SEASONAL DISTRIBUTION OF THEILERIA IN HYALOMMA-ANATOLICUM-ANATOLICUM TICKS OF AN ENDEMIC AREA OF HARYANA, INDIA

The effect of season on the capacity of Hyalomma anatolicum anatolicum ticks to transmit Theileria was studied by detecting Theileria sporob lasts in the salivary glands of 647 adult ticks moulted in winter (Nov ember 1990 to March 1991) and 677 adult ticks moulted in the summer-ra iny season (June to August 1991). The intensity (number of infected ac ini per infected tick) and abundance (number of infected acini per tic k examined) of Theileria sporoblasts were significantly (P < 0.05) hig her in winter moulted ticks (10.75 and 2.23 respectively) than the sum mer-rainy season moulted ticks (7.31 and 1.77 respectively). The preva lence of infected moulted ticks was not significantly higher in the su mmer-rainy season (24.22%) than in the winter (20.71%). A higher perce ntage of winter moulted ticks had high numbers of infected acini (grea ter-than-or-equal-to11/infected tick) than the summer-rainy season mou lted ticks, while the trend was reversed for low numbers of infected a cini (5/infected tick), being 47.76% for winter and 73.78% for the sum mer-rainy season. It was concluded that the winter of Haryana is more favourable to the developing theilerial stages in the ticks than the s ummer-rainy season.