Beisnoitia besnoiti : chemotherapeutic trials in vivo and in vitro

Abstract

Therapeutic potency of sulfonamides, pyrimethamine, trimethoprim,
halofuginone lactate, oxytetracycline, diminazene aceturate and pentamidine was examined in vivo during fatal experimental Besnoitia besnoiti infection in gerbils (Meriones tristami shawii). Complete animal protection was achieved with a single dose of long-acting oxytetracycline given intramuscularly at 200 mg/kg, while 50 p. 100 survival was observed after a 20 mg/kg dose. Treatment with a watersoluble formulation of oxytetracycline at 25 mg/kg for 9 successive days resulted in up to 76 p. 100 survival. Tbe other drugs were not effective against besnoitiosis in gerbils. In the in vitro experiments, oxytetracycline was completely inactive on B. besnoiti. Percentage of parasitized cells was markedly reduced to 0.5 p. 100 in cultures treated with the drug alone at 96 hours of incubation compared to 54 p. 100 in control non treated cells. Binding or mixing of halofuginone with antibodies reduced the drug activity. However the observed inhibition of endozoites multiplication cannot be attributed to a specific anti-Besnoitia activity, since a similar effect was obtained with immunoglobulins from Besnoitia-infected or healthy care.