Theileria infectivity of Hyalomma ticks in Haryana, India.

Theileria infection of Hyalomma ticks collected from three districts of Haryana was assessed in whole salivary glands by the methyl-green pyronin staining method. Of 1,662 ticks screened, 546 (32.8%) were found Theileria positive. Infection rate in 935 female ticks (36.9%) was more than that of 727 male ticks (27.6%). Density of Theileria infection (number of infected acini per infected tick) was also higher in female ticks. Theileria infection rate of ticks varied greatly in the three districts viz. only 12.0% in Rohtak, 25.8% in Hisar and 48.3% in Karnal. Per cent infection rate was high (63.7%) in ticks from indigenous cattle and low (18.6%) in those collected from buffaloes. However, the intensity of infection in infected ticks from cross-bred cattle was comparatively much higher. Frequency distribution of Theileria positive acini in infected ticks revealed a low density of infection per infected tick. This points to the largely stable endemic situation prevailing in Haryana. Only a single salivary acinus was found infected in 16.6% of the infected ticks, about 70% had up to 10 infected acini while only about 10% had over 25 infected acini per tick. The masses in acini presumed to be Theileria were confirmed by demonstrating parasitic masses on staining one of a pair of salivary glands and inoculating the suspension of the other half of the gland into two cross-bred cow calves which developed clinical signs and lesions typical of theileriosis.