In vitro titration of Theileria parva tick derived stabilates

Immunization agairist the protozoan Theileria parva by infection and treatment has proved to be very efficient for the Control Of East Coast fever, an acute and often-fatal lymphoproliferative tick-borlic disease of cattle in Eastern, Central and Southern Africa. The immunizing dose of live T. Parva sporozites used in this method is usually determined by in vitro titration. An alternative in vivo method of quantitification of sporozoites ill whole tick-derived stabilites is proposed. The method consists of incubating serially diluted T. Parva stabilities with boville peripheral blood lymphocytes, the host cell that is infected naturally. Allowing the cultures to incubate undisturbed for the full cultivation period (10 days) reduced the variability amoung replicate titrations. fungal contaminations were avoided by centrifuging stabilates at 400 g prior to the incubation, which did not precipiate sporozoites significantly. Fungistics, Nysatin and Flucytosine did not appear to interfere with the in vitro development of 2 stabilates but their effect on fungal growth was limited. In vitro titration data were compared to in vivo infection data for 2. In vivo titration of T. parva sporozoites should allow more ethicl and efficient research on the preparation and storage of T. Parva tick-derived stabilates.