Frequency of diminazene-resistant trypanosomes in populations of Trypanosoma congolense arising in infected animals following treatment with diminazene aceturate.

摘要: The frequency of trypanosomes resistant to diminazene aceturate at a dose 25 mg/kg body weight was investigated for populations Trypanosoma congolense IL 3274 which reappeared in infected mice after intraperitoneal treatment with the same dosage. At inoculum sizes 10(2), 10(3), 10(4), 10(5), and 10(6) per mouse, relapse were used initiate infections five groups 100 each by intravenous route. Immediately infection, 50 group treated intraperitoneally aforementioned dosage; other functioned as untreated controls. Thereafter, all animals monitored days presence trypanosomes. In group, detected control mice, indicating 100% infectivity sizes. contrast, 10(5) aceturate, 4, 11, 13, 28, 39 respectively. By logistic regression, good fit found between number identified parasitemic Maximum likelihood estimates proportions organisms 8.335 x 10(-4), 2.485 3.02 10(-5), 8.3 10(-6), 1.6 These finding indicate that majority susceptible drug dosage selecting population that, surprisingly, calculated proportion survived exposure varied inversely size. Further experiments indicated inverse relationship did not result from alterations pharmacokinetics different data therefore suggest parasite size are important factors estimating apparent diminazene-resistant T. occurring vivo.