Seasonal activity of ticks on small ruminants in Tamil Nadu State, India.

The seasonal activity of ticks on sheep and goat populations was examined from December 2000 to November 2001 in the state of Tamil Nadu, India. This longitudinal study spread over four seasons and seven agroclimatic zones took into consideration the spectrum of species involved, the levels of infestations, the seasonal epidemiology of ticks and the associated management practices. The most common species of tick spread throughout the state was Haemaphysalis bispinosa followed by Rhipicephalus haemaphysaloides, Hyalomma marginatum isaaci and Hyalomma anatolicum anatolicum with mixed infestations being the rule. Although the infestations were found throughout the year, they were greater during the rainy season and rainfall seemed to be the most important climatic factor affecting seasonal variation. In general, most of the small-ruminant populations carried moderate tick burdens with mixed infestations and this varied with the management practices.