Theileria parva is a species of parasites, named in honour of Arnold Theiler, that causes East Coast fever (theileriosis) in cattle, a costly disease in Africa.

[1] Theiler found that East Coast fever was not the same as redwater, but caused by a different protozoan.

[2] When a tick ingests the piroplasms, the parasites undergo syngamy in the gut and can move to hemolymph.

[3] Theileria parva causes East Coast fever which results from infected lymphocytes.

[2] Blood smears can be performed to detect Theileria but can be hard to differentiate from other species.

For IFAT test, schizont or piroplasms are used from infected animals to identify transforming parasites.

[2] This method is economically friendly but is hard to differentiate between Theileria parva and other close species.

[2] Research is being done to create a vaccine with a mixture of many antigens from sporozoite and schizont stage to increase immunity.