Trop. Anita. Hlth Prod. (1990) 22, 63-65 TREATMENT OF BOVINE TROPICAL THEILE~OSIS WITH BUPARVAQUONE N. N. SHARMA and A. K. MISHRA Division of Parasitology, Indian Veterinary Research Institute, lzatnagar, UP, India SUMMARY The antitheilerial activity of buparvaquone in crossbred male calves, ex- perimentally infected with Theileria annulata (Izatnagar isolate) has been tested. Animals were treated intramuscularly at the dose rate of 2.5mg/kg I body weight. A single dose of the drug administered during the phase of ascending parasitaemia cured all the infected calves while all the untreated infected control calves died. INTRODUCTION The chemotherapeutic efficacy of a number of compounds has been tested against theileriosis caused by Theileria parva as well as 7". annulata. The recent addition to the list of such drugs is buparvaquone. This compound has been said not to be easily and quickly removed from the body system by the usual metabolic processes and therefore has sufficient opportunity to act upon the agent of the disease (McHardy, Wekesa, Hudson and Randall, 1985). The efficacy of buparvaquone has been tested in vitro as well as in vivo against 7". parva (Muguga), T. annulata (Ankara strain) (McHardy et al., 1985; McHardy, Wekesa and Morgan, 1987; Morgan and McHardy, 1986) and in vivo against T. annulata (Hissar isolate) (Dhar, Malhotra, Bhushan and Gautam, 1986, 1987). The present study was designed to demonstrate the potential of this drug against the Izatnagar isolate of T. annulata. MATERIALS AND METHODS Crossbred male susceptible calves, divided into two groups each with three animals, were used in the present study. The calves were procured when four to seven days old and housed in a tick and fly proof animal shed. At the age of four weeks they were sprayed with 0.15% diazinon ~ (0,0-diethyl-0-(2-isoprophyl-6- methyl-4-pyrimidinyl)-thiophosphate) twice a month to keep them free from ticks; the shed was also sprayed with 0.2% solution of diazinon with special attention to cracks and crevices. Prior to their experimental use, animals were dewormed by morantal tartrate. 2 The Izatnagar isolate of T. annulata, maintained by passage in bovines and ticks, was used in the present study. Ground-up tick supernate (GUTS) equivalent to 10 ticks, prepared from Hyalomma anatolicum anatolicum infected with T. annulata was used to induce infection in calves of both the groups. Clinical signs of disease, body temperature, parasitaemia (schizonts) in peripheral circulation, haemoglobin and packed cell volume (PCV) were the parameters taken into consideration. All the surviving calves were challenged on day 57 post-infection (PI) with a dose of parasites equivalent to that of the infecting dose. t Neocidol, Hindustan Ciba Geigy Ltd. 2 Banminth II, Pfizer, Ltd. 63