Therapeutic activity of isometamidium chloride in Boran cattle against a tsetse-transmitted clone of Trypanosoma congolense with a low level of drug resistance.
Experiments were conducted with a clone of Trypanosoma congolense, IL 3580, which exhibited a low level of resistance to isometamidium chloride. Five cattle were treated intramuscularly with isometamidium chloride at a dose rate of 0.5 mg kg-1 body weight (BW) and challenged 28 days later with 5 Glossina morsitans centralis infected with T. congolense IL 3580. All 5 cattle and 15 untreated steers challenged on the same day became parasitaemic by day 15 post-infection. Thus, at a dose of 0.5 mg kg-1 BW, the prophylactic action of isometamidium chloride did not extend to 28 days following treatment. Subsequently, the 20 steers were divided into 4 groups of 5 animals each and treated with isometamidium chloride at one of the following dose rates; 0.5 or 1.0 mg kg-1 BW intramuscularly and 0.5 or 1.0 mg kg-1 BW intravenously (Groups A, B, C and D, respectively). Group A consisted of the 5 animals that had previously been treated with isometamidium chloride. Animals relapsed in all groups except those in Group B, treated intramuscularly with isometamidium chloride at a dose of 1.0 mg kg-1 BW. Four of the 5 animals in Group A, treated intramuscularly with isometamidium chloride at a dose of 0.5 mg kg-1 BW relapsed following a mean interval of 16 days post-treatment. Similarly, infections in all animals in Groups C and D, given intravenous injections of isometamidium chloride at a dose of 0.5 and 1.0 mg kg-1 BW, respectively, were not eliminated as a result of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Sutherland
I A
IA
University of Glasgow Veterinary School, Scotland, UK.
Codjia
V
V
Moloo
S K
SK
Holmes
P H
PH
Peregrine
A S
AS
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D004351:Drug Resistance; D007262:Infusions, Intravenous / Q000662:veterinary; D007273:Injections, Intramuscular / Q000662:veterinary; D007303:Insect Vectors / Q000469:parasitology; D008297:Male; D010617:Phenanthridines / Q000008:administration & dosage / Q000627:therapeutic use*; D014348:Trypanosoma congolense / Q000187:drug effects* / Q000235:genetics; D014353:Trypanosomiasis, African / Q000517:prevention & control / Q000662:veterinary*; D014354:Trypanosomiasis, Bovine / Q000517:prevention & control*; D014370:Tsetse Flies / Q000469:parasitology
D010617:Phenanthridines; C000702:isometamidium chloride