Five-fold increase in Trypanosoma congolense isolates resistant to diminazene aceturate over a seven-year period in Eastern Zambia.
Two groups of Trypanosoma congolense isolates collected from cattle in 1996 (n=39) and 2003 (n=38) in the Eastern Province of Zambia were analyzed by BclI-PCR-RFLP to assess the evolution of diminazene aceturate (DA) resistance over a period of seven years. The results show a significant increase of DA resistance in this relatively short period of time. In 1996, among the 39 isolates, 61.5% were found sensitive, 12.8% resistant and 25.7% had a mixed BclI-PCR-RFLP profile. In 2004, among the 38 isolates, 10.5% were found sensitive, 63.2% were resistant and 26.3% showed a mixed BclI-PCR-RFLP profile. In vivo tests in mice showed that isolates with a sensitive or mixed RFLP profile were sensitive to DA whereas isolates with a resistant RFLP profile were resistant. Since there are no indications that the drug pressure has increased between 1996 and 2003, it is suggested that genetic exchange of resistance genes might explain the increased frequency of resistance to DA.
Delespaux
Vincent
V
Animal Health Department, Institute of Tropical Medicine (Antwerp), Nationalestraat 155, B-2000 Antwerp, Belgium. vdelespaux@itg.be
Dinka
Hunduma
H
Masumu
Justin
J
Van den Bossche
Peter
P
Geerts
Stanny
S
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy / Q000469:parasitology*; D016054:DNA, Protozoan / Q000235:genetics; D004133:Diminazene / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance / Q000187:drug effects* / Q000235:genetics; D051379:Mice; D008815:Mice, Inbred Strains; D012150:Polymorphism, Restriction Fragment Length; D014344:Trypanocidal Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D014348:Trypanosoma congolense / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D014353:Trypanosomiasis, African / Q000188:drug therapy* / Q000469:parasitology / Q000662:veterinary; D015024:Zambia
D016054:DNA, Protozoan; D014344:Trypanocidal Agents; C003915:diminazene aceturate; D004133:Diminazene