Evaluating the impact of targeting livestock for the prevention of human and animal trypanosomiasis,at village level,in districts newly affected with T.b.rhodesiense in Uganda

Background:Uganda has suffered from a series of epidemics of Human African Trypanosomiasis(HAT),a tsetse transmitted disease,also known as sleeping sickness.The area affected by acute Trypanosoma brucei rhodesiense HAT(rHAT)has been expanding,driven by importation of infected cattle into regions previously free of the disease.These regions are also affected by African Animal Trypanosomiasis(AAT)demanding a strategy for integrated disease control.Methods:In 2008,the Public Private Partnership,Stamp Out Sleeping Sickness(SOS)administered a single dose of trypanocide to 31486 head of cattle in 29 parishes in Dokolo and Kaberamaido districts.This study examines the impact of this intervention on the prevalence of rHAT and AAT trypanosomes in cattle from villages that had(HAT^(+ve))or had not(HAT^(-ve))experienced a recent case of rHAT.Cattle herds from 20 villages were sampled and screened by PCR,pre-intervention and 6-months post-intervention,for the presence or absence of:Trypanosoma brucei s.l.;human infective T.b.rhodesiense;Trypanosoma vivax;and Trypanosoma congolense savannah.Results:Post-intervention,there was a significant decrease in the prevalence of T.brucei s.l.and the human infective sub-species T.b.rhodesiense in village cattle across all 20 villages.The prevalence of T.b.rhodesiense was reduced from 2.4%to 0.74%(P<0.0001),with the intervention showing greater impact in HAT^(-ve) villages.The number of villages containing cattle harbouring human infective parasites decreased from 15/20 to 8/20,with T.b.rhodesiense infection mainly persisting within cattle in HAT^(+ve) villages(six/eight).The proportion of T.brucei s.l.infections identified as human infective T.b.rhodesiense decreased after the intervention from 8.3%(95%CI=11.1-5.9%)to 4.1%(95%CI=6.8-2.3%).Villages that had experienced a recent human case(HAT^(+ve) villages)showed a significantly higher prevalence for AAT both pre-and post-intervention.For AAT the prevalence of T.vivax was significantly reduced from 5.9%to 0.05%post-intervention while the prevalence of T.congolense increased from 8.0%to 12.2%.Conclusions:The intervention resulted in a significant decrease in the prevalence of T.brucei s.l.,human infective T.b.rhodesiense and T.vivax infection in village cattle herds.The proportion of T.brucei s.l.that were human infective,decreased from 1:12 T.brucei s.l.infections before the intervention to 1:33 post-intervention.It is clearly more difficult to eliminate T.b.rhodesiense from cattle in villages that have experienced a human case.Evidence of elevated levels of AAT in livestock within village herds is a useful indicator of risk for rHAT in Uganda.Integrated veterinary and medical surveillance is key to successful control of zoonotic rHAT.

The diurnal activity, movement and trypanosome infection rates of Glossina fuscipes fuscipes （Diptera： Glossinidae） in Buvuma Island, Lake Victoria, Uganda

The diurnal activity patterns, trypanosome infection rates and movement of Glossinafuscipesfuscipes （Diptera： Glossinidae） were investigated in Buvuma Island, Lake Victoria, Uganda. Hourly trapping of tsetse flies was undertaken to determine their activity rhythm while a capture-mark-release-recapture method was conducted to assess the movement and dispersal of tsetse flies between lakeshore, hinterland and further inland sites along a transected area. Dissection of tsetse flies was also undertaken to determine the trypanosome infection rates in salivary glands, proboscis and mid-gut. Results indicated a bimodal diurnal activity profile for G. f fuscipes on the Island, both on the lakeshore and in the hinterland. Movement and dispersal of G. f fuscipes tsetse flies occurred between lakeshore, hinterland and further inland sites with a greater tendency of flies to move to the lakeshore. Trypanosome infection rates of 4.32% for Trypasoma vivax and 1.15% for 7. congolense were found in G. f. fuscipes.