Bovine tuberculosis at the human-livestock-wildlife interface: is it a public health problem in Tanzania? A review

Evaluation and application of a milk antibody ELISA for assessing the prevalence and incidence of bovine tuberculosis in dairy herds in Hubei Province, China

Bovine tuberculosis (bTB) is a chronic zoonotic disease that is endemic in China. Current in-vitro tests for bTB are mainly based on blood assays. Collection of samples results in some stress to the sampled cattle and associated economic losses for the herd owner. This study was designed to investigate the relationship between milk and serum antibody tests for bTB in dairy cows using 85 cows with milk and corresponding blood samples. Totally 4,395 milk samples were used to assesse the apparent (test) prevalence and incidence of bTB using the milk antibody ELISA. The association between levels of bTB milk antibody and milk quality was also evaluated. Milk and serum antibody tests showed a good correlation with a 87.5% (95% CI: 61.7%, 98.4) positive agreement and 98.7% (95% CI: 95.4, 99.8) negative agreement. The animal level lactoprevalence ranged from 0.3% (95% CI: 0, 1.2) to 33.3% (95% CI: 26.6, 40.6) in different farms and the incidence rate ranged from 0 head/cow-month (95% CI: 0, 0.02) to 0.04 head/cow-month (95% CI: 0.02, 0.07). Twenty percent of sampled farms met the criteria for bTB control in China. The prevalence on large-scale farms was lower (p < 0.001) than on small farms. The bTB milk antibody levels had a negative correlation with milk yield and a positive correlation with somatic cell count (SCC), milk protein percentage (MPP) and percentage of total solids (TS). According to this research, milk ELISA could be used as a supplement of blood samples to assist in the surveillance for bTB and for alerting control and eradication of bTB.

Evidence, Challenges, and Knowledge Gaps Regarding Latent Tuberculosis in Animals

Mycobacterium bovis and other Mycobacterium tuberculosis complex (MTBC) pathogens that cause domestic animal and wildlife tuberculosis have received considerably less attention than M. tuberculosis, the primary cause of human tuberculosis (TB). Human TB studies have shown that different stages of infection can exist, driven by host–pathogen interactions. This results in the emergence of heterogeneous subpopulations of mycobacteria in different phenotypic states, which range from actively replicating (AR) cells to viable but slowly or non-replicating (VBNR), viable but non-culturable (VBNC), and dormant mycobacteria. The VBNR, VBNC, and dormant subpopulations are believed to underlie latent tuberculosis (LTB) in humans; however, it is unclear if a similar phenomenon could be happening in animals. This review discusses the evidence, challenges, and knowledge gaps regarding LTB in animals, and possible host–pathogen differences in the MTBC strains M. tuberculosis and M. bovis during infection. We further consider models that might be adapted from human TB research to investigate how the different phenotypic states of bacteria could influence TB stages in animals. In addition, we explore potential host biomarkers and mycobacterial changes in the DosR regulon, transcriptional sigma factors, and resuscitation-promoting factors that may influence the development of LTB.

Prevalence and Demographic Risk Factors of Mycobacterium tuberculosis Infections in Captive Asian Elephants (Elephas maximus) Based on Serological Assays

To address putative TB statuses of elephants and to identify and quantify potential demographic risk factors for TB, three ELISAs specific for different mycobacterial antigens (ESAT6, CFP10, MPB83) and the TB Stat-Pak assay were used as surrogate serological markers for TB infection in elephants. In view of the low number of animals of which the infected status could be confirmed (4 out of 708) Latent Class Analyses of TB serology test outcomes was used to predict the putative TB status of each of 708 elephants as positive (17.3%), inconclusive (48.7%), or negative (34%) when assessed on a population basis. Correlation between test performance of the individual assays was high between the ELISAs, but low with that of the TB Stat-Pak assay. Risk factors, assessed based on cut off values for each of the ELISAs determined by ROC analysis, included sex, BCS, age, working time, feed type, management system, camp size and region. Old age elephants were more likely to show a positive TB serology test outcome, than younger ones. Elephants working 7 h per day and the ones in good condition BCS (7-11) were less likely to be positive in TB serology testing. In addition, fewer animals in the large camp size (31-50 elephants) were found to be positive in ELISA tests, compared to elephants in the other camp sizes. In this study, the North region had the lowest percentages of elephants with positive TB test outcome, the West region and to a lesser extend the other regions showed clearly higher percentages of positive animals. Even though assays used in the present study have not been validated yet, results obtained showed promise as diagnostic or screening tests. For the diagnosis of animals suspected to be infected, the ELISA tests, once further optimized for the individual antigens, can be used in parallel. For screening of complete camps for presence or absence of infection, a single optimized ELISA test can be utilized.

Conventional knowledge, general attitudes and risk perceptions towards zoonotic diseases among Maasai in northern Tanzania

Understanding factors influencing conventional medical knowledge (CMK), general attitudes and risk perceptions of zoonotic diseases among rural residents who face risk of exposure to such diseases is important for human, livestock, and wildlife health. Focusing on Maasai from Makame, Kiteto District (Tanzania) who largely maintained a semi-nomadic lifestyle, we evaluated respondents’ CMK of causes, symptoms, treatments, and prevention methods of rabies, brucellosis, and anthrax. In addition, we identified socio-demographic correlates of CMK with respect to the target zoonoses. Finally, we assessed the relative frequency of practices that increase the risk of pathogen transmission, and compared the risk perception of the three diseases. We conducted structured interviews with Maasai respondents (n = 46) in six sub-villages of Makame and considered education, gender, age, and wealth (indicated by standardized number of livestock) as potential correlates of CMK. Respondents had greater CMK of rabies and anthrax, but feared anthrax the most. Receiving formal education increased rabies CMK (p ≤ 0.05). The CMK of anthrax and brucellosis was not associated with any of the tested variables (p > 0.05). Risk perceptions were correlated with knowledge scores for rabies and anthrax (p ≤ 0.05), and multiple interviewees reported engaging in practices that potentially enhance pathogen transmission. Specific socio-demographic attributes (i.e., formal education) may explain the observed variation in CMK of zoonotic diseases. This information can be used to develop and tailor health education programs for specific at-risk groups.

Molecular characterization and antimicrobial resistance profiles of Mycobacterium tuberculosis complex in environmental substrates from three dairy farms in Eastern Cape, South Africa

This study analysed 330 environmental substrates from three dairy farms for the occurrence, drug resistance and the genetic mutations of MTBC (Mycobacterium tuberculosis complex) in Eastern Cape, South Africa using PCR, while the Genotype MTBDRplus assay was used for drug susceptibility and genetic mutations analyses. About 17% (55/330) of the samples were positive for MTBC at 16.7% (water), 13.3% (soil) and 20% (hayfeed). Isoniazid resistance was detected in 47.3% (26/55) of the samples while 16.4% (9/55) were multidrug-resistant. Genetic mutations were detected on the rpoB gene (resistance to rifampicin) with frequencies ranging from 53.6% (D516V) to 21.4% (H526D), while mutations on the katG and inhA genes (resistance to isoniazid) ranged between 14.3% and 80%. Incidents of diverse genetic mutations in the environmental matrices suggest possible resistance to other anti-TB drugs not assayed in this study and emphasizes the need for continuous monitoring of drug resistance patterns for timely detection and control of new clonal groups of MTBC.

Survey of the knowledge, attitude and perceptions on bovine tuberculosis in Mnisi community, Mpumalanga, South Africa

Tuberculosis (TB) is a global health concern of zoonotic importance, and Mycobacterium bovis and Mycobacterium tuberculosis are the most common causes of TB in animals and humans, respectively. Integral to TB control strategies are the communities affected by this epidemic. Tuberculosis awareness by the community is an effective TB control strategy as education empowers people to make informed choices with regard to mitigating TB risk factors in their daily lives. We conducted a knowledge, attitude and perceptions survey in Mnisi pastoral community in South Africa using a semi-structured questionnaire to evaluate the level of bovine TB (bTB) awareness, and provided informed feedback to the community on the outcome of the study. Although participants were aware of TB, the knowledge of the zoonotic potential of bTB and about susceptible hosts was limited. The study findings showed knowledge gaps regarding common risk factors, including coughing while herding cattle, unsupervised/uninspected communal slaughter and improper disposal of infected meat. In contrast, it was noted that the majority of participants discarded meat with visible lesions and consumed pasteurised milk; thus, the risk of TB transmission via the ingestion route is low. Tuberculosis knowledge gaps were evident in the community, and public health and veterinary authorities need to improve relationships with stakeholders and implement awareness programmes that use a one health approach.

Bovine tuberculosis at the human-livestock-wildlife interface and its control through one health approach in the Ethiopian Somali Pastoralists: A review

Pastoralism is a way of life in which food supply is produced from animals by using a variety of herding practices based on constant or partial herd mobility in the low land areas of Ethiopia. It covers 12% of the total livestock population and 61% of the total area of land in the country. As a result of their mobile lifestyle, pastoralists are almost completely excluded from the available health services. This review article focuses on bovine tuberculosis in the Ethiopian Somali Pastoralist. It describes Mycobacterium bovis in humans, livestock, and wildlife, and how the disease can be controlled by using One Health approach. Bovine tuberculosis is a chronic bacterial disease caused by Mycobacterium bovis. A study done from 2006 to 2008 on the prevalence of BTB in Ethiopian wildlife showed that sera from 20 of 87 animals (23%) were positive for BTB. In Ethiopia there is no comprehensive report about the status of M. bovis in wildlife populations that often share habitat with livestock. A study done on bovine tuberculosis in Somali pastoral livestock showed low prevalence of the disease. An individual animal prevalence of 2.0%, 0.4%, and 0.2% was reported in cattle, camels, and goats, respectively. In a simultaneous human and cattle study in a pastoralist areas of south-eastern Ethiopia, out of 163 human Mycobacterium tuberculosis complex isolates three were M. bovis. Due to the moderate resistance of the etiological agent to the environmental conditions in one hand and the capacity of its survival in acid milk for not less than 15 days on the other and the habitual consumption of unpasteurized milk by humans make this disease a vital zoonosis in Somali pastoralists in Ethiopia. M. bovis is a pathogen at the human-livestock-wildlife interface. Diseases transmitted between humans, livestock, and wildlife are increasingly challenging public and veterinary health systems. Therefore, studies concerning the burden of the diseases in wildlife, livestock and human beings in Somali Pastoralists should be undertaken. A One Health approach that takes the wellbeing of the pastoralists, the health of their livestock and environment into consideration is also necessary for the control of BTB.

Risk Factors for Zoonotic Tuberculosis at the Wildlife-Livestock-Human Interface in South Africa

A cross-sectional study was conducted to investigate the risk factors associated with zoonotic tuberculosis in humans and its transmission to people living at the wildlife–livestock–human interface. A questionnaire was administered to collect information on food consumption habits, food handling practices, and knowledge of zoonotic TB. Sputum samples were also collected from 150 individuals that belonged to households of cattle farmers with or without a bTB infected herd. In addition, 30 milk samples and 99 nasal swabs were randomly collected from cattle in bTB infected herds for isolation of Mycobacterium bovis (M. bovis). The sputum samples were screened for TB using the GeneXpert test and this was followed by mycobacterial culture and speciation using molecular techniques. No M. bovis was isolated from TB positive sputum samples and only one sample was confirmed as Mycobacterium tuberculosis (M. tuberculosis). M. bovis was isolated from 6.6% (n = 2/30) milk samples and 9% (n = 9/99) of nasal swabs. Ownership of a bTB infected herd and consumption of milk were recognized as highly significant risk factors associated with a history of TB in the household using multiple correspondence analysis (MCA) and logistic regression. The findings from this study have confirmed the potential for zoonotic TB transmission via both unpasteurized milk and aerosol thus, the role of M. bovis in human TB remains a concern for vulnerable communities.

Bayesian Assessment of the Accuracy of a PCR-Based Rapid Diagnostic Test for Bovine Tuberculosis in Swine

Infection with the Mycobacterium bovis (M. bovis) causes a disease referred to as bovine tuberculosis (bTB), which affects a wide range of mammal hosts. Many countries have implemented control and eradication plans that have resulted in variable levels of efficacy and success. Although bTB is a notifiable disease in Argentina, and a control plan that targets cattle herds has been in place for decades, M. bovis is still prevalent in cattle, swine, and certain wild species. The aim of the paper here was to assess the sensitivity (Se), specificity (Sp), and positive and negative predictive values (PPV and NPV) of PCR from tissue, which is a test for rapid M. bovis detection in swine. Bacteriological culture was also performed for comparison purposes. A Bayesian approach was applied to estimate the accuracy of the diagnostic tests, PCR and bacteriological culture, in 266 swine samples with bTB-like lesions recovered during routine official inspections at slaughterhouses. A one-population model, assuming conditional dependence between test results, and incorporating prior information on the performance of the tests obtained from the literature, was used to estimate the tests Se and Sp. The accuracy of the combined (in parallel) application of both tests was also estimated. The Se of the PCR (82.9%) was higher than the Se of the bacteriological culture (79.9%), whereas the Sp of both tests was similar (88.5 and 89.0%, respectively). Furthermore, when both techniques were assessed in parallel, the Se of the diagnostic system increased substantially (Se = 96.6%) with a moderate Sp loss (Sp = 78.8%; PPV = 92.8%; NPV = 89%). Results suggest that the PCR, or the combined application of bacteriological culture and PCR, may serve as an accurate diagnostic tool to confirm bTB in swine samples. Results here will help the design and implementation of effective surveillance strategies for the disease in swine of Argentina and other settings in which the disease is prevalent.

Wild Animal Tuberculosis: Stakeholder Value Systems and Management of Disease

When human health is put at risk from the transmission of animal diseases, the options for intervention often require input from stakeholders whose differing values systems contribute to decisions on disease management. Animal tuberculosis (TB), caused principally by Mycobacterium bovis is an archetypical zoonotic pathogen in that it can be transmitted from animals to humans and vice versa. Although elimination of zoonotic transmission of TB to humans is frequently promoted as the raison d'être for TB management in livestock, in many countries the control strategies are more likely based on minimizing the impact of sustained infection on the agricultural industry. Where wild animals are implicated in the epidemiology of the disease, the options for control and eradication can require involvement of additional stakeholder groups. Conflict can arise when different monetary and/or societal values are assigned to the affected animals. This may impose practical and ethical dilemmas for decision makers where one or more species of wild animal is seen by some stakeholders to have a greater value than the affected livestock. Here we assess the role of stakeholder values in influencing TB eradication strategies in a number of countries including Ireland, the UK, the USA, Spain, France, Australia, New Zealand and South Africa. What it reveals is that the level of stakeholder involvement increases with the complexity of the epidemiology, and that similar groups of stakeholders may agree to a set of control and eradication measures in one region only to disagree with applying the same measures in another. The level of consensus depends on the considerations of the reservoir status of the infected host, the societal values assigned to each species, the type of interventions proposed, ethical issues raised by culling of sentient wild animals, and the economic cost benefit effectiveness of dealing with the problem in one or more species over a long time frame. While there is a societal benefit from controlling TB, the means to achieve this requires identification and long-term engagement with all key stakeholders in order to reach agreement on ethical frameworks that prioritize and justify control options, particularly where culling of wild animals is concerned.

SCREENING FOR BOVINE TUBERCULOSIS IN AFRICAN BUFFALO (SYNCERUS CAFFER) IN NGORONGORO CONSERVATION AREA, NORTHERN TANZANIA: IMPLICATIONS FOR PUBLIC HEALTH

In the Ngorongoro Conservation Area (NCA), Tanzania, where wildlife and livestock interaction is intense, greater potential for intra- and interspecies disease transmission is expected. We assessed the prevalence of bovine tuberculosis in African buffalo (Syncerus caffer) residing on the valley floor of the crater in the NCA. Apparently healthy animals were randomly selected from herds in nine sites of the Ngorongoro Crater. Syncerus caffer buffalo herds were located using very high-frequency radio-aided rangers positioned in various observation points around the crater in the NCA. A total of 102 African buffalo from 16 herds were immobilized from the ground using a cocktail of 4-10 mg etorphine hydrochloride (M99) and 60-150 mg azaperone tartrate. The M99 was reversed using 10-25 mg diprenorphine hydrochloride depending on age of animals. An interferon gamma assay was performed on harvested plasma samples using sandwich enzyme linked immunosorbent assay. Of the 102 animals sampled, two (2%) African buffalo tested positive for bovine tuberculosis. These results corroborate those of the skin test done recently in cattle in the NCA. The presence of bovine tuberculosis in livestock and wildlife suggested the possibility of cross-species transmission of the disease, indicating the need for appropriate intervention measures.

Isolation and Potential for Transmission of Mycobacterium bovis at Human-livestock-wildlife Interface of the Serengeti Ecosystem, Northern Tanzania

Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), is a multihost pathogen of public health and veterinary importance. We characterized the M. bovis isolated at the human-livestock-wildlife interface of the Serengeti ecosystem to determine the epidemiology and risk of cross-species transmission between interacting hosts species. DNA was extracted from mycobacterial cultures obtained from sputum samples of 472 tuberculosis (TB) suspected patients and tissue samples from 606 livestock and wild animal species. M. bovis isolates were characterized using spoligotyping and Mycobacterial Interspersed Repetitive Units-Variable Tandem Repeats (MIRU-VNTR) on 24 loci. Only 5 M. bovis were isolated from the cultured samples. Spoligotyping results revealed that three M. bovis isolates from two buffaloes (Syncerus caffer) and 1 African civet (Civettictis civetta) belonged to SB0133 spoligotype. The two novel strains (AR1 and AR2) assigned as spoligotype SB2290 and SB2289, respectively, were identified from indigenous cattle (Bos indicus). No M. bovis was detected from patients with clinical signs consistent with TB. Of the 606 animal tissue specimens and sputa of 472 TB-suspected patients 43 (7.09%) and 12 (2.9%), respectively, yielded non-tuberculous mycobacteria (NTM), of which 20 isolates were M. intracellulare. No M. avium was identified. M. bovis isolates from wildlife had 45.2% and 96.8% spoligotype pattern agreement with AR1 and AR2 strains, respectively. This finding indicates that bTB infections in wild animals and cattle were epidemiologically related. Of the 24 MIRU-VNTR loci, QUB 11b showed the highest discrimination among the M. bovis strains. The novel strains obtained in this study have not been previously reported in the area, but no clear evidence for recent cross-species transmission of M. bovis was found between human, livestock and wild animals.

Prevalence of tuberculosis, brucellosis and trypanosomiasis in cattle in Tanzania: a systematic review and meta-analysis

A meta-analysis was performed to derive prevalence estimates for Brucella spp., Mycobacterium spp. and Trypanosoma spp. in cattle in Tanzania using data derived from a systematic review of zoonotic hazards in cattle production systems. Articles published before 2012 reporting prevalence and considered at least moderate in quality were included in the analysis. Results showed high heterogeneity between studies, with wide ranges in the reported prevalence: Brucella (0.3–60.8%), Mycobacterium (0.1–13.2%) and Trypanosoma (0.82–33.3%). Overall meta-analytic mean prevalence estimates were 8.2% (95% CI 6.5–10.2), 1.28% (95% CI 0.35–4.58) and 10.3% (95% CI 6.20–16.70) respectively, for Brucella spp., Mycobacterium spp. and Trypanosoma spp. Time and region were predictors of variability of Brucella spp. prevalence, while diagnostic test was a strong predictor of Mycobacterium spp. prevalence, with higher prevalence estimates given by skin tests compared with post-mortem inspection. None of the studied factors were associated with prevalence of Trypanosoma spp. The small sample sizes, range of study locations, study designs and diagnostics used, contributed to high variability among prevalence estimates. Larger and more robust prevalence studies are needed to adequately support risk assessment and management of animal and public health threats.

Risk factors associated with Mycobacterium bovis skin positivity in cattle and buffalo in Peshawar, Pakistan

A cross-sectional study was carried out to determine the prevalence of bovine tuberculosis (bTB) and associated risk factors in cattle and buffalo in Peshawar, Pakistan. Cattle and buffalo, randomly selected from all four towns of District Peshawar, were screened for bovine tuberculosis using comparative cervical intradermal tuberculin test (CCIT). For obtaining data on risk factors, sociodemographic condition, animal characteristics, and management, interviewer administered pretested questionnaire to animal owners. Multivariable logistic regression models were used to measure association between risk factors and comparative cervical intradermal tuberculin reactors. A total of 556 cattle and buffalo were screened for bovine tuberculosis. Out of 556 animals screened, 5.75 % (3.9-8.0 %) were found positive. The prevalence was higher in old animals (p = 0.001) as compared to younger animals. Prevalence also varied with source of animal (either raised on farm or purchased), stay of animals at night (indoor or outdoor), and herd size. Farmer's knowledge about transmission of TB from animals to human as well as signs and symptoms of TB was extremely low. Only 3.6 % farmers correctly stated the combination of three major symptoms of TB. Results of the study call for immediate intervention to control bTB in animals as well as its transmission to human population. Furthermore, it is suggested to emphasize on local epidemiology of bTB and husbandry practices of cattle and buffalo during the control program.

Screening putative antigens as stimulators in the Mycobacterium bovis interferon-gamma release assay for cattle

Bovine tuberculosis (BTB) represents not only a significant economic concern, but also an important public health problem. Currently, interferon-gamma (IFN-γ) release assays (IGRAs) are widely used as an adjunct to the tuberculin test (TST) for the diagnosis of BTB. A great number of international studies have demonstrated that the sensitivity of the IFN-γ assay, which uses purified protein derivatives (PPDs) as diagnostic reagents, is superior to that of the TST. However, there are concerns about its specificity, largely because of the cross reactivity of common antigens shared by pathogenic and non-pathogenic mycobacterial species. The use of pathogen-specific antigens theoretically offers the most effective way to improve the specificity of IGRAs. In this study, we evaluated the potential utility of 13 purified recombinant putative antigens, which are highly specific to the Mycobacterium tuberculosis complex, as diagnostic reagents in IGRAs. A CFP-10-ESAT-6 fusion protein (abbreviated CE) displayed the greatest potential, whereas four region of difference 2 (RD2) antigens, especially Rv1985c were identified as potential candidate antigens, and can be included in an IGRA cocktail, together with CE as stimulators in the IFN-γ release assay for the diagnosis of BTB.

Molecular characterization of Mycobacterium bovis isolates from pastoral livestock at Mikumi-Selous ecosystem in the eastern Tanzania

Domestic ruminants and Wild ungulates can act as reservoir hosts for Mycobacterium bovis, causative agent for bovine tuberculosis (BTB) in animals and man. Bovine tuberculosis (BTB) is endemic in pastoral livestock in Tanzania. There is lack of information on genotypic distribution of M. bovis in animals at wildlife-livestock interface areas and in wildlife conserved areas. The objectives of this study were to characterize and determine the spatial distribution of M. bovis isolates. Tissue samples from cattle and wildlife were cultured and analyzed using deletion typing and spoligotyping techniques. Eight (8.9%) M. bovis strains were isolated from cattle and confirmed by RD4 and RD9 polymerize chain reaction (PCR) assays. Spoligotype SB1467 was the dominant pattern 62.5% (n = 8) in infected animals, two isolates belonged to a newly reported type SB2190, and one isolate belonged to SB0133. The spoligotype patterns of SB1467 and SB0133 were closely related (96.9%) while SB2190 was less related (59.4%) to SB0133, the relatedness amongst spoligotypes were associated with spacer position 15. No M. bovis was isolated from hunted wild animals. The current study has identified a novel spoligotype SB2190. The current data suggest that wild animals in Mikumi-Selous ecosystem are at risk of acquiring M. bovis infection due to occasional interaction by sharing of pasture and water sources between wildlife and livestock. Integrated efforts by all stakeholders are crucial for controlling spread of tuberculosis at livestock/wildlife/human interface areas.

Comparison of bovine tuberculosis recurrence in Irish herds between 1998 and 2008

During the last several decades in Ireland, there has been substantial scientific progress in our understanding and related policy changes in the bovine tuberculosis (bTB) eradication programme. A range of performance measurements are routinely available, each highlighting a steadily improving situation in Ireland. However, recent research has highlighted an on-going problem of residual infection, contributing to recurrent breakdowns. In light of this general improvement, but also cognisant of residual infection, a critical evaluation of changes in effectiveness of managing recurrence is particularly valuable. Therefore, the objective of the study was to compare the herd-level risk of recurrence of bTB in Ireland between 1998 and 2008. A retrospective cohort study was carried out, using a Cox proportional-hazards model, to compare the risk of restriction recurrence in herds derestricted during 1998 and 2008. These herds were observed for up to 3 years from the end of the 'index restriction'. At the univariable level, 46.4% and 34.8% of study herds derestricted in 1998 and 2008, respectively, had a subsequent breakdown during the study period (χ(2)=70.6, P<0.001). In the multivariable analysis, there has been a significant reduction in bTB recurrence in Ireland, with 2008-derestricted herds being 0.74 times (95% confidence interval: 0.68-0.81) as likely to be restricted during the subsequent study period compared with 1998-derestricted herds. In the final Cox model, the rate of a future breakdown increased with increasing herd size, increasing number of standard reactors in the index restriction, increasing percentage of newly restricted herds within the District Electoral Division (DED) and if the herd had a previous bTB episode in the previous 5 years. The risk varied across herd type. The results from the current study provide further reassurance of an improved national situation, both in terms of limiting the establishment of new infection (bTB incidence) and in effectively clearing infection once detected (recurrence following derestriction). Recurrence of bTB requires effective implementation of multiple control strategies, focusing on identifying and removing residually infected cattle, and limiting environmental sources of infection, which in Ireland primarily relates to badgers.

Tuberculin screening of some selected Fulani lactating cows in North-Central Nigeria

The prevalence of mycobacterial infection among lactating Fulani cows was investigated in the Federal Capital Territory, Abuja and Kaduna State of Nigeria. Tuberculin testing using single comparative intradermal tuberculin test showed a 14.6 % positive, 4 % doubtful, and 81.4 % negative reactors. Mycobacterial infection was found to be present in the nomadic (constantly moving) and seminomadic (limited movement) management systems studied but management showed no significant effect on the prevalence of the disease. However, the prevalence was significantly higher in older age groups than the younger ones (P < 0.05).

Prevalence and significant geospatial clusters of bovine tuberculosis infection at livestock-wildlife interface ecosystem in Eastern Tanzania

Bovine tuberculosis (BTB) is an important neglected zoonosis that affects livestock, wildlife and human. A study to determine prevalence and geospatial clusters for BTB was conducted from June 2010 to March 2012 at livestock-wildlife interface areas (LWIA). A total of 1,288 cattle located in vicinity of Mikumi-Selous ecosystem Tanzania were tested. Single Intradermal Comparative Tuberculin Test and spatial scan statistic analysis were applied to establish the status of the disease and identify significant spatial BTB clusters. Overall individual prevalence was 3.7 % (n=1,288) (95 % CI=2.8-4.9) and 7.8 % (95 % CI=6.4-9.4) with cut-off of >4 and >2 mm, respectively. Villages with at least one reactor were 55.8 % (n=43). Reactivity was significantly higher in Mvomero and Kilosa districts compared with Kilombero and Ulanga districts (χ (2) =15.9; P<0.001). Significant spatial BTB clusters were revealed at 11 villages. BTB clustering was significant in Kilosa and Mvomero districts compared with Kilombero and Ulanga districts. There was overlap and aggregation of BTB clusters covering south and south-east of Kilosa district bordering Mikumi National Park (MNP) and Mvomero. Generally, clustering occurred around major rivers. The current study provides useful information on the dynamics and epidemiological status of BTB around the wildlife-livestock-human interface, it reveals that the wildlife are at risk of BTB from infected livestock. The study revealed hotspots for BTB that can be applied to guide implementation of participatory intervention at LWIA and control strategies in marginalised pastoralist communities. This study calls for similar studies in other Tanzania's LWIA for efficient intervention of BTB countrywide.