Occurrence of trypanosome infections in cattle in relation to season, livestock movement and management practices of Maasai pastoralists in Northern Tanzania.

African animal trypanosomosis (AAT) is a parasitic disease considered to be one of the greatest constraints to cattle production in Tanzania. There is insufficient information on seasonal occurrence of AAT and management practices in Monduli District of the Maasai Steppe ecosystem to guide and prioritize AAT control programs. A cross-sectional survey was undertaken in 10 randomly selected villages of Monduli District. Information on seasonal animal movements, including wildlife interaction, and AAT management practices was gathered using a standardized questionnaire with 130 pastoralists. Blood samples were collected from a total of 960 cattle, in wet and dry seasons. An entomological survey was also undertaken in the dry season. Polymerase chain reaction targeting the internal transcribed spacer 1 (ITS1) was used for parasite identification in cattle blood and in tsetse flies. The overall apparent prevalence of AAT in cattle was 5.8% (95% CI of 4.1-8.3) and 4.2% (95% CI of 2.7-6.3) during wet and dry reasons, respectively. Trypanosoma vivax was the most common species identified in cattle. All tsetse flies (n = 426) collected were trapped in Esilalei village which is in close proximity to Lake Manyara National Park. Tsetse fly infection status was determined to be 7.0%; (CI 95% of 4.9-9.8%) with nearly 50% of infections due to T. congolense. All 130 cattle owners reported that they could easily recognize AAT and the majority (75%) identified the most prominent clinical signs. Nearly all owners (98.5%) identified that tsetse flies were responsible for AAT transmission. All cattle owners (100%) reported the use of trypanocides for AAT treatment, while 2.3% reported to also use herbal medicine. The trypanocides, Novidium® and Berenil®, were the most frequently reported commercial drugs and were used by 42% of cattle owners. Vector control by hand spraying was reported by the majority (90.8%) of cattle owners, while dipping and deployment of insecticide-impregnated targets were reported by few cattle owners (16.2% and 5.4%, respectively). The majority of cattle owners (83.1%) reported to move cattle away from home villages during the dry season with many migrating to areas in close proximity to wildlife parks. This study confirms the presence of circulating pathogenic trypanosomes in tsetse flies which continue to pose a threat to Maasai cattle. The seasonal movement of cattle during the dry season was associated with more clinical cases of cattle trypanosomosis. This study demonstrates the need to strengthen surveillance and control strategies for AAT.

Climate change and cattle vector-borne diseases: Use of participatory epidemiology to investigate experiences in pastoral communities in Northern Tanzania.

Climate change is predicted to increase incidence of vector-borne diseases in humans, however, little is known about the impact of such diseases in livestock. In the absence of historical data with which to examine the inter-relation between climate and disease, participatory epidemiological (PE) methods were used with Maasai pastoralists of Monduli District, northern Tanzania to establish local observations on two major vector-borne diseases of cattle, namely East Coast fever (ECF) and African animal trypanosomiasis (AAT). Data collection involving gender segregated groups (10 men groups and 9 women groups) occurred in 10 randomly selected villages between November 2014 and March 2015. ECF and AAT were ranked amongst the top 5 most important cattle diseases with strong agreement across informant groups (Kendall's W=0.40 for men and 0.45 for women; p<0.01). Matrix scoring for both men and women groups confirmed that Masaai easily recognize these diseases. All groups associated ECF with the wet and cool dry seasons. AAT was more variable throughout the year, with more cases reported in the long dry season. Likewise, pastoralists reported differences in seasonal occurrence of disease vectors (Rhipicephalus appendiculatus and Glossina spp.) by village. Comparing 2014-1984, participant groups consistently reported declines in rainfall, vegetation cover and quality pasture, as well as increases in severe droughts. Experiences with ECF/AAT and vector abundance between these time periods was more variable across villages, and likely relates to changes in climate and animal management practices over the last 30 years. This baseline study is the first to document the inter-relation between climate and cattle vector-borne disease from the pastoralist perspective. Findings from this study reveal a complex interplay between human, animal and environmental factors, understanding of which is urgently required to devise approaches to mitigate effects of climate change in these vulnerable areas.

Seasonal occurrence of Theileria parva infection and management practices amongst Maasai pastoralist communities in Monduli District, Northern Tanzania.

Theileria parva causes an economically devastating tick-borne disease called East Coast fever (ECF), which affects cattle in central, eastern and southern Africa. Determination of seasonal infection rates for T. parva is crucial for epidemiological understanding and for strengthening ECF management practices. However, this information is lacking for most pastoralist areas with high livestock density, such as the Monduli District in the Maasai steppe, northern Tanzania. A cross-sectional study was carried out to estimate the prevalence of T. parva in wet and dry seasons, and to assess understanding of management practices associated with T. parva amongst pastoralists' cattle. A total of 960 cattle owned by 130 pastoralists were randomly selected from ten study villages in each season and blood samples analysed for T. parva prevalence using a nested polymerase chain reaction (PCR). Seroprevalence for T. parva in the wet season was assessed using an enzyme-linked-immunosorbent assay (ELISA). Information on relevant management practices was gathered using a standardized questionnaire. Multivariable logistic regression was used to evaluate the association between T. parva parasitaemia and animal, farm and village-level factors. The prevalence of T. parva parasitaemia was 15.9% (95% CI=0.13-0.19) and 31.6% (95% CI=0.28-0.36) in wet and dry seasons, respectively. All cattle were sero-positive. T. parva parasitaemia was significantly associated with age of the animal, sampling season, and study village. All 130 cattle owners interviewed (100%) reported that they could easily recognise ECF and the vast majority (97.7%) identified swollen lymph nodes as the most prominent sign. At least 70% reported to understand the involvement of R. appendiculatus in ECF transmission. The use of both commercial drugs and herbal medicines for ECF treatment was reported by 54.6% of cattle owners. Among commercial drugs reported, the most commonly used was alamycin 300mg/ml (oxytetracycline dehydrates). Tick control by hand spraying was reported by the majority (90.8%) of cattle owners and less than half (45.4%) reported to vaccinate their cattle. This research provides evidence of widespread T. parva infection across Monduli District, and baseline information on seasonal occurrence. This information can assist the planning of more appropriate control strategies in pastoralist communities both now and into the future as predicted climatic changes progress in the region and potentially influence ECF occurrence and transmission.