A cross-sectional survey to establish Theileria parva prevalence and vector control at the wildlife-livestock interface, Northern Tanzania.

East Coast fever (ECF) in cattle is caused by the protozoan parasite Theileria parva, transmitted by Rhipicephalus appendiculatus ticks. In cattle ECF is often fatal, causing annual losses >$500 million across its range. The African buffalo (Syncerus caffer) is the natural host for T. parva but the transmission dynamics between wild hosts and livestock are poorly understood. This study aimed to determine the prevalence of T. parva in cattle, in a 30 km zone adjacent to the Serengeti National Park, Tanzania where livestock and buffalo co-exist, and to ascertain how livestock keepers controlled ECF and other vector-borne diseases of cattle. A randomised cross-sectional cattle survey and questionnaire of vector control practices were conducted. Blood samples were collected from 770 cattle from 48 herds and analysed by PCR to establish T. parva prevalence. Half body tick counts were recorded on every animal. Farmers were interviewed (n = 120; including the blood sampled herds) using a standardised questionnaire to obtain data on vector control practices. Local workshops were held to discuss findings and validate results. Overall prevalence of T. parva in cattle was 5.07% (CI: 3.70-7.00%), with significantly higher prevalence in older animals. Although all farmers reported seeing ticks on their cattle, tick counts were very low with 78% cattle having none. Questionnaire analysis indicated significant acaricide use with 79% and 41% of farmers reporting spraying or dipping with cypermethrin-based insecticides, respectively. Some farmers reported very frequent spraying, as often as every four days. However, doses per animal were often insufficient. These data indicate high levels of acaricide use, which may be responsible for the low observed tick burdens and low ECF prevalence. This vector control is farmer-led and aimed at both tick- and tsetse-borne diseases of livestock. The levels of acaricide use raise concerns regarding sustainability; resistance development is a risk, particularly in ticks. Integrating vaccination as part of this community-based disease control may alleviate acaricide dependence, but increased understanding of the Theileria strains circulating in wildlife-livestock interface areas is required to establish the potential benefits of vaccination.

A tsetse Glossina pallidipes harbors the pathogenic trypanosomes circulating in Liwale district, Tanzania.

African Animal Trypanosomiasis (AAT) is among several constraints hindering development of the livestock sector in Tanzania. A survey was conducted in Liwale district located in southern Tanzania in 2013 to determine the population density of Glossina species, distribution pattern and Trypanosome species infection rate in tsetse flies. A total of 200 flies were collected from the study area and three Glossina species were identified. The proportional abundance of all trapped flies was 90% (180) for Glossina pallidipes, 6% (12) for G. brevipalpis and 4% (8) for G. m. morsitans with apparent densities (fly/trap/day - FTD) of 0.44. Higher density of Glossina pallidipes was observed in villages closer to than those far from the Selous game reserve. Trypanosomes were detected and identified by microscopy and ITS1 polymerase chain reaction (PCR) assay on DNA purified from 200 flies. Glossina pallidipes was the only fly found infected by three Trypanosoma species, namely T. vivax (60%), T. simiae (10%) and T. brucei (30%) with an overall infection rate of 10% (20/200). A higher proportion of trypanosome infections were observed in female tsetse flies than in males. Results of this study show that G pallidipes is the major Glossina species harboring pathogenic trypanosomes in Liwale district and that the Selous game reserve is a potential reservoir of trypanosomes in terms of parasite abundance and species diversity.

The role of domestic animals in the epidemiology of human African trypanosomiasis in Ngorongoro conservation area, Tanzania.

BACKGROUND: Trypanosomiasis is a neglected tropical disease caused by the trypanosome parasite and transmitted by the tsetse fly vector. In Sub-saharan Africa, both the human and animal variants of the disease are a great obstacle towards agriculture, development, and health. In order to better understand and therefore combat Trypanosomiasis, characterizing disease hotspots across species is critical. METHODS: In this study, 193 samples from cattle, sheep, and goats were collected from eight sites. Samples were taken from animals belonging mostly to Maasai herdsmen in the Ngorongoro Crater Conservation Area (NCA) and analysed for the presence of trypanosomiasis infection using PCR techniques. Those that tested positive for T. brucei parasite were further tested using SRA LAMP technique to check for T. brucei rhodesiense, the human infective subspecies of parasite. RESULTS: Our study found a high incidence of Trypanosoma brucei infections across species. Of animals tested, 47 % of cattle, 91.7 % of sheep, and 60.8 % of goats were infected. Most of the infections were of the T. brucei species. We also identified sheep and goats as carriers of the T. brucei rhodesiense subspecies, which causes acute human trypanosomiasis. CONCLUSIONS: Together, these results point toward the need for stricter control strategies in the area to prevent disease outbreak.