Evaluation of anti-coccidial drugs' inhibition of Neospora caninum development in cell cultures.

Eight anti-coccidial drugs were examined for their efficacies in preventing development of Neospora caninum in bovine monocyte cell cultures. Lasalocid sodium (0.05 microgram/ml), monensin sodium (0.05 microgram/ml), piritrexim (0.01 microgram/ml), pyrimethamine (0.05 microgram/ml), and trimethoprim (5.0 micrograms/ml) were effective in preventing development of intracellular N. caninum tachyzoites (P less than 0.05). No differences (P greater than 0.05) in mean numbers of infected cells compared to controls were observed in cultures treated with amprolium hydrochloride (10.0 micrograms/ml), sulfadiazine (200.0 micrograms/ml), and sulfamethoxazole (200.0 micrograms/ml).