Distribution Of Bovine Tuberculosis Research Articles

Bacteriological and molecular characterization of Mycobacterium bovis isolates from tuberculous lesions collected among slaughtered cattle, Northwest Ethiopia

BackgroundIn Ethiopia, the distribution of bovine tuberculosis (BTB) has long been known and documented as a major problem of animal health. However, the burden of circulating M. bovis strains is poorly understood in the country. Therefore; this study aimed to identify and characterize the mycobacterial isolates responsible for BTB in Northwest Ethiopia.MethodsA cross-sectional study was conducted on tuberculous lesions that had been collected from slaughtered cattle between September 2018 to June 2019. Collected lesions were cultured and tested for tuberculous bacilli. The MPT64 assay and Genotype line probe assay (LPA) were used for identification of mycobacterial isolates, and region of deletion 4 (RD4) typing and spoligotyping were used to characterize the M. bovis strains.ResultsOf the total 1458 examined slaughtered cattle, only 62 (4.3, 95%CI; 0.0328–0.0542) had tuberculous lesions. The highest number of gross tuberculous lesions were observed from the lymph nodes of the thoracic cavity; at the mediastinal (40.3%, 25/62) and bronchial (22.6%, 14/62) lymph nodes. Of the 62 collected tuberculous lesions; 18 (29.0%) were culture positive for mycobacterium isolates, and only five isolates were confirmed for M. tuberculosis complex (MTBc) by the MPT64 assay and LPA. All the five MTBc isolates were positive for RD4 typing of M. bovis with a PCR product size of 446 bp, and no isolate was noticed to have M. tuberculosis. The detected M. bovis strains displayed five spoligotypes; with the common SB1176 and SB0133 M. bovis strains, although the two spoligotypes had not been previously reported.ConclusionThe present study shows that BTB in North Gondar, Ethiopia, is caused by M. bovis strains SB1176 and SB0033, with low frequency. Thus, the finding highlights the importance of continuous surveillance for mycobacterial strains in cattle populations.

The Distribution of Bovine Tuberculosis in Cattle Farms Is Linked to Cattle Trade and Badger-Mediated Contact Networks in South-Western France, 2007-2015.

Bovine tuberculosis (bTB), mainly caused by Mycobacterium bovis, can affect domestic and wild animals as well as humans. Identifying the major transmission mechanisms in an area is necessary for disease control and management. In this study, we aimed to evaluate the involvement of different types of contact in M. bovis transmission between cattle farms of south-western France between 2007 and 2015. We analyzed an empirical contact network of cattle farms as nodes, with known infection status and molecular types (16 circulated during the study period of which 14 affected only cattle and two both badgers and cattle). Edges were based on cattle trade data (T-edges) and on spatial neighborhood relationships between farms, either direct (P-edges) or badger-mediated, when two farms neighbored the same badger home range (B-edges), or two distinct but neighboring badger home ranges (D-edges). Edge types were aggregated so that the contact network contained only unique edges labeled by one or several edge types. The association between the contact network structure and bTB infection status was assessed using a non-parametric test, each molecular type being considered a marker of an independent epidemic. Using a logistic regression model, we estimated the contribution of each edge type to the probability for an edge originating from an infected farm to end at another infected farm. A total number of 1946 cattle farms were included in the study and were linked by 54,243 edges. Within this contact network, infected farms (whatever the molecular type) always belonged to the same component, suggesting the contact network may have supported bTB spread among those farms. A significant association between the pattern of bTB-infected farms and the structure of the contact network was observed when all the molecular types were simultaneously considered. The logistic regression model showed a significant association between M. bovis infection in direct neighbors of infected farms and the connection by T-, B- and D-edges, with odds-ratios of 7.4, 1.9, and 10.4, respectively. These results indicate a multifactorial M. bovis transmission between cattle farms of the studied area, with varying implication levels of the trade, pasture and badger networks according to the molecular type.

Genetic diversity and potential routes of transmission of Mycobacterium bovis in Mozambique.

Bovine tuberculosis is a zoonotic disease with largely unknown impact in Africa, with risk factors such as HIV and direct contact with animals or consumption of Mycobacterium bovis infected animal products. In order to understand and quantify this risk and design intervention strategies, good epidemiological studies are needed. Such studies can include molecular typing of M. bovis isolates. The aim of this study was to apply these tools to provide novel information concerning the distribution of bovine tuberculosis in cattle in Mozambique and thereby provide relevant information to guide policy development and strategies to contain the disease in livestock, and reduce the risk associated with transmission to humans. A collection of 178 M. bovis isolates was obtained from cattle in Mozambique. Using spoligotyping and regions of difference analysis, we classified the isolates into clonal complexes, thus reporting the first characterisation of M. bovis strains in this region. Data from MIRU-VNTR typing was used to compare isolates from a number of African countries, revealing a deeply geographically structured diversity of M. bovis. Eastern Africa appears to show high diversity, suggesting deep evolution in that region. The diversity of M. bovis in Africa does not seem to be a function of recent importation of animals, but is probably maintained within each particular region by constant reinfection from reservoir animals. Understanding the transmission routes of M. bovis in Mozambique and elsewhere is essential in order to focus public health and veterinary resources to contain bovine tuberculosis.

Tuberculosis in water buffalo (Bubalus bubalis) in the Baixo Araguari Region, Amapá, Brazil

Water buffalo are of great economic importance in Brazilian Amazonia, which has the largest herd in Brazil. Bovine tuberculosis caused by Mycobacterium bovis is a zoonotic disease that results in severe losses to water buffalo production. Although the disease has already been described in the country, data on the occurrence and distribution of bovine tuberculosis in water buffalo in Brazil is very scarce. The aim of this study was to determine the frequency of bovine tuberculosis in water buffalo in the Baixo Araguari River region of Amapá, Brazil. Thirty herds, randomly selected from the 41 herds of water buffalo in the region, were sampled. From those herds, 212 randomly selected water buffalo were subjected to the comparative tuberculin skin test. The proportion of Baixo Araguari River region herds that were positive for bovine tuberculosis was 50.0% (95% CI 31.3% to 68.7%) and the proportion of animals that were positive was estimated to be 14.8% (95% CI 7.8% to 21.9%). Our results show that bovine tuberculosis is spread widely among water buffalo in the Baixo Araguari River region, which suggests that measures to control the disease should be undertaken in the region.

Occurrence and Distribution of bovine tuberculosis (Mycobacterium bovis) in Slaughtered cattle in the abattoirs of Bauchi State, Nigeria.

Aim:This study was aimed to determine the prevalence of bovine tuberculosis (bTB) in slaughtered cattle in Bauchi State, Nigeria. The cause (s) of grossly suspected bTB lesions encountered at the abattoirs during post-mortem (PM), as whether due to Mycobacterium bovis alone or together with other acid fast bacilli (AFB).Materials and Methods:A cross-sectional abattoir based study was conducted on 800 cattle slaughtered in the Northern, Central and Southern zonal abattoirs of Bauchi State, Nigeria, from June to August 2013; using PM meat inspection, Ziehl-Neelsen staining (ZN) and confirmatory polymerase chain reaction (PCR) techniques.Results:The occurrence of bTB lesions from the organs of slaughtered cattle in Bauchi State, showed that the lungs had the highest number of suspected tissues 65 (54.20%), followed by the lymph nodes 28 (23.30%) while the heart, liver, spleen, intestines and mammary glands had the other 8.3%, 6.7%, 5.0%, 1.7%, and 0.8%, suspected tissues respectively. By ZN microscopic staining all 100% (2/2) of the intestines were positive for bTB, followed by the heart with 50% (5/10), then the lungs 29.23% (19/65); while the liver, lymph nodes, and spleen had 25%, 21.43% and 16.67% respectively were tested positive for bTB. It was only the mammary gland that tested negative for bTB in all the suspected tissues sampled. By PCR, the intestines had the highest positive bTB with 100% (2/2), followed by the liver with 12.5% (1/8), and then the lungs with 7.8% (5/65). The lymph nodes had 7.14% (2/28) tissues that tested positive for bTB. However, the spleen, heart and mammary gland were all tested negative with 0%; indicating that the false positive for bTB detected by ZN were confirmed by PCR. While based on the location of the abattoirs in the three senatorial zones of Bauchi State, Bauchi zonal abattoir had the highest number of suspected bTB cases 75 (62.50%), followed by Katagum zonal slaughter house with 32 (26.7%) and then Misau with 13 (10.8%). By the ZN staining technique, there were 25 (33.33%) positivity in Bauchi Zonal abattoir, while Katagum and Misau abattoirs had 9 (28.13%) and 1 (7.72%) positive respectively. By the PCR technique, 9 (12.00%), 1 (3.13%) and 0 (0.00%) positive cases were recorded for Bauchi, Katagum and Misau abattoirs respectively.Conclusion:The present study estimated the prevalence rate of bTB in Bauchi State, using PM, ZN and PCR techniques at 15.0%, 29.16% and 8.33%, respectively. Bovine TB lesions found at PM were not all due to M. bovis alone, as other MTBC and AFB organisms may cause bTB-like lesions that were excluded by PCR specific primers. The prevalence of bTB was higher in Bauchi abattoir that supplies larger population of the state with beef. These findings also demonstrate the urgent need for public health authorities in the state to intervene in the control of the zoonotic bTB.

The spatial distribution of bovine tuberculosis in England

ABSTRACTBovine tuberculosis (bTB) is a major cattle disease affecting the livestock industry in England and Wales. While bTB data have been presented in many forms and some mapping has been undertaken both in government and academia, relatively little research has been conducted on the spatial distribution of bTB in the UK by geographers. Using a location quotient (LQ) methodology to map the incidence of bTB in England over the last decade, this article identifies a disease core in the South West and West Midlands. It also shows that the disease has become more widespread in northern and eastern regions since the 1990s and has emerged in previously unaffected areas. These findings have important implications for the development of policy to tackle the bTB problem.

La utilidad de los sistemas de información geográfica en la predicción de la distribución regional de la tuberculosis bovina

A growing need exists for low cost systems to predict the status of diseases within geographical regions. The purpose of this research was to evaluate the usefulness of geographic information systems (GIS) and geostatistical (i.e.: Kriging) methods in predicting the prevalence and distribution of bovine tuberculosis (BTB) in the state of Jalisco, Mexico, based on a sample of herds. Two-thousand two-hundred and eighty-seven herds were electronically selected at random from the Jalisco´s State Commission for the Control and Eradication of Tuberculosis (COEETB) data base. Three different approaches (i.e.: a personal Global Positioning System [GPS], Mexico's National Institute for Statistics Geography and Informatics [INEGI]'s data base, and the Google Earth software) were used to identify the spatial location of each herd. Kriging, from ArcView Geostatistical Analyst was used to predict the prevalence of BTB. The efficacy of this prediction was determined by comparing two maps, one based on our 2,287 sample of herds and the map showing the distribution of Jalisco's total 48,766 herds. Similarity of BTB regional distribution in both maps shows that Kriging and geostatistics is an excellent tool to predict BTB distribution with major potential savings.

A preliminary investigation of tuberculosis and other diseases in African buffalo (<i>Syncerus caffer</i>) in Queen Elizabeth National Park, Uganda

A survey to determine the prevalence of bovine tuberculosis caused by Mycobacterium bovis and certain other infectious diseases was conducted on 42 free-ranging African buffaloes, (Syncerus caffer) from May to June 1997 in the Queen Elizabeth National Park, Uganda. Using the gamma interferon test, exposure to M. bovis was detected in 21.6% of the buffaloes. One dead buffalo and an emaciated warthog (Phacochoerus aethiopicus) that was euthanased, were necropsied; both had miliary granulomas from which M. bovis was isolated. None of the buffaloes sampled in Sector A of the park, which has no cattle interface, tested positive for bovine tuberculosis (BTB) exposure. The prevalence and distribution of BTB does not appear to have changed significantly since the 1960s, but this may be due to fluxes in the buffalo population. Serological testing for foot-and-mouth disease (FMD) demonstrated positive exposure of 57.1% of the buffaloes sampled, with types A, O and SAT 1-3, which is the first known report of FMD antibodies to A and O types in free ranging African buffaloes. Foot-and-mouth disease virus types SAT 1 and SAT 3 were isolated from buffalo probang samples. Two percent of the buffaloes had been exposed to brucellosis. None of the buffaloes tested had antibodies to rinderpest, leptospirosis or Q fever.