Abstract
The recent paper by Hardcastle and Foster 1 reporting encouraging results with the use of borax in the control of cecal coccidiosis in poultry suggested the possibility that boron derivatives might be effective as chemother-apeutic agents in certain types of avian malaria.
Trophozoite-indueed Plasmodium gallin-aceum infections were established in S.C. White Leghorn chicks weighing 50 g by intravenous inoculation of 200,000,000 parasitized erythrocytes per kg; trophozoite-indueed P. cathemerium infections were induced in Peking ducklings weighing 50 g by the intravenous injection of 500,000,000 parasitized erythrocytes per kg. Sporozoite-induced P. gallinaceum infections were used in prophylactic tests and were established in chicks of 50 g weight by injecting intravenously 0.2 cc per chick of a suspension of sporozoites prepared by grinding 100 infected mosquitoes in 20 cc of chicken plasma.
The boric acid was administered by incorporating it in the diet, a commercial chick starting mash, in the amounts shown in Table I. The birds were given the drug-containing diet immediately after inoculation and were permitted to feed ad libitum throughout the period of the test. The trophozoite-in-fected birds were continued on the drug-diet for 5 days. The chicks receiving the sporo-zoite inoculation were fed the drug-diet for 3 days and were then transferred to the regular untreated stock diet for an additional 6 days.
At the end of the respective test period, thin blood smears were prepared, stained with Giemsa, and the effect of the therapy was judged by determining the number of parasitized cells among 10,000 erythrocytes. In each experiment a group of untreated birds and at least one group treated with a drug of known antimalarial activity served as controls.
The results of the experiments on trophozoite- and sporozoite-induced avian malaria are given in Table I. Whereas quinine, atabrine and sulfadiazine can be used interchangeably as suppressives for the trophozoite infections, only sulfadiazine has prophylactic activity against P. gallinaceum
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