Effect of Streptomycin on Avian Malaria

Abstract

Streptomycin, an antibiotic produced by the soil actinomycete Streptomyces griseus, was first described by Schatz, Bugie, and Waks-man. 1 Unlike penicillin, streptomycin has been shown to have a high order of activity against certain gram negative infections both in vitro and in vivo.^2,3,4 Streptomycin has also been found to be active against the acid fast organism Mycobacterium tuberculosis both in vitro 5 and in the experimental animal. 6 In this communication we are reporting the results of studies on the activity of this antibiotic against avian malaria.

Trophozoite induced Plasmodium gallinaceum infections were established in 50 g Single Comb White Leghorn chicks by an intravenous inoculum of 200,000,000 parasitized erythrocytes per kilogram. The tests for suppressive activity against both trophozoite induced P. cathemerium and P. lophurae malaria were performed on 50 g Pekin ducklings inoculated intravenously with 500,000,000 parasitized erythrocytes per kilogram. The sporozoite induced P. gallinaceum infections used for the prophylactic tests were established in 50 g Single Comb White Leghorn chicks by the intravenous inoculation of 0.2 cc per bird of a suspension of sporozoites prepared by grinding 100 infected mosquitoes in 20 cc of chicken plasma.

The streptomycin used in these experiments was supplied by Merck & Co., Inc. and came from batch 162 which had a potency of 440 units per mg. 2 In all cases the streptomycin was administered as an aqueous solution intramuscularly every 3 hours. Birds inoculated with the trophozoites of P. cathemerium, P. gallinaceum and P. lophurae were treated for 5 days while the birds inoculated with the sporozoites of P. gallinaceum were treated for 3 days. Treatment was invariably begun within an hour following the inoculation. In the experiments with each infection, groups of 5 birds were given 400,000, 200,000, 100,000, 50,000 and 25,000 units respectively per kilogram per day.