TICKS AND TICK-BORNE BOVINE PIROPLASMOSIS IN THE SOUTHMOUNTAIN PASTURE OF HUNAN PROVINCE, CHINA

Ticks and tick-borne bovine piroplasmosis is one of the most serious d iseases affecting cattle bred in the Southmountain pasture of Hunan pr ovince. An investigation carried out from 1992 to 1995 showed that The ileria sergenti was found in the blood of disease-stricken cows. Ticks were collected from cattle. The species concerned (three genera and f our species of ticks: Haemaphysalis vietnamensis, Haemaphysalis longic ornis, Ixodes sinensis and Boophilus microplus) were identified by mic roscopy and their numbers recorded every month. Because H. longicornis is a three-host tick, with the larvae, nymphs and adults all infestin g cows and seasonal fluctuations in nymphs and adults correlating with theileriosis outbreaks, this tick species was a potential vector of T . sergenti. Epidemiological studies indicated that this disease usuall y occurred in summer or autumn. The disease attacked calves from May t o August reaching a peak in June or July (as happened from 1992-1994). In cattle, the disease occurred from June to September with a peak in September. The following pathological lesions were observed: haemorrh ages were seen in the subcutaneous tissues and serosa, in the intestin al mucosa and the mesenteric lymph nodes. The surface of the abomasum looked like a piece of red cloth. The liver was enlarged, its edge blu nt and curled over. The gall bladder was filled with tawny coloured bi le. The spleen was enlarged and dark brown. The heart was enlarged wit h numerous haemorrhagic foci in the auricle. The blood clotted incompl etely. Sick cattle were treated with Berenil and imidocarb and the dea th rate was reduced from 26% to 5.9%.