In vitro studies on the action of menoctone and other compounds on Theileria parva and T. annulata.

Bovine lymphoblastoid cell cultures permanently infected with Theileria parva and T. annulata were used in an in vitro screen to test a wide range of compounds for chemotherapeutic activity against these parasites. Only two compounds, menoctone and methotrexate, showed significant activity, which has subsequently been confirmed by tests in infected cattle. Menoctone was about 100 times more active than methotrexate. Mixtures of menoctone and various other other compounds were tested, but showed no potentiation. The activity of menoctone was antagonized by cycloguanil and methotrexate. The in vitro test represents a rapid, cheap, and apparently reliable method of screening compounds for activity against Theileria.