2.15, respectively) in the absence of IL4. Between five and twelve weeks of infection, a significant increase was observed in IL10 (log2 copies from 5.97 to 8.27, p<0.01, Mann Whitney test), accompanied by an increase in both IFN-γ (log2 7.53) and TNF-α (log2 3.94). This data conformed to a recently described aspect of TH1 lymphocytes, a ‘self-limiting’ nature in which cells produced both IFN-γ and IL10 with the aim of controlling the heightened pro-inflammatory response. The role of IL10 as an immunosuppressive became evident when comparing cytokine expression between four different types of thoracic lymph node; the left bronchial (LB), cranial mediastinal (CRM), caudal mediastinal (CM) and cranial tracheobronchial (CRT) nodes. The LB and CRM lymph nodes produced significantly higher levels of IFN-γ expression (log2 copies between 8.2 and 10) as compared to the CM and CRT (log2 copies between 2.6 and 5.5, p<0.001, Mann Whitney test). Further analysis of the data as a profile of cytokine expression for each lymph node type revealed that IFN-γ was dominantly expressed within the LB and CRM nodes, whereas within the CM and CRT nodes, IL10 was the dominant cytokine. The former nodes also displayed a higher level of pathological damage (represented by mean percentage area coverage of granuloma, 33.6 and 20%, respectively) as compared to the CM (13%) and the CRT lymph node types (10.8 %). This suggests conflicting roles for IFN-γ and IL10 in the development of immune-associated pathology. Following nineteen weeks of infection, the expression levels of IFN-γ, TNF-α and IL10 reduced (log2 6.22, 3.02 and 7.03, respectively) implying a loss of the cellular response. The later stages of bovine tuberculosis have been shown within the literature to display characteristics of a humoral rather than cell mediated response. However, within this study at nineteen weeks post infection IL4 (an important cytokine in the development of the humoral response) remained undetectable. The results from this study therefore confirm the importance of the cell mediated immune profile in response to M. bovis infection as well as the integral role of IFN-γ in both protection and pathology. It also further demonstrates the involvement of IL10 in controlling the IFN-γ response and highlights this cytokine as being potentially important in future immunologybased vaccination studies. BCG Vaccination Study: The current vaccine used against human tuberculosis, BCG, has provided variable results on protection against infection in experimental bovine studies. The BCG bacterium has lost a comparatively large quantity of genomic DNA through attenuation since its primary production in 1921, of which the majority represented genes encoding antigenic proteins. MPB70 and MPB83 are differentially expressed between BCG sub-strains due to a single nucleotide polymorphism in the alternative sigma factor K (SigK). BCG Pasteur has been shown to produce low levels of these antigenic proteins; however complementation of BCG Pasteur with a copy of sigK from BCG Russia resulted in up-regulating expression. It was therefore hypothesised that the recombinant BCG (sigK) Pasteur would prove more efficient in controlling M. bovis infection by inducing a stronger protective immune response post vaccination. IFN-γ, TNF-α, IL 4 and 10 expression were analysed using qPCR within the freshly dissected lymph nodes of five experimental cattle groups; BCG Pasteur vaccinated M. bovis challenged, BCG (sigK) Pasteur vaccinated challenged, non-vaccinated infected, non-vaccinated noninfected and BCG Pasteur vaccinated non-infected. Five weeks following infection, a strong IFN-γ mRNA response was detected in both the non-vaccinated and vaccinated cattle (mean log2 copies between 9.6 and 10.5 as compared to between 7.84 and 8.58 in the non-infected cattle). M. bovis infection also induced a significant reduction in IL10 mRNA levels in both vaccinated and non-vaccinated cattle (mean log2 14.4 in the infected groups compared to 15.5 in the non-infected cattle, p<0.005, Mann Whitney test) although there was little difference in TNF-α expression (mean log2 copies between 11.06 and 11.8 in all five groups). Interestingly, IL4 mRNA was detectable only within the two non-infected control groups (mean log2 12.4), further supporting the concept of a strong cell mediated response after five weeks of infection. Vaccination prior to challenge had an effect on IFN-γ mRNA levels only, as both the BCG Pasteur and BCG (sigK) Pasteur vaccinated groups displayed a smaller increase in IFN-γ mRNA following challenge (mean log2 10.3 and 9.6, respectively) as compared to the nonvaccinated group (mean log2 10.5). This reflected the role of vaccination in priming the immune response to enable more rapid elimination of the bacteria and subsequently inducing a lesser pro-inflammatory response. Interestingly, the BCG Pasteur vaccinated group appeared to control the immune response to a greater extent, as IFN-γ mRNA was significantly similar to that observed in the non-vaccinated non-infected group (mean log2 8.58, p>0.05, Mann Whitney test). In addition to the qPCR data, levels of IFN-γ and TNF-α protein (represented by the number of cells producing these proteins) were also analysed by immunohistochemistry. IFN-γ protein in the five experimental groups displayed the same pattern as that observed for IFN-γ mRNA expression (p<0.001, Spearmans correlation coefficient). However, analysis of TNF-α protein revealed significant differences between the five groups (p<0.005, Kruskal Wallis test) in contrast to that observed for the mRNA levels (p>0.05, Spearmans correlation coefficient) suggesting that posttranscriptional controls may play an important role in TNF-α translation. The difference in IFN-γ mRNA and protein expression between the two vaccination groups was also reflected within the pathological data. Although both BCGs reduced levels to below that of the non-vaccinated group (represented by mean percentage area coverage of granuloma, 59%), the BCG Pasteur group displayed less pathology (mean 6%) compared to the BCG (sigK) Pasteur cattle (mean 35%). It was suggested that the increased antigenic repertoire of the recombinant BCG (sigK) Pasteur did result in a stronger stimulation of the immune response post vaccination but that, as a consequence the bacterial threat was eliminated more rapidly.

A cross-sectional study was conducted from February 2011 to August 2012 to investigate the status and identify risk factors for Bovine Tuberculosis (BTB) and cattle Brucellosis. A total of 1277 cattle from 6 selected dairy farms were tested. The farms were purposively selected on suspected risk. Samples were analysed using Rose Bengal Test (RBPT) and Complement Fixation Test (CFT) for Brucellosis and Comparative Intradermal Tuberculin Test (CITT) for BTB. The results revealed the overall prevalence of 1.6% for Brucellosis and no BTB was found. Logistic regression analysis revealed that age of cattle, herd size and number of calves a cow has had significant association with Brucellosis with p-values 0.0071, 0.0490 and 0.000 respectively. The role of location (p>0.05), gender (p>0.05) and breed (p>0.05) in the occurrence of the disease was not statistically significant at α=0.05, although higher rates were obtained in females and Jersey breed. Questionnaires were also administered to 47 individuals a total of 12 females and 35 males. Most respondents were not aware about cattle brucellosis and cattle tuberculosis. Consumption of raw or unpasteurized milk still occurs with 74.75% of respondents revealed.

Bovine tuberculosis (bTB) is a chronic disease of cattle caused by Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex group of bacteria. bTB infection in cattle is not uniformly distributed throughout Great Britain but concentrated in the southwest of England and Wales. Vaccination of cattle might offer a long-term solution for controlling the disease and priority has been given to the development of a cattle vaccine against bTB. Identification of biomarkers in tuberculosis research remains elusive and the goal of this project is to identify host correlates of protection and biomarkers of progressive bTB in cattle. Previous work in cattle has revealed three distinct stages following vaccination and challenge with bTB: immune responses following vaccination; early protective anamnestic responses after M. bovis infection in protected cattle; and late responses indicative of progressive disease in unprotected animals. These three stages can be replicated in our mouse model of M. bovis infection. Therefore, we hypothesized that by studying global gene expression during these stages we will identify, respectively, predictors of protection, correlates of protective immunity, and biomarkers of pathology. Because both cattle and mice present these three stages, mice were used for genome-wide expression profiling of systemic responses after BCG vaccination and M. bovis infection to identify candidate biomarkers of protective immunity. RNA was prepared from spleen cells of vaccinated and control mice prior and post-M. bovis challenge. Global gene expression was determined using murine microarrays, and candidate genes identified were validated in cattle by RT-QPCR. After BCG vaccination, we defined a specific pulmonary gene expression signature related to the connective tissue development and function network that predicted vaccine success before M. bovis challenge. In addition, a Th17-related cytokine profile was found that correlated with vaccine-induced protective immunity following infection with virulent M. bovis in the lung as well as additional genes that were up-regulated in the spleens of vaccinated animals post-infection related to neutrophil biology and inflammation. In antigen-stimulated splenocytes we found statistically significant modulation of 1109 genes early after infection and 1134 at later time-point post-infection. 618 of these genes were modulated at both time points. In the lung 282 genes were significantly modulated in animals post-infection. Amongst the most strongly up-regulated genes were GzmA in spleen, and Cxcl9 and IL-22 in lungs. The expression of the most up-regulated genes identified in the murine studies were evaluated using PBMC from BCG vaccinated and unvaccinated calves prior and post experimental infection; and uninfected and naturally infected cattle. Thus, we confirmed that the expression of IFN-γ IL-17, IL-22, Cxcl10 and Ido1 predicted vaccine success and correlated with protection. Cxcl9, GzmA and IL-22 following in vitro stimulation with PPD was significantly increased in infected cows compared to naïve animals. Thus, we have demonstrated that murine transcriptome analysis can be used to predict the responses in cattle. This study has therefore prioritized both biomarkers predicting vaccination success before challenge, biosignatures that are potentially associated with protective immune responses after challenge and biomarkers of pathology that will be useful to evaluate future vaccine candidates. Key words: Bovine tuberculosis, host responses, vaccination, diagnosis, host transcriptome, microarrays

Dissertação de Mestrado Integrado em Medicina Veterinária
Nesta dissertação pretendeu-se identificar potenciais indicadores de infeção por M. bovis em bovinos que apresentaram lesões suspeitas de Tuberculose bovina (69), em Portugal em 2014. Para isso avaliaram-se as informações resultantes da inspeção post mortem, informações referentes aos animais (idade, sexo, raça e aptidão) e ao número de movimentos realizadas entre explorações. Outro objetivo foi avaliar o critério da decisão sanitária aplicado aos animais com lesões suspeitas de Tuberculose. Verificou-se uma associação entre a consistência da lesão e o resultado do exame laboratorial histopatológico e bacteriológico, em que a maioria dos animais com lesão caseo-cálcaria foi positivo ao exame laboratorial. As lesões dos animais positivos localizaram-se quase exclusivamente nos linfonodos retrofaríngeos, brônquicos, mediastínicos e pulmão, tendo-se verificado uma associação entre o local da lesão e o resultado laboratorial obtido. A decisão sanitária quando duas ou mais regiões estavam afetadas foi de uma forma geral a reprovação total, enquanto quando apenas uma região se encontrava afetada, houve reprovação parcial. Nos resultados referentes às informações dos bovinos, verificou-se que a maioria tinha mais de 6 meses e tinha como aptidão a produção de carne. Em relação ao histórico dos movimentos entre explorações, observou-se que o grupo de animais positivos ao exame laboratorial realizou em média mais movimentos entre explorações que o grupo dos animais negativos e que a maioria dos animais nasceu no Alentejo.
ABSTRACT - This dissertation was intended to identify potential indicators of infection by M. bovis in animals that showed suspicious lesions of bovine tuberculosis (69), in Portugal in 2014. For that we evaluated the information resulting from the post mortem inspection, information related to animals (age, sex, breed and aptitude) and to the history of animals. Another objective was to verify the decision concerning the meat of animals infected by bovine tuberculosis. It was found that most the animals with suspicious lesions, that showed a lesion with a caseo-calcarius consistency, were positive to laboratory examination. The lesions of positive animal were located almost exclusively in the lymph nodes retropharyngeal, bronchial, mediastinal and lungs. The decision of the veterinary was generally the total condemnation when two or more anatomic regions were affected and trimming when one region was affected. It was found that most of the animals had more than 6 months old and were cattle raised for meat production. The results concerning the history of the animals showed that, the positives group made more movements between farms (mean) than the negatives, and that the majority was born in Alentejo.

Bien que la France soit reconnue indemne de tuberculose bovine (TB) par l’Union Européenne depuis 2001, une centaine de nouveaux foyers sont déclarés chaque année. Deux des principaux mécanismes de propagation de l’infection entre troupeaux bovins sont l’introduction d’animaux infectés et les contacts au pâturage. L’objectif de cette thèse a été de quantifier les rôles respectifs des échanges commerciaux de bovins et des contacts au pâturage « par-dessus la clôture » dans la circulation de la TB en France entre 2005 et 2014. Pour cela, nous avons combiné des méthodes d’analyse de réseaux sociaux et de modélisation dynamique. Nos analyses ont montré que les contacts par le commerce étaient une origine probable pour 12% [5 - 18] des infections déclarées en France entre 2005 et 2014, contre 73% [68 - 78] pour la transmission locale. Cependant, nous avons pu observer que les contacts par le commerce permettaient à l’infection de coloniser de nouvelles zones. Puis nous nous sommes intéressés au risque structurel du réseau du pâturage. À partir d’une exploitation donnée, il était possible d’atteindre quasiment toutes les autres exploitations du territoire métropolitain. Il semble donc facile pour l’agent de la TB de se propager par les contacts de voisinage au pâturage. Enfin, afin de reconstituer la propagation de la TB en France entre 2005 et 2014, nous avons développé un modèle dynamique stochastique individu-centré, dirigé par les données et avec un pas de temps mensuel. Ce modèle reproduit une dynamique intra- et inter-élevages de l’infection, avec une transmission de l’infection entre élevages par le commerce et au pâturage. Il a permis de confirmer la facilité de propagation de l’infection via les contacts au pâturage. En conclusion, les mécanismes de propagation de la TB sont complémentaires : le commerce permet une diffusion sur de longues distances et le pâturage facilite la propagation locale. Le dispositif de lutte contre la tuberculose bovine doit donc s’appuyer combiner les mesures de contrôle afin de cibler plusieurs mécanismes de propagation
Although France was declared free of bovine Tuberculosis (bTB) by the European Union in 2001, a hundred of outbreaks are reported every year. Cattle movements and contacts on pastures are considered the main between-herd transmission routes of bTB. The aim of this work was to quantify the respective roles of live cattle trade and “over the fence” contacts on pastures in the spread of bTB in France between 2005 and 2014, using social network analysis and dynamic modelling. Results showed that cattle movements may be the origin of 12% [5 - 18] of the French outbreaks between 2005 and 2014, versus 73% [68 - 78] due to the transmission on pasture. However, cattle movements appeared to allow the introduction of the bacteria into new areas. In a second step, the structural risk resulting from the French pasture network was studied. Almost all of the premises owning pastures were mutually connected by pastures neighbourhood relationships, on the territory. Thus, the spatial configuration of pastures appeared favourable to the spread of bTB in France. Finally, to mimic the spread of the infection in France between 2005 and 2014, a stochastic individual-based model was developed. It was driven by the data with a monthly time step. This model reproduced the within- and between-herd dynamic, with a between-herd transmission due to cattle movements and contacts on pastures. The easy spread of the bacteria through the network of French pastures was confirmed using the model. In conclusion, cattle movements and contacts on pastures are complementary paths for bTB spread: cattle movements allow the long-range spread, whereas contacts on pasture make easier the short-range spread. Hence, control programs must target several routes of transmission to be able to eradicate bTB

Tuberculosis (TB) is an ancient infectious disease that has been infecting different populations around the globe and it has also been considered as one of the most successful human and animal disease. TB found in animals such as cattle and other known bovids is known as bovine tuberculosis. Bovine tuberculosis (BTB) is an infectious disease found in cattle mainly caused by Mycobacterium bovis. M. bovis is a member of the Mycobacterium tuberculosis complex (MTC) together with M. tuberculosis, M. africanum, and M. canetti where the natural host is humans; whereas M. caprae, M. microti and M. pinnipedii usually have animals as their natural host. In this study the molecular characterization of the MTC from cow milk in the Eastern Cape was investigated. One hundred and twenty samples (40 ml each) were collected from three dairy farms in the Eastern Cape, South Africa. These samples were processed using a modified Petroff decontamination method. Sample processing was followed by DNA isolation using a Zymo Bacterial/Fungal DNA Kit and the amplification and detection of the MTC was done using the Seeplex MTB Nested ACE assay. The drug susceptibility tests were done using GenoTypeMTBDRplus assay which detects mutations and resistance to INH (isoniazid) and RMP (rifampicin). The milk isolates were further analyzed using a spoligotyping method which is based on the PCR amplification of a highly polymorphic direct repeat locus in the M. tuberculosis genome which detects and types the MTC. A percentage of 20.8 % samples were found to be positive for MTC using the Seeplex MTB Nested ACE assay. There were 42.1 % samples that were resistant to both INH and RMP with the rest sensitive to either INH or RMP. The spoligotyping method showed that 78.3 % samples resembled Family 33 strains and the rest (21.7 %) resembled a spoligotyping signature known to be that of M.africanum. Both these strains belong to the Ancestral lineage with Indo-Oceanic and West Africa 2 lineage. The outcomes of our study showed that molecular methods for detection of MTC can be applied directly on milk samples without the need for culturing.

Orientador: Antonio Carlos Paes
Coorientador: Jane Megid
Banca: Hélio Langoni
Banca: Rogério Giuffrida
Resumo: A brucelose e tuberculose são enfermidades infectocontagiosas de evolução crônica, de caráter zoonótico, que representam grandes prejuízos econômicos à bovinocultura leiteira e saúde pública. Os objetivos deste trabalho foram: estudar a situação epidemiológica destas enfermidades nas propriedades fornecedoras de leite para o Programa Municipal de Botucatu intitulado "Laticínio Escola"; determinar o grau de conhecimento dos pequenos produtores acerca destas doenças por meio de um questionário elaborado para essa finalidade. Ao final do questionário os produtores receberam instruções técnicas sobre os temas abordados e foi realizado um trabalho social de conscientização sobre a importância zoonótica e sanitária. O estudo foi conduzido em 22 pequenas propriedades leiteiras do município de Botucatu-SP, que fornecem leite para creches e escolas municipais. Os testes realizados foram os preconizados pelo Programa Nacional de Controle e Erradicação de Brucelose e Tuberculose (PNCEBT), que são sorológicos para brucelose e imunoalérgico para tuberculose. Os animais reagentes a ambos os testes foram retirados da propriedade, levados ao Hospital Veterinário da FMVZ/UNESP, campus de Botucatu, para realização de exame necroscópico. O total de animais testados para Tuberculose foi 736, e para Brucelose 512. Encontrou-se pelo menos um bovino positivo para tuberculose em 13,6% (3/22) das propriedades, e para brucelose em 31,8% (7/22). A prevalência das enfermidades observada foi de 0,8% (6/736) e 2,3% (12/512) para tuberculose e brucelose, respectivamente. Os dados deste estudo foram semelhantes aos encontrados em trabalhos regionais da literatura nacional. Portanto, na microrregião de Botucatu-SP, estas enfermidades ainda representam grande relevância socioeconômica, sanitária e de saúde pública
Abstract: Brucellosis and tuberculosis are chronic infectious diseases and considered as zoonosis, which represent large economic losses to dairy cattle and public health. Our objectives were to study the epidemiological situation of these diseases in the properties that supply milk to the Municipal Program of Botucatu entitled "Dairy School"; determine the degree of knowledge of small farmers about these diseases through a questionnaire prepared for this purpose. At the end of the questionnaire the producers received technical instruction on the topics and we performed a social work awareness of zoonotic importance and health. The study was conducted in 22 small dairy farms of Botucatu-SP, which provide milk for kindergartens and public schools. The tests performed were those recommended by the National Program for Control and Eradication of Brucellosis and Tuberculosis (PNCEBT), which are serologic for brucellosis and tuberculosis imunoalergic. Reagents animals to both tests were removed from the property, taken to the Veterinary Hospital of FMVZ/UNESP, Botucatu, to perform necropsies. The total number of animals tested for tuberculosis was 736, and for brucellosis 512. It has been found Brucellosis at least one positive for tuberculosis in 13.6% (3/22) of properties, for brucellosis in 31.8% (7/22). The prevalence of disease observed was 0.8% (6/736) and 2.3% (12/512) for tuberculosis and brucellosis, respectively. Data from this study were similar to those in regional work of the national literature. Therefore, in the micro region of Botucatu, these diseases still represent very important socio-economic, health and public health
Mestre

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A brucelose e tuberculose são enfermidades infectocontagiosas de evolução crônica, de caráter zoonótico, que representam grandes prejuízos econômicos à bovinocultura leiteira e saúde pública. Os objetivos deste trabalho foram: estudar a situação epidemiológica destas enfermidades nas propriedades fornecedoras de leite para o Programa Municipal de Botucatu intitulado Laticínio Escola; determinar o grau de conhecimento dos pequenos produtores acerca destas doenças por meio de um questionário elaborado para essa finalidade. Ao final do questionário os produtores receberam instruções técnicas sobre os temas abordados e foi realizado um trabalho social de conscientização sobre a importância zoonótica e sanitária. O estudo foi conduzido em 22 pequenas propriedades leiteiras do município de Botucatu-SP, que fornecem leite para creches e escolas municipais. Os testes realizados foram os preconizados pelo Programa Nacional de Controle e Erradicação de Brucelose e Tuberculose (PNCEBT), que são sorológicos para brucelose e imunoalérgico para tuberculose. Os animais reagentes a ambos os testes foram retirados da propriedade, levados ao Hospital Veterinário da FMVZ/UNESP, campus de Botucatu, para realização de exame necroscópico. O total de animais testados para Tuberculose foi 736, e para Brucelose 512. Encontrou-se pelo menos um bovino positivo para tuberculose em 13,6% (3/22) das propriedades, e para brucelose em 31,8% (7/22). A prevalência das enfermidades observada foi de 0,8% (6/736) e 2,3% (12/512) para tuberculose e brucelose, respectivamente. Os dados deste estudo foram semelhantes aos encontrados em trabalhos regionais da literatura nacional. Portanto, na microrregião de Botucatu-SP, estas enfermidades ainda representam grande relevância socioeconômica, sanitária e de saúde pública
Brucellosis and tuberculosis are chronic infectious diseases and considered as zoonosis, which represent large economic losses to dairy cattle and public health. Our objectives were to study the epidemiological situation of these diseases in the properties that supply milk to the Municipal Program of Botucatu entitled Dairy School; determine the degree of knowledge of small farmers about these diseases through a questionnaire prepared for this purpose. At the end of the questionnaire the producers received technical instruction on the topics and we performed a social work awareness of zoonotic importance and health. The study was conducted in 22 small dairy farms of Botucatu-SP, which provide milk for kindergartens and public schools. The tests performed were those recommended by the National Program for Control and Eradication of Brucellosis and Tuberculosis (PNCEBT), which are serologic for brucellosis and tuberculosis imunoalergic. Reagents animals to both tests were removed from the property, taken to the Veterinary Hospital of FMVZ/UNESP, Botucatu, to perform necropsies. The total number of animals tested for tuberculosis was 736, and for brucellosis 512. It has been found Brucellosis at least one positive for tuberculosis in 13.6% (3/22) of properties, for brucellosis in 31.8% (7/22). The prevalence of disease observed was 0.8% (6/736) and 2.3% (12/512) for tuberculosis and brucellosis, respectively. Data from this study were similar to those in regional work of the national literature. Therefore, in the micro region of Botucatu, these diseases still represent very important socio-economic, health and public health

The aim of this study was to investigate the diversity and prevalence of non-tuberculous mycobacteria (NTM) in cattle, African buffaloes and their environments in South Africa and the potential of these NTM to elicit cross- reactive immune responses in these animal species which may in turn lead to false diagnosis of bovine tuberculosis. A total of 40 NTM species were identified during a countrywide survey. Mycobacterium terrae, Mycobacterium nonchromogenicum, Mycobacterium vaccae/ Mycobacterium vanbaalenii and a group of isolates closely related to Mycobacterium moriokaense (M. moriokaense-like isolates) were the four most frequently isolated species. Further characterization of M. moriokaense- like isolates revealed two novel NTM species which were named Mycobacterium malmesburii sp.nov. and Mycobacterium komanii sp.nov. respectively. Genomes of M. nonchromogenicum, M. malmesburii sp. nov., M. komanii sp. nov., and M. fortuitum ATCC 6841 were elucidated and investigated for genes encoding homologues of M. bovis predominant immunogenic proteins. These included genes encoding for the Esx family proteins (esx genes), mpb70, mpb63, mpb64, hspX, tpx, Rv1120c, canA and dnaK. The esx gene orthologs encoded in ESX-1 (esxA and esxB), ESX-3 (esxH and esxG), esxR, and ESX-4 (esxT and esxU) loci were identified in the NTM genomes while those encoded in ESX-2 locus were absent in all the four NTM genomes and only esxN (encoded in the ESX-5 locus) and its homologue, esxK were present in M. nonchromogenicum. Gene orthologs encoding for MPB70 (M. malmesburii sp.nov. and M. komanii sp.nov.), DnaK (all four NTM species), CanA (all four NTM species), MPB64 (all four NTM species), Rv1120c (in all four NTM species), TpX, MBP63 and HspX (all in M. nonchromogenicum and M. fortuitum), were found in the NTM genomes. In contrast orthologs of mpb83 and espC were not detected in any of the four NTM. We could not judge just based on the overall protein sequence homologies of the antigens whether the NTM homologues will give rise to cross-reactive immune responses. We consequently checked the existence in NTM of epitopes shown to be immunogenic in M. bovis and M. tuberculosis. Amino acid sequence alignment of the EsxA and EsxB of the NTM sequenced in this study as well as M. smegmatis, M. bovis and M. tuberculosis respectively was done to investigate their similarities at “immunogenic” epitope level. In this analysis, we found that the six bovine T-cell recognized epitopes of M. bovis ESAT-6 described by Vordermeier et al., 2003 and 2007 had similarities to those of M. fortuitum and M. nonchromogenicum (showing sequence similarity of as high as 81.28% and as low as 52.9% ). Likewise a certain degree of sequence similarity between the six M. bovis CFP 10 immunogenic epitopes and those of the NTM species (highest similarity of 75% observed between all NTM and M. bovis and lowest similarity of 50% between M. komanii sp.nov, M. malmesburii sp.nov and M. bovis.) was observed. Still, with sequence homologies of less than 100% between the M. bovis immunogenic epitopes and those of the NTM, it was difficult to unambiguously predict T-cell cross-recognition. Comparison of the EsxR and EsxH amino acid sequences at immunogenic epitope level, revealed higher sequence similarities in the epitopes of NTM and those of M. bovis than the predicted protein sequences of EsxA and EsxB. A sequence similarity of 100% was observed between two of the five M. bovis immunogenic epitopes of EsxR and those of M. fortuitum, M. malmesburii sp. nov. and M. komanii sp.nov. Full cross- recognition of these NTM EsxR epitopes is therefore highly likely, and may lead to misdiagnosis of bovine Tuberculosis (BTB). The other three EsxR/EsxH epitopes shown to be immunogenic in M. bovis also exist in the three NTM showing similarity of as low as 77.7%.
Thesis (PhD)--University of Pretoria, 2015.
WOTRO Science for Global Development
Genomics Research Institute (GRI)
Veterinary Tropical Diseases
PhD
Unrestricted

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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
The bovine tuberculosis, a worldwide anthropozoonosis caused by Mycobacterium bovis, is a disease of chronic evolution that affects mainly cattle and buffalo and is characterized by the progressive development of nodular lesions called tubercles. Considering that this disease brings economic losses to livestock and impacts public health, this study was carried out to characterize the epidemiological situation of tuberculosis in adult cows in the State of Goias, evaluating its prevalence, regional distribution, and interaction of risk factors related to the disease, to provide data for more efficient surveillance activities for the detection and sanitation of residual foci. A descriptive cross-sectional study was also conducted to characterize the productive profile of Goias’ herds and identify management practices related to impacts on public health. The State was divided in three regions, according to the main characteristic of cattle in each region, categorized as beef, milk and mixed. In each stratum 300 farms were randomly sampled , after having the producer`s agreement. A predetermined number of animals was drawn depending on the amount of females over 24 months of age therein. The randomly selected animals underwent tuberculin by comparative cervical technique. An epidemiological questionnaire was applied in each property, to check health and management practices that could be associated with the risk of infection by the disease. The descriptive analysis showed that most of Goias’ dairy herds have no defined breed, have a low productivity, attained by manual daily milking. In terms of public health, there are still worrying rates of consumption and sale of raw milk and dairy products, as well as the disposal of breeders in slaughterhouses without official sanitary inspection. 18,659 animals from 900 farms were tested. No animal reagent to the test was detected in region 1. For region 2, the herd prevalence was 8.67% [5.73-12.74%], and the animal prevalence was 0.9% [0.21-1.58%]. For region 3, the herd prevalence was 1.00% [0.21-2.89] and the animal prevalence was 0.30% [0.10-0.49%]. For the whole state, the herd prevalence was 3.43% [2.20-4.67%], and the animal prevalence 0.30% [0.10-0.49%]. The risk factors (odds ratio, OR) associated with the presence of the infection after univariate and multivariate analysis were: location of the property in region 2 (OR = 12.05 [3.52-41.28]), milking two or three times a day (OR = 6.27 [2.72 to 14.44]). The veterinary assistance was presented as a protective factor (OR = 0.38 [0.15-0.94]). In conclusion, tuberculosis has a low prevalence in adult cows in the State of Goias and it is more prevalent in the south and southeast region of the State, where dairy farms are concentrated. The low prevalence verified favors the implantation of an eradication program, with the adoption of an active surveillance system considering the risk factors.
A tuberculose bovina, antropozoonose de ocorrência mundial, causada pelo Mycobacterium bovis, é uma enfermidade de evolução crônica que acomete principalmente bovinos e bubalinos e caracteriza-se pelo desenvolvimento progressivo de lesões nodulares, denominadas tubérculos. Considerando que esta doença traz prejuízos econômicos à pecuária e tem impacto na saúde pública, realizou-se este estudo com o objetivo de caracterizar a situação epidemiológica da tuberculose em fêmeas bovinas adultas no Estado de Goiás, avaliando sua prevalência, distribuição regional e a interação dos fatores de risco relacionados com a enfermidade, visando fornecer subsídios para ações de vigilância mais eficientes na detecção e saneamento de focos residuais. Objetivou-se também, através de um estudo transversal descritivo, caracterizar o perfil produtivo da bovinocultura goiana e identificar aspectos relacionados a agravos em saúde pública. O Estado foi estratificado em três circuitos produtores, de acordo com a principal aptidão do rebanho bovino daquela região, categorizada em corte, leite e misto. Em cada estrato foram amostradas aleatoriamente 300 propriedades, nas quais, após concordância do produtor, foi sorteado um número pré-estabelecido de animais em função do quantitativo de fêmeas bovinas acima de 24 meses ali existentes. Os animais sorteados foram submetidos à tuberculinização, pela técnica cervical comparada. Foi aplicado, em cada propriedade, questionário epidemiológico para verificar as práticas sanitárias e de manejo que poderiam estar associadas ao risco de infecção pela doença. Observou-se na análise descritiva, que a maioria do rebanho leiteiro goiano não apresenta padrão racial definido, possui baixa produtividade, obtida com uma ordenha diária, de forma manual. No aspecto de saúde pública, concluiu-se que ainda são preocupantes os índices de consumo e venda de leite cru e seus derivados e o abate de reprodutores de descarte em abatedouros sem inspeção sanitária oficial. Foram testados 18.659 animais, oriundos de 900 propriedades. No estrato 1, não foi detectado nenhum animal reagente ao teste. No estrato 2, a prevalência foi de 8,67% [5,73–12,74] para propriedades e de 0,9% [0,21–1,58] para animais. No estrato 3, obteve-se 1,00% [0,21–2,89] para propriedades e 0,30% [0,10–0,49] para animais. A prevalência global foi de 3,43% [2,20–4,67] para propriedades e de 0,30% [0,10–0,49] para animais. Os fatores de risco associados à condição de foco, após realização de análise uni e multivariada, foram: localização da propriedade no estrato 2 (OR = 12,05 [3,52–41,28]), realização de duas ou três ordenhas diárias (OR = 6,27 [2,72–14,44]). A assistência veterinária se apresentou como fator de proteção (OR = 0,38 [0,15-0,94]). Concluiu-se que a tuberculose tem baixa prevalência em fêmeas bovinas adultas, em Goiás e que a enfermidade está mais presente nas regiões sul e sudeste do Estado, onde se concentram as propriedades de exploração leiteira. A baixa prevalência verificada propicia a implantação de um programa de erradicação, com adoção de um sistema de vigilância ativa considerando os fatores de risco.

碩士
國立臺灣大學
獸醫學研究所
99
The tuberculin test-and-culling program for eradication of bovine tuberculosis has been carried out in Taiwan for more than 50 years; however, sporadic tuberculin test reactors still occur, and Taiwan is still defined as an epidemic country of bovine tuberculosis by OIE. In this study, a total of 137 dairy cattle with skin test-positive reaction, originated from 12 dairy farms, were euthanatized and sampled for mycobacterial isolation, pathological examination, molecular diagnosis, and bacterial strain genotyping. Mycobacterium spp. could be isolated in 40 cattle (40/137; 29.2%), 29 of them (29/137; 21.17%) were identified as Mycobacterium bovis, another 11 cattle (11/137; 8.03%) were other Mycobacterium spp. other than M. bovis. Tuberculous lesions were identified in 89 cattle (89/137; 64.96%) following gross and/or microscopic examination. The most frequently affected site was mediastinal lymph node, followed by retropharyngeal lymph node, hilar lymph node, mesenteric lymph node, and lung. Sixty nine cattle (69/137; 50.37%) were identified as M. bovis infection through mycobacterium isolation and PCR assay, 59 of them (59/137; 43.07%) developed tuberculous lesion. Five genotypes of M. bovis were found among 34 skin test-positive cattle from four different farms by a molecular genotyping method based on variable number tandem repeat (VNTR) analysis, and the phylogenetic relationships between genotype I, IV and genotype III, V were also noted. The findings uncovered the actual incident status of bovine tuberculosis in the cattle under routine tuberculin test survey, indicating that M. bovis still is the major cause of bovine tuberculosis and is also an important allergen for the positive reaction of tuberculin test in Taiwan. However, there are Mycobacterium spp. other than M. bovis and M. tuberculosis that may trigger the tuberculin test reaction of dairy cattle in Taiwan. Based on the data obtained from the 12 dairy farms, there are more than one VNTR strains of M. bovis present in Taiwan, and the same VNTR strain may infect cattle from different counties. The present study further supports that VNTR genotyping can be used to differentiate different strains of M. bovis and can be a powerful tool for epidemiological investigation of bovine tuberculosis in Taiwan.

碩士
國立臺灣大學
獸醫學研究所
99
Intradermal tuberculin test (ITT) is the official test for diagnosis of bovine tuberculosis in Taiwan. ITT is a cell-mediated immune response that acquires two times of restraint and handling the animal to complete the examination, and safety issue is always concerned in non-domestic animal like deer or wildlife to perform this test. In addition, repeated or confirmed ITT test in the previous ITT positive animal should be performed in three months later which results in a significant drawback in the aspect of disease control and eradication. Using blood samples to perform enzyme-linked immunosorbent assays (ELISAs) or polymerase chain reaction (PCR) may provide an alternative assay to correct the shortcomings of ITT. In this study, blood samples collected from cattle and deer were tested by PCR and ELISA, and the results were subsequently correlated with the results of pathology, microbiology and PCR in the tissue examined. Using culture results as the golden standard in 147 ITT positive cattle, the sensitivity of PCR in peripheral blood mononuclear cells (PBMC) was 7.7% (2/26) and the specificity was 95.0% (115/121), the sensitivity of the ELISA was 0% (0/26) and the specificity was 95.0% (115/121). Under the same conditions of 17 deer, the sensitivity of PCR in PBMC was 0% (0/7) and the specificity was 100% (10/10), the sensitivity of the ELISA was 85.7% (6/7) and the specificity was 50% (5/10). In deer, the correlation coefficient between ELISA and ITT was 0.647(substantial agreement), and the correlation coefficient between ELISA and culture was also 0.647 (substantial agreement). Therefore, the blood tests for Mycobacterium bovis infection in cattle maybe not so helpful; however, blood tests are effective to detect Mycobacterium bovis infection in deer.

Bovine Tuberculosis is a chronic debilitating disease of cattle and other animals with a worldwide distribution and transmitted mainly through the inhalation of aerosols. The aim of this study was to determine the prevalence of BTB in the cattle population of selected dip tanks in Swaziland. Furthermore, the zoonotic risk to farmers whose cattle are infected with BTB was assessed by means of a questionnaire survey. Abattoir surveillance identified 16 dip tanks of study where at least 10 % of the cattle were tested for BTB using the comparative intra-dermal skin. In five of these dip tanks, the same cattle were tested for BTB using the IFN-γ Test. Eight BTB skin test positive animals were slaughtered and a detailed post mortem examination was conducted and samples collected for the isolation of M. bovis. Concurrent with BTB testing, a questionnaire survey was conducted to determine risk factors for humans. The prevalence of BTB was found to be 6.75 % in the study population and 20 % of BTB positive animals were diagnosed by both the CIST and IFN-γ, indicating a correlation for the test positive animals in the two tests. M. bovis was isolated from seven of the eight animals slaughtered. Farmers’ knowledge of BTB as a cattle disease and serious zoonosis is insufficient and inadequate while consumption practices of products of bovine origin exposes them to the risk of infection by M. bovis. There is a need to investigate the extent of M. bovis infections in the human population.
Dissertation (MSc)--University of Pretoria, 2013.
gm2014
Veterinary Tropical Diseases
unrestricted

Dissertação de Mestrado em Ciências da Saúde
In Mozambique, bovine tuberculosis (BTB) is a serious problem for livestock development; however, surveillance and control programs are not applied consistently and systematically. This disease has direct economic repercussions on livestock due to lower productivity of infected animals, as well as the increased rejection of carcasses at the slaughterhouses. Due to the direct economic repercussions and indirect consequences for human health, knowing the precise distribution of the disease throughout the country is essential to define an effective control strategy and reduce BTB incidence and spread. Although the prevalence in free-ranging wildlife species is unknown, non-systematic surveys have reported a wide variation of BTB prevalence in cattle in different regions of the country and even in distinct herds of the same region. In the Govuro district the BTB’s prevalence levels previously obtained are hardly intercomparable, ranging from 1.49% in one region, using single intradermal tuberculin test (SITT) in caudal fold, to 61.94%) in another region where the SITT was applied in the middle neck region. This latter prevalence level represents one of the highest for BTB in the country and represents a serious risk for the transmission of the disease to humans. However, it should be considered that, a positive result using SITT may be related with cross-reactivity with environmental mycobacteria. We conducted a cross-sectional study in the Govuro district in order to determine the prevalence of BTB in cattle and identify associated risk factors. To access the disease burden in the district, a representative sample of the cattle population from all livestock areas (n=14) was defined using the Epicalc 2000 statistical software (Brixton Books v.1 2); assuming an expected prevalence of 10% with a standard error precision of 0.05 (5%). To compensate for noncompliance (animals selected for tuberculin test but failing the reading day), 20% more animals were targeted at testing. A total of 1136 cattle from 289 different owners were submitted to the more accurate test, the single comparative intradermal tuberculin test (SCITT). Their body condition scores, sex, age and breed were recorded to obtain a better understanding of BTB risk factors. Data analysis was performed using a logistic regression model with binary outcome and livestock area as random effect. The overall prevalence was estimated at 39.6% [95% with confidence interval (CI): 36.8-42.5] and, with the exception of the Luido area (animals from two private farmers), BTB reactors were found in all studied areas with quite diverse prevalence rates. SCITT results showed that 137 (12%; 95% CI: 10.3-14.1) out of 1136 cattle tested reacted positive to avian PPD. From 289 cattle raisers with tested cattle, 192 (66.4%; 95% CI: 60.8- 71.6) had positive cattle. Age was found to be the main individual risk factor; animals older than 4 years were more likely to be positive reactors (45.4% vs 21.9%; OR 2.9, 95% CI: 42.1 – 49.0). Females (37.2%; OR 1.1, 95% CI: 33.9 – 40.7) and animals in good body condition (35.5%; OR 35, 95% CI: 32.0 – 39.1) were associated with lower prevalence’s, although no significant differences were found. Most of the cattle included in the present study are Zebu crossbred and Landim local breed. Zebu crossbred showed a significantly higher prevalence of BTB than the Landim local breed (49.6% vs 35.6%; OR 0.7, 95% CI: 45.4 – 53.9). Thirteen out of 67 positive blood samples were BOVIGAMTM positive. This study showed a high prevalence of BTB in the Govuro district. The findings reveal an urgent need for intervention with an implementation of effective, area-based, control measures in order to reduce prevalence and incidence of the disease and prevent its spread to the human population. Data also points that further studies on the isolation and molecular characterization of the predominant strains lineages that cause tuberculosis (TB) in cattle and humans should be conducted in order to assess the potential transmission of BTB from cattle to humans.
Em Moçambique, a tuberculose bovina (BTB) representa um sério problema para o desenvolvimento da pecuária, no entanto, os programas de vigilância e controle não são aplicados de forma consistente e sistemática. Esta doença tem repercussões económicas diretas na pecuária devido à baixa produtividade dos animais infetados, bem como o aumento da rejeição de carcaças ao nível dos matadouros. Devido às repercussões económicas diretas e consequências indiretas para a saúde humana, é de particular relevância conhecer a distribuição precisa da doença em todo o país de modo a definir uma estratégia de controlo eficaz e consequentemente reduzir as taxas de incidência e propagação da doença. Pesquisas não sistemáticas têm demonstrado uma grande variação da prevalência da doença em bovinos em diferentes regiões do país e até mesmo em rebanhos distintos de uma mesma região, porém a prevalência da doença nas espécies selvagens permanece desconhecida. Estudos anteriormente desenvolvidos em momentos diferentes no distrito de Govuro obtiveram taxas de prevalências dificilmente comparáveis; utilizando a tuberculinização simples na prega caudal (1.49%) e na tábua do pescoço (61.94%). Esta última representa uma das mais altas taxas de prevalência de BTB encontrada no país. No entanto, é de grande relevância considerar que, um resultado positivo obtido a partir do SITT pode estar relacionado com reatividade cruzada com micobactérias ambientais. Com o objetivo de determinar a prevalência da BTB em bovinos e identificar os fatores de risco associados à ocorrência da doença, desenvolveu-se um estudo transversal, no distrito de Govuro. Uma amostra representativa da população bovina pertencente a todas as áreas de produção do distrito (n=14) foi definida a partir do programa estatístico Epicalc 2000 (Brixton Books v.1 2), utilizando uma prevalência estimada de 10% e uma precisão de desvio padrão de 0.05 (5%). De modo a reduzir o efeito das incomparências (animais tuberculinizados que não comparecem no dia da leitura), foram testados 20% a mais do tamanho da amostra pré determinada. Um total de 1136 animais, pertencentes a 289 proprietários foi submetido a um teste de diagnóstico mais preciso, o teste tuberculínico comparativo (SCITT). Dados relativos a condição corporal, sexo, idade e raça foram registrados para obter uma melhor compreensão dos fatores de risco associados à doença. Os dados foram analisados utilizando um modelo de regressão logística com desfecho binário e a área de pecuária como efeito aleatório. A prevalência global estimada foi de 39.6% [95% com intervalo de confiança (CI): 36.8 – 42.5]. Com exceção da área de pecuária Luido (animais pertences a dois criadores privados) todas as restantes áreas estudadas apresentaram reatores positivos. Os resultados do SCITT mostraram que 137 (12%; 95% CI: 10.3 – 14.1) dos 1136 animais testados, reagiram positivamente ao PPD aviário. Dos 289 criadores incluídos no estudo, 192 (66.4%; 95% CI: 60.8 – 71.6) possuem animais positivos. A idade foi o principal fator de risco individual. Animais com mais de quatro anos mostraram-se mais propensos a ser reatores positivos (45.4% vs 21.9%; OR 2.9, 95% CI: 42,1 – 49,0). Animais do sexo feminino (37.2%; OR 1.1, 95% CI: 33.9 – 40.7) e com boa condição corporal (35.5%; OR 35, 95% CI: 32.0 – 39.1) foram associados a prevalências mais baixas, embora não tenham sido encontradas diferenças significativas. A maioria do gado incluído no presente estudo pertence à raça Zebu mestiços e raça local Landim. A raça mestiça Zebu apresentou uma prevalência de BTB significativamente maior em relação a raça Landim (49.6% vs 35.6%; OR 0,7, 95% CI: 45.4 – 53.9). Treze das 67 amostras de sangue positivas reagiram positivamente ao BOVIGAMTM. O presente estudo demonstrou uma alta prevalência de BTB no distrito de Govuro. Esses resultados revelam uma necessidade urgente de intervenção com implementação de medidas de controlo eficazes, baseados na área, de modo a reduzir a prevalência e incidência da doença e consequentemente evitar a sua propagação para o homem. Sugere-se que novos estudos sobre o isolamento e caracterização molecular das estirpes predominantes em bovinos e humanos sejam desenvolvidos de modo a avaliar a transmissão de BTB do gado bovino para o homem.
The laboratory work presented in this thesis was done in the Laboratory of Serology of Veterinary Faculty, Eduardo Mondlane University, Maputo, Mozambique and at the Life and Health Sciences Research Institute, School of Health Sciences, University of Minho, Braga, Portugal. The financial support to perform this study was conceded by the Integrated Control of Neglected Zoonosis (ICONZ) – Africa Project and Fundação para a Ciência e a Tecnologia (FCT).

The aim of this study was to investigate the prevalence and epidemiological significance of tuberculosis (TB) in bovine and humans living at a wildlife/livestock/human interface, as well as the risk factors associated with TB transmission at that interface. The Mnisi community was chosen as it is located at the western border of the Kruger National park (KNP) and enables research at the wildlife/livestock/human interface. The first objective of the study entailed investigating the presence of bovine tuberculosis (BTB) in 10% of Mnisi?s livestock, using the comparative intradermal skin test. A low individual prevalence of 0.33 % (95% CI.0.14 ? -0.79) was detected. Further investigations into the causative agent in livestock, using genotyping techniques identified the KNP parental strain, M. bovis KNP VNTR -1 strain.1 Supporting records from the provisional Mpumalanga Veterinary Services and the physical location of dip-tanks where BTB was detected, it was established the infection was a result of spillback infection from wildlife in the neighbouring KNP. The epidemiological significance of BTB in human TB was investigated through the isolation and genetic characterisation of the Mycobacterium tuberculosis complex (MTBC) strain population in the Mnisi community. Mycobacterium bovis was not detected in the human population. However, a high genetic diversity of M. tuberculosis was observed among the 13 isolates obtained.The M. tuberculosis isolates were identified as the following eight families: T; Beijing; LAM 11_ZWE; EAI5; MANU1; X1; X2; and S families. The predominant lineage was as T family, sub-lineage ST53. Based on the high diversity (8 clusters/13isolates) and the predominance of the T family, it was concluded that the TB population structure within the Mnisi community was largely impacted by human migration from urban towns and neighbouring Mozambique. A questionnaire was administered to investigate BTB transmission risk factors at the livestock/human interface. It was established that there were low risk levels of BTB transmission at the human/livestock interface mainly based on the fact that the majority of the households in the community obtained pasteurised milk commercially, and although undercooked/raw meat and organs were preferred, the majority of respondents reported that they discarded the meat if changes in meat quality were observed.
Thesis (PhD)--University of Pretoria, 2016.
tm2016
Veterinary Tropical Diseases
PhD

This thesis presents the results of a series of studies on the epidemiology of TB in brushtail possum and domestic cattle populations in New Zealand. The first set of studies provides an analysis of the results of routine TB testing carried out in the Featherston area from July 1980 to June 2004. The median annual incidence rate of TB reduced from 4.7 cases per 1000 cattle-years at risk for the period 1986 to 1991 to 1.8 cases per 1000 cattle-years at risk for the period 1992 to 2003, coincident with the use of poisoning to control possums in the surrounding forest park (a major possum habitat area). We identified clusters of cattle TB cases adjacent to the forest park and found no evidence of spatio-temporal interaction of TB risk among farms. Our findings support the hypothesis that possums living in the forest park are a source of bovine TB in this area and that farm-to-farm transmission was not an important mechanism of infection spread. A mixed-effects Poisson regression model was developed to investigate the influence of farm-level covariates on the number of cattle confirmed with TB. The model showed that, despite intensification of possum control activities, proximity to forest parks remained a significant predictor of the number of confirmed TB cases per farm per year. Our analyses identified a significant, 3-fold increase in TB risk in dairy cattle relative to beef conditional on the size of local possum habitat, and confirmed the positive influence of cattle population size and the presence of previous infection status as a determinant of the number of confirmed TB cases per farm per year. The second set of studies investigates details of capture events recorded during a longitudinal, capturemark- recapture study of possums in a 22-hectare study site near Castlepoint, from April 1989 to August 1994. Social network analyses were used to identify contact patterns and to estimate the influence of contact on R0 for bovine TB. The average number of contacts per possum ranged from 20 to 26 per year. We estimated that TB would spread if an average of between 1.94 and 1.97 infective contacts occured per year per infected possum. We evaluated the effect of sex, habitat and contact behaviour of 26 postmortem confirmed TB cases in possums with those of 104 matched controls. Unit increases in the number of infected contacts increased the odds of TB infection by 2.61 (95% CI 1.29 – 5.29, P <0.01). Our results show that individual contact behaviour is a determinant of the presence of TB foci within this population and challenge the hypothesis that contact with many individuals increases the probability of infection. A model to predict spatial variation in possum abundance was developed using a Geographic Information System. Details of possum capture events were obtained from 157 10-trap lines distributed within 42 randomly located transects at Molesworth Station. Two GIS-based models were developed to predict the number of possums caught per line using Poisson regression techniques. The first model used remotely sensed environmental data; the second used a combination of remotely sensed and fine-scale data. Both models provided adequate predictive ability with Pearson correlation coefficients greater than 60%. We conclude that the prediction maps produced from this model provide a useful decision support tool for possum control managers. These results have implications for the management of TB in this area of New Zealand, providing the information that will allow effective control activities to be applied at significantly lower cost.