The effects of drugs on the formation of Theileria annulata merozoites in vitro.

The effects of colchicine, taxol, dinitrophenol, sodium azide, TLA-144, and obioactin on Theileria annulata schizonts were tested in vitro and studied by means of light and electron microscopy. Colchicine (0.001-5 microM) and taxol (1 microM) completely inhibited the mitosis of the host cell. This resulted in higher numbers of schizont nuclei after 96 h, since the division of the parasites was apparently not affected. Increasing numbers of schizont nuclei were also obtained after incubation of parasitized lymphocytes for 7 day at 41 degrees C with a daily medium exchange.