A drug incubation infectivity test (DIIT) for assessing resistance in trypanosomes.
Blood stream forms of drug-resistant and sensitive Trypanosoma brucei brucei, Trypanosoma brucei evansi and Trypanosoma vivax were incubated in a liquid medium for 24 h at 37 degrees C in the presence of various concentrations of diminazene aceturate (Berenil) or isometamidium chloride (Samorin), and assayed for infectivity in mice. Whereas the infectivity to mice of all Samorin-sensitive trypanosomes was decreased after incubation with 1 ng Samorin ml-1, the Samorin-resistant stocks remained infective for mice. Two of the Samorin-resistant stocks remained infective after incubation with Samorin concentrations of up to 50 ng ml-1. The infectivity of Berenil-resistant trypanosome stocks were also retained after incubation with drug concentrations (0.5 or 1.0 micrograms ml-1) which otherwise inhibited the infectivity of Berenil-sensitive trypanosome stocks. In addition, differences in infectivity were observed when Berenil-resistant and sensitive trypanosome stocks were incubated in medium supplemented with serum from goats previously treated with Berenil. Thus, drug-resistant and sensitive trypanosomes can be clearly distinguished using the drug incubation infectivity test.
Kaminsky
R
R
International Laboratory for Research on Animal Diseases, Nairobi, Kenya.
Gumm
I D
ID
Zweygarth
E
E
Chuma
F
F
D000578:Amidines / Q000494:pharmacology*; D000818:Animals; D004133:Diminazene / Q000031:analogs & derivatives / Q000494:pharmacology*; D004351:Drug Resistance; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D010617:Phenanthridines / Q000494:pharmacology*; D014344:Trypanocidal Agents / Q000494:pharmacology*; D014345:Trypanosoma / Q000187:drug effects* / Q000502:physiology; D014346:Trypanosoma brucei brucei / Q000187:drug effects* / Q000502:physiology; D014352:Trypanosomiasis / Q000469:parasitology
D000578:Amidines; D010617:Phenanthridines; D014344:Trypanocidal Agents; C000702:isometamidium chloride; C003915:diminazene aceturate; D004133:Diminazene