title: In vivo experimental drug resistance study in Trypanosoma vivax isolates from tsetse infested and non-tsetse infested areas of Northwest Ethiopia.
abstract: Ethiopia, particularly in the Northwest region, is affected by both tsetse fly and non-tsetse fly transmitted trypanosomosis with a significant impact on livestock productivity. The control of trypanosomosis in Ethiopia relies on either curative or prophylactic treatment of animals with diminazene aceturate (DA) or isometamidium chloride (ISM), respectively. However, since these two trypanocides have been on the market for more than 40 years, this may have resulted in drug-resistance. Therefore, in vivo drug resistance tests on two Ethiopian isolates of Trypanosoma vivax were completed, one from an area where tsetse flies are present and one from an area where tsetse flies are not present. Twenty four cattle (Bos indicus) aged between 6 and 12 months, purchased from a trypanosome-free area (Debre Brehan: Northcentral Ethiopia) and confirmed to be trypanosome-negative, were randomly assigned into four groups of six animals, which were infected with T. vivax isolated from a tsetse-infested or non-tsetse infested area, and in each case treated with curative doses of DA or ISM. Each animal were inoculated intravenously 3×10(6) trypanosomes from donor animals. Parasitaemia became patent earlier in infections with non-tsetse T. vivax (∼7 days post-infection) than tsetse (∼14 days post-infection). Both groups were treated at the highest peak parasitaemia with DA or ISM and nine cattle, four with non-tsetse T. vivax (two ISM- and two DA-treated) and five with tsetse T. vivax (three ISM- and two DA-treated) showed relapses of parasitaemia. Moreover, treatment did not improve diagnostic host markers of trypanosome infections in these animals. In conclusion, in vivo drug tests indicated the presence of resistant parasites (>20% of treated animals in each group relapsed) against recommended doses of both available trypanocidal drugs.
authors: Addis Ababa University, CVMA, P.O. Box 34, Debre Zeit, Ethiopia. Electronic address: dagne2121@gmail.com.
authors: Shimelis
authors: S
authors: Dagnachew
authors: Addis Ababa University, CVMA, P.O. Box 34, Debre Zeit, Ethiopia.
authors: Getachew
authors: G
authors: Terefe
authors: Food and Agriculture Organization of the United Nations, FAO, Addis Ababa, Ethiopia.
authors: Getachew
authors: G
authors: Abebe
authors: University of Glasgow, CMVLS, G12 8TA Glasgow, United Kingdom.
authors: Dave
authors: D
authors: Barry
authors: University of Glasgow, CMVLS, G12 8TA Glasgow, United Kingdom.
authors: Richard
authors: R
authors: McCulloch
authors: Faculty of Bioscience Engineering, KU Leuven, B-3001 Heverlee, Belgium.
authors: Bruno
authors: B
authors: Goddeeris
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000469:parasitology; D003141:Communicable Diseases / Q000469:parasitology; D004133:Diminazene / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D004351:Drug Resistance; D005002:Ethiopia / Q000453:epidemiology; D007303:Insect Vectors; D008297:Male; D018512:Parasitemia / Q000188:drug therapy; D010617:Phenanthridines / Q000494:pharmacology / Q000627:therapeutic use*; D014344:Trypanocidal Agents / Q000494:pharmacology / Q000627:therapeutic use; D014348:Trypanosoma congolense / Q000302:isolation & purification; D016689:Trypanosoma vivax / Q000187:drug effects*; D014353:Trypanosomiasis, African / Q000188:drug therapy* / Q000469:parasitology / Q000635:transmission / Q000662:veterinary*; D014370:Tsetse Flies / Q000469:parasitology
chemical_list: D010617:Phenanthridines; D014344:Trypanocidal Agents; C000702:isometamidium chloride; C003915:diminazene aceturate; D004133:Diminazene
keywords: Cattle; Drug resistance; Northwest Ethiopia; Trypanosoma vivax