Preliminary efficacy trial of Cymelarsan in dogs and mice artificially infected with Trypanosoma brucei isolated from dogs in Nigeria

Abstract

Efficacy of Mel Cy (Cymelarsan, Rhône Mérieux, France) against Trypanosoma brucei isolated from dogs was studied in experimentally infected mice and dogs. The mice were infected with parasites collected from five dogs and treated once intraperitoneally with Mel Cy at dose rates of 2.5 and 5.0 mg/kg seven and 14 days after infection, to give an indication on parasite sensitivity. Relapse of the parasitemia occurred in all groups of mice treated 14 days after infection, while almost all the mice treated seven days after infection remained parasitologically negative during the 63-day observation period. Five dogs were infected with a stock of the parasite then treated on the following postinfection days: day 7 (one dog), day 14 (two dogs), and day 21 (two dogs), at a dose of 2.5 mg/kg subcutaneously and on two consecutive days. Following the Mel Cy treatment, improvements in the clinical condition as well as weight gains were recorded in the dogs. A relapse of the infection occurred in only one of the two dogs treated 14 days after infection. Neither the dog treated at day 7 nor those treated at day 21 postinfection relapsed. It thus appears that, at the dose regimen used in this study, Mel Cy might be effective in the treatment of trypanosomosis due to T. brucei in dogs.