Molecular epidemiology of bovine tuberculosis in Tanzania

A study on molecular epidemiology of bovine tuberculosis in man and cattle in Tanzania was carried with two components. The first component was based on field investigation of tuberculosis in cattle and man in Arusha region, in the north and in the Usangu Plains in the Southern Highlands of Tanzania. The second component involved laboratory analysis of mycobacterialstrains acquired from field study by both conventional and molecular biology techniques.In field work, a total of 6383 cattle were tuberculin tested, and 911 (14.3%) were classified as reactors. 841 of 6383 cattle examined were destine for slaughter and 225 (26.8%) were found to have visible lesions. A total of 1719 pooled lymph node samples collected from slaughter cattle in the study area (Arusha n=1068 and the Usangu Plains n=651) were cultured and 4.0% yielded mycobacteria. 80 of the samples from the Usangu Plains came from cattle classified as reactors (Table 3.9), while samples from Arusha had no accompanying tuberculin test results. Among the isolates 72.6% were classified as M. bovis and the rest as atypical mycobacteria. Of the 805 milk samples cultured (14% were from reactor cattle), only two (0.3%) yielded M. bovis, the remaining 36 isolates were atypical mycobacteria (Table 3.10). Its only two isolates of atypical mycobacteria which came from reactor cattle.Regarding human specimens, a total of 53 lymph node biopsies were submitted for culture and 21 (39.6%) were positive for mycobacteria. Six isolates were identified as M. bovis, and the remaining 15 were M. tuberculosis. Of 96 sputum samples which were collected, mycobacteria species were recovered from 23 but only one (4.3%) was classified as M. bovis. Sixteen (69.1%) isolates were identified as M. tuberculosis, and the rest were atypical mycobacteria. Epidemiological data revealed that M. bovis was more prevalent in people with cattle contact than in other occupations (Table 3.13)The IS986 and mtpAQ multiplex PCR developed in the course of this study was able to differentiate M. bovis from M. tuberculosis. DNA fingerprinting of all the strains cultured was carried out using restriction fragment length polymorphism (RFLP) and spoligotyping techniques. The copy number of IS986 amongst strains of M. bovis from cattle ranged from one to six, while those from man had five to 15. There was similarity of DNA fingerprints among some of the strains from cattle and man as determined by the three typing techniques (Figures 6.2, 6.5 and 6.9). M. tuberculosis strains were found to belong to three clusters by IS986 RFLP, with one cluster containing over 60% of the strains.Intersegment PCR, a molecular typing technique developed in the current study was able to differentiate strains but the results were influenced by the concentration of template DNA. A DNA fragment apparently found only in M. bovis and absent in M. tuberculosis and other mycobacteria was identified by the RAPD PCR techniques. This fragment was cloned, sequenced and its DNA sequence was found to match a M. tuberculosis cosmid, which also matched rfbE gene of Yersinia enterocolitica. Specificity testing revealed hybridization to M. tuberculosis as well.The findings of the above studies have showed the existence of M. bovis infection in man and cattle in Tanzania. The study has also shown the zoonotic importance of infection in the two populations which necessitates a veterinary/medical approach to the control of the disease in Tanzania. Furthermore, it has been shown that molecular biology techniques are essential epidemiological tools in studies of zoonotic conditions such as tuberculosis. The study was unable to find a specific DNA element for M. bovis. This observation concurs with others which have found 100% homogeneity between species of the M. tuberculosis complex

Seroprevalence and risk factors for human brucellosis in agro-pastoral areas in Tanzania

Background: Brucellosis is an endemic zoonosis in Tanzania. This study was conducted to investigate the seroprevalence of human brucellosis and its risk factors in agro-pastoral areas in Morogoro Region, Tanzania. Methods: Questionnaire survey and blood sampling were conducted from January to February 2018 at four villages. Anyone living in the villages and wished to participate were involved. Competitive ELISA was used for diagnosis. Risk factor analysis for sero-positivity in human and analysis for the association of sero-positivity between cattle and human within each farm were conducted, using the data of farm-level bovine brucellosis status from our bovine brucellosis research performed in 2016. Results: The seroprevalence was 33.3% (44/132). In univariable analysis, the Maasai were significantly more sero-positive (56.5%) than other tribes (28.4%) (OR = 3.23, 95% CI: 1.28–8.41). Drinking raw milk was a risk factor in both univariable and multivariable analyses (OR = 3.97, 95% CI: 1.61–10.20). A negative association between sero-positivity in cattle and human within each farm was found (p<0.01). The Maasai performed more risk-taking behaviours for human infection than other tribes: drinking raw milk (p<0.01) or blood (p<0.01) and helping delivery of cattle with bare hands (p=0.03). Conclusions: The Maasai were at high risk of human brucellosis. More detailed survey and educational interventions are urgently needed

Controlling human rabies: the development of an effective, cheap and locally made Passive Cooling Device for storing thermotolerant animal rabies vaccines

Thermotolerant vaccines greatly improved the reach and impact of large-scale vaccination programs to eliminate diseases such as smallpox, polio and rinderpest. A recent study demonstrated that the potency of the Nobivac® Canine Rabies vaccine was not impacted following experimental storage at 30 °C for three months. We conducted a study to develop a passive cooling device (PCD) that could store thermotolerant vaccines under fluctuating subambient temperatures. Through a participatory process with local communities in Northern Tanzania, we developed innovative PCD designs for local manufacture. A series of field experiments were then carried out to evaluate the effectiveness of five PCDs for vaccine storage under varying climatic conditions. Following iterative improvement, a final prototype “Zeepot Clay” was developed at the cost of US$11 per unit. During a further field-testing phase over a 12-month period, the internal temperature of the device remained below 26 °C, despite ambient temperatures exceeding 42 °C. Our study thus demonstrated that locally designed PCDs have utility for storing thermotolerant rabies vaccines at subambient temperatures. These results have application for the scaling up of mass dog vaccination programs in low-and-middle income countries, particularly for hard-to-reach populations with limited access to power and cold-chain vaccine storage

Educating pastoralists and extension officers on diverse livestock diseases in a changing environment in Tanzania

East African pastoralists and their livestock are vulnerable to alterations in resource availability and disease transmission and frequently face poor access to livestock health services. Government veterinarians tasked with guiding health services must prioritize livestock health risks and allocate limited resources across disparate ecosystems with different disease threats. To identify livestock diseases of concern and strategies for improving herd health and resilience, we conducted community focus groups with pastoralists and interviewed pastoralist household leaders, village extension officers, and government veterinary officials in south-central Tanzania, an area experiencing rapid population growth and environmental change. All participants discussed pastoralist access to livestock health services, livestock disease priorities, and means to improve livestock health. Perceptions of diseases of importance differed among pastoralists, extension officers, and government veterinarians. Spatial differences in diseases of concern among study area pastoralists emphasized the need for locally adaptable livestock health service delivery. Although pastoralist strategies to improve livestock health differed by ethnic group, many pastoralists as well as extension officers and government veterinarians identified livestock health education and training for pastoralists and extension officers as a critical need. Policies designed at the regional, rather than the local, level may not reflect the disease concerns of the entire area. To effectively address veterinary health problems and make livestock herds more resilient to environmental change, conditions at the local level must be considered. Education targeted to pastoralist households and extension officers could achieve greater flexibility in the livestock health system and provide more reliable information about local conditions for governmental policymakers

Seasonal movements and habitat use of African buffalo in Ruaha National Park, Tanzania.

BACKGROUND:Assessing wildlife movements and habitat use is important for species conservation and management and can be informative for understanding population dynamics. The African buffalo (Syncerus caffer) population of Ruaha National Park, Tanzania has been declining, and little was known about the movement, habitat selection, and space use of the population, which is important for understanding possible reasons behind the decline. A total of 12 African buffalo cows from four different herds were collared with satellite transmitters. Movements were assessed over 2 years from 11 animals. RESULTS:The space use of the individual collared buffaloes as an approximation of the 95% home range size estimated using Brownian bridge models, ranged from 73 to 601 km2. The estimated home ranges were larger in the wet season than in the dry season. With the exception of one buffalo all collared animals completed a wet season migration of varying distances. A consistent pattern of seasonal movement was observed with one herd, whereas the other herds did not behave the same way in the two wet seasons that they were tracked. Herd splitting and herd switching occurred on multiple occasions. Buffaloes strongly associated with habitats near the Great Ruaha River in the dry season and had little association to permanent water sources in the wet season. Daily movements averaged 4.6 km (standard deviation, SD = 2.6 km), with the longest distances traveled during November (mean 6.9 km, SD = 3.6 km) at the end of the dry season and beginning of the wet season. The shortest daily distances traveled occurred in the wet season in April-June (mean 3.6 km, SD = 1.6-1.8 km). CONCLUSION:The Great Ruaha River has experienced significant drying in the last decades due to water diversions upstream, which likely has reduced the suitable range for buffaloes. The loss of dry season habitat due to water scarcity has likely contributed to the population decline of the Ruaha buffaloes

Lay attitudes and misconceptions and their implications for the control of brucellosis in an agro-pastoral community in Kilombero district, Tanzania

Funding: The research for this paper was carried out within the framework of the DELTAS Africa Initiative [Afrique One-ASPIRE /DEL-15-008] (to CMM). Afrique One-ASPIRE is funded by a consortium of donor including the African Academy of Sciences (AAS) Alliance for Accelerating Excellence in Science in Africa (AESA), the New Partnership for Africa’s Development Planning and Coordinating (NEPAD) Agency, the Wellcome Trust [107753/A/15/Z] and the UK government. The authors were funded by Afrique One ASPIRE to conduct this study.Brucellosis is a priority zoonotic disease in Tanzania that causes ill-health in people and affects livestock productivity. Inadequate awareness and behavior risking transmission can impede control efforts. We conducted a cross-sectional survey of 333 livestock owners in three villages in the Kilombero district, Tanzania, to understand their awareness, knowledge and behavior associated with brucellosis. Six Focus Group Discussions (FGDs), two in each village, were conducted, as well as an additional FGD with male herders from one of the villages. Factors associated with knowledge on brucellosis, food consumption and animal husbandry behavior risking transmission of this disease, were identified using generalized linear models. Predictors for knowledge of brucellosis were being male and having a higher educational level, while age was positively associated with a higher level of knowledge. Faith and ethnicity were associated with the performance of practices risking transmission. Following traditional religion and belonging to the Wamaasai ethnicity significantly increased the odds of carrying out these practices. Qualitative analysis gave insight into risk practices and reasoning. Of the 333 respondents, 29% reported that they had experienced abortions in their herds, 14% witnessed retained placentas, and 8% had seen still-births in their cattle within the previous year. However, survey results also showed that only 7.2% of participants had heard about brucellosis as a disease in livestock. Of those who had heard about brucellosis in livestock, 91% associated abortions with it and 71% knew that humans can get infected through raw milk consumption. People overwhelmingly attributed symptoms and transmission of brucellosis in livestock to infection with trypanosomiasis and to supernatural reasons instead. In the community, consumption of raw milk was valued and handling of aborted material was not considered a risk for infection. This agro-pastoralist community holds on to long-held beliefs and practices and lacks understanding of the biomedical concept of brucellosis. Transmission routes and symptoms of brucellosis in humans and livestock are completely unknown. The disparity between risk perception and actual transmission risk related to animal handling and consumption of animal products presents a challenge for disease awareness communication. This study recommends focused community engagement and sensitization to address the limited awareness and misconceptions among agro-pastoralists.Publisher PDFPeer reviewe

Health and demographics of African buffalo (Syncerus caffer) in Ruaha National Park, Tanzania

Presented at the 9th international wildlife ranching symposium: wildlife - the key to prosperity for rural communities, held on 12-16 September 2016 at Hotel Safari & the Safari Court, Windhoek, Namibia in conjuction with the IUCN 2nd African Buffalo Symposium.The African buffalo (Syncerus caffer) population of Ruaha National Park may be in decline. Seasonal drying of the park's water source due to upstream irrigation may have caused loss of dry season habitat, increased pressure on remaining water sources, and possibly increased contact between wildlife and livestock at the park borders. The Health for Animals and Livelihood Improvement (HALI) project and Ruaha National Park are collaborating to investigate the health and population status of the African buffaloes. Between 2011 and 2015, this partnership resulted in testing 30 young and 25 adult African buffaloes for bovine tuberculosis (2011, 2014-15), conducting 4 dry season demographic surveys and herd level parasite screenings (2011, 2013-15), and conducting one aerial population survey in collaboration with the Tanzania Wildlife Research Institute (2013). In 2014-15, 12 adult female buffaloes were collared with satellite GPS collars to learn more about the seasonal movements, habitat preferences, and herd dynamics of Ruaha's buffalo herds. The research has shown that bovine tuberculosis and brucellosis is present in the buffalo population, that the population number appear to be reduced since the last total count in 2004, that the herd composition and seasonal movements may be influenced by rainfall, and the herd level gastrointestinal parasite counts generally are low. The data generated in this study will be used to inform management and conservation of Ruaha National Park's buffaloes

Mycobacteria in Terrestrial Small Mammals on Cattle Farms in Tanzania

The control of bovine tuberculosis and atypical mycobacterioses in cattle in developing countries is important but difficult because of the existence of wildlife reservoirs. In cattle farms in Tanzania, mycobacteria were detected in 7.3% of 645 small mammals and in cow's milk. The cattle farms were divided into “reacting” and “nonreacting” farms, based on tuberculin tests, and more mycobacteria were present in insectivores collected in reacting farms as compared to nonreacting farms. More mycobacteria were also present in insectivores as compared to rodents. All mycobacteria detected by culture and PCR in the small mammals were atypical mycobacteria. Analysis of the presence of mycobacteria in relation to the reactor status of the cattle farms does not exclude transmission between small mammals and cattle but indicates that transmission to cattle from another source of infection is more likely. However, because of the high prevalence of mycobacteria in some small mammal species, these infected animals can pose a risk to humans, especially in areas with a high HIV-prevalence as is the case in Tanzania

Epidemiology of Leptospirosis in Africa: A Systematic Review of a Neglected Zoonosis and a Paradigm for 'One Health' in Africa.

Leptospirosis is an important but neglected bacterial zoonosis that has been largely overlooked in Africa. In this systematic review, we aimed to summarise and compare current knowledge of: (1) the geographic distribution, prevalence, incidence and diversity of acute human leptospirosis in Africa; and (2) the geographic distribution, host range, prevalence and diversity of Leptospira spp. infection in animal hosts in Africa. Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, we searched for studies that described (1) acute human leptospirosis and (2) pathogenic Leptospira spp. infection in animals. We performed a literature search using eight international and regional databases for English and non-English articles published between January 1930 to October 2014 that met out pre-defined inclusion criteria and strict case definitions. We identified 97 studies that described acute human leptospirosis (n = 46) or animal Leptospira infection (n = 51) in 26 African countries. The prevalence of acute human leptospirosis ranged from 2 3% to 19 8% (n = 11) in hospital patients with febrile illness. Incidence estimates were largely restricted to the Indian Ocean islands (3 to 101 cases per 100,000 per year (n = 6)). Data from Tanzania indicate that human disease incidence is also high in mainland Africa (75 to 102 cases per 100,000 per year). Three major species (Leptospira borgpetersenii, L. interrogans and L. kirschneri) are predominant in reports from Africa and isolates from a diverse range of serogroups have been reported in human and animal infections. Cattle appear to be important hosts of a large number of Leptospira serogroups in Africa, but few data are available to allow comparison of Leptospira infection in linked human and animal populations. We advocate a 'One Health' approach to promote multidisciplinary research efforts to improve understanding of the animal to human transmission of leptospirosis on the African continent

Comparing methods of assessing dog rabies vaccination coverage in rural and urban communities in Tanzania

Rabies can be eliminated by achieving comprehensive coverage of 70% of domestic dogs during annual mass vaccination campaigns. Estimates of vaccination coverage are, therefore, required to evaluate and manage mass dog vaccination programs; however, there is no specific guidance for the most accurate and efficient methods for estimating coverage in different settings. Here, we compare post-vaccination transects, school-based surveys, and household surveys across 28 districts in southeast Tanzania and Pemba island covering rural, urban, coastal and inland settings, and a range of different livelihoods and religious backgrounds. These approaches were explored in detail in a single district in northwest Tanzania (Serengeti), where their performance was compared with a complete dog population census that also recorded dog vaccination status. Post-vaccination transects involved counting marked (vaccinated) and unmarked (unvaccinated) dogs immediately after campaigns in 2,155 villages (24,721 dogs counted). School-based surveys were administered to 8,587 primary school pupils each representing a unique household, in 119 randomly selected schools approximately 2 months after campaigns. Household surveys were conducted in 160 randomly selected villages (4,488 households) in July/August 2011. Costs to implement these coverage assessments were $12.01,$66.12, and $155.70 per village for post-vaccination transects, school-based, and household surveys, respectively. Simulations were performed to assess the effect of sampling on the precision of coverage estimation. The sampling effort required to obtain reasonably precise estimates of coverage from household surveys is generally very high and probably prohibitively expensive for routine monitoring across large areas, particularly in communities with high human to dog ratios. School-based surveys partially overcame sampling constraints, however, were also costly to obtain reasonably precise estimates of coverage. Post-vaccination transects provided precise and timely estimates of community-level coverage that could be used to troubleshoot the performance of campaigns across large areas. However, transects typically overestimated coverage by around 10%, which therefore needs consideration when evaluating the impacts of campaigns. We discuss the advantages and disadvantages of these different methods and make recommendations for how vaccination campaigns can be better monitored and managed at different stages of rabies control and elimination programs