Fatal Theileria orientalis N2 genotype infection among Asian water buffaloes (Bubalus bubalis) in a commercial dairy farm in Kerala, India.

Fifteen dairy buffaloes of a farm in the state of Kerala, India developed fatal oriental theileriosis within 2 months of their procurement. Typical piroplasms of Theileria orientalis were observed in the erythrocytes of all affected animals by Giemsa-Leishman staining of blood smears. Case fatality rate was 87·5% (seven out of eight) in the clinically progressed cases.