Bovine trypanosome species prevalence and farmers’ trypanosomiasis control methods in south-western Uganda

Abstract

A cross-sectional study was conducted in Mbarara district, south-western Uganda in May 2012 to determine the burden of African animal trypanosomosis (AAT) in the semi-intensive dairy production systems where pyrethroid acaricides are frequently used in the control of tick-borne diseases (TBDs). A total of 295 cattle blood samples were taken and analysed using a single pair of primers previously designed to amplify internal transcribed spacer (ITS1) of trypanosome ribosomal deoxyribonucleic acid (rDNA). A structured questionnaire was administered to 55 participating livestock farmers to generate data on acaricide and trypanocidal drug usage. The overall prevalence of trypanosome species was 2.4% (95% CI; 1.0% – 4.8%); Trypanosoma vivax was the most predominant species (2.0%; 95% CI; 0.7% – 4.4%). A single mixed infection of T. vivax and Trypanosoma brucei s.l. was detected. All the participating farmers used acaricides for tsetse and TBD control; 89.1% of the acaricides used were pyrethroids. About half of the farmers used trypanocidal drugs, mainly diminazene formulations (Berenil®). Low prevalence of trypanosomes in examined samples is most likely related to the frequent use of pyrethroid insecticides, trypanocides and restricted grazing (paddocking and tethering). These rigorous management practices are geared towards optimising production of exotic dairy breeds kept in this region that are highly susceptible to TBDs and AAT.

Tsetse fly distribution and occurrence of Trypanosoma species among cattle and goats around Queen Elizabeth National park, Uganda

“…T. vivax was the least prevalent of all the species. This is contrary to other studies that have reported T. vivax as the most predominant species in the endemic parts of Uganda (5,11,14,24). However, the results are consistent with studies in Zambia (2,32,33), Nigeria (25,34), Ghana (1) and some parts of Uganda (35) where T. congolense was reported to be the most prevalent species.…”

“…The higher prevalence of trypanosomes in this study could probably be explained by the close proximity of the study sites to the QENP savannah grasslands that hosts various wildlife species that are possible reservoirs of Trypanosoma spp. Wildlife has previously been reported to be important reservoir and maintenance hosts of Trypanosoma spp (5,8,31). In addition, the difference in prevalence observed in Uganda could be due to variations in different geo-ecological zones and time of year for sampling (5,14,24,30).…”

“…Wildlife has previously been reported to be important reservoir and maintenance hosts of Trypanosoma spp (5,8,31). In addition, the difference in prevalence observed in Uganda could be due to variations in different geo-ecological zones and time of year for sampling (5,14,24,30). The type of husbandry practices such as communal grazing, free range grazing and climatic variations across different geographical regions can in uence the survival of both the parasites and vectors.…”

“…Tsetse ies play a big role in the transmission and spread of AAT among the various domestic and wild animals. In Uganda, over 70% of land is estimated to be infested with tsetse ies with approximately 60% of livestock at risk of AAT (4,5).…”

“…In humans, the disease is known as sleeping sickness or Human African Trypanosomiasis (HAT) while in animals it is called Nagana or AAT (6)(7)(8)(9). A range of wildlife serve as reservoirs of infection in domestic animals and humans (5). Trypanosomes, the causative agents of the disease are vectored by tsetse y of the genus Glossina and their distribution coincides with that of their vector (3,7,8).…”