Field evaluation of the prophylactic effect of an isometamidium sustained-release device against trypanosomiasis in cattle.
In order to compare the prophylactic effect provided by a poly(D,L-lactide) sustained-release device (SRD) containing isometamidium (ISMM) with that provided by the classical intramuscular injection of the drug, a field trial was carried out at the Madina Diassa Ranch in Mali. One- to 3-year-old N'Dama cattle were randomly divided into three groups. The first group (n = 42) was treated with ISMM at a dose of 1 mg/kg of body weight, the second group (n = 44) received the same dose of the drug via an SRD, which was subcutaneously implanted in the shoulder region, and the third group (n = 36) was kept as an untreated control group. All animals were treated with diminazene aceturate (7 mg/kg of body weight) 2 weeks before the start of the experiment and were tested monthly by the buffy coat technique for a period of 8 months. Glossina morsitans submorsitans was the most important tsetse species, with apparent densities (number of catches/trap/day) varying between 11.9 and 38.7 over the experimental period. Eight months after treatment the cumulative infection rates were 27.7, 58.5, and 77.4% in the group with the SRD implant, the group receiving the intramuscular injection, and the control group, respectively. Statistical analysis showed that the incidence of trypanosomiasis was significantly lower (P = 0.006) in the group which received ISMM via the SRD than in the one which was treated with ISMM intramuscularly.
Diarra
B
B
Laboratoire Central Vétérinaire, Bamako, Mali.
Diall
O
O
Geerts
S
S
Kageruka
P
P
Lemmouchi
Y
Y
Schacht
E
E
Eisler
M C
MC
Holmes
P
P
D000818:Animals; D002417:Cattle; D003692:Delayed-Action Preparations; D005260:Female; D007303:Insect Vectors; D008297:Male; D010617:Phenanthridines / Q000627:therapeutic use*; D014344:Trypanocidal Agents / Q000627:therapeutic use*; D014345:Trypanosoma / Q000187:drug effects*; D014354:Trypanosomiasis, Bovine / Q000517:prevention & control*; D014370:Tsetse Flies / Q000469:parasitology
D003692:Delayed-Action Preparations; D010617:Phenanthridines; D014344:Trypanocidal Agents; C000702:isometamidium chloride