| Bovine babesiosis is caused by genus Babesia, which is transmitted by ticks and parasitizes in the erythrocytes of cattle. The disease is usually characterized by fever, hemolytic anemia, hemoglobinuria, and enen death in severe cases. It is widely distributed in China, and seriously affects cattle industry. Although works in different areas in babesiosis have been made, including causative agents, epidemiology, diagnosis and treatment etc., it is not enough to satisfy the needs of prophylaxis of bovine babesiosis. In this study, the classification of Chinese Babesia spp. infective to cattle were carried out by the classical methods and molecular biotechnology, and investigated the vector ticks of an unidentified Babesia sp. isolated from Xinjiang province by the experimental transmission, and observed the developmental forms of Babesia sp. in the engorged Hyalomma anatolicum anatolicum females; We developed the indirect hemoagglutination test for Babesia bigemina, and evaluated its effect in the sero-survey; We made slow-released injection of imidocarb, and estimated its efficacy on the treatment and prevention of Babesia bigemina infection by the laboratory work and the field tests. The major results were presented as following:1. Discovery of a bovine Babesia sp. transmitted by Hyalomma spp. in China and description of its morphology: A species of Babesia sp transmitted by Hyalomma anatolicum antolicum were identified and isolated in China. When larvae, nymphs and adults, which were developed from the engorged female of Hy. a. anatolicum collected from cattle in Xinjiang province, were infested on the Babesia-free calves, piroplasms of Babesia sp. were seen in the blood smears from cattle infested with nymphs (2/2),but not from the calves infested with larvae (0/1) and adult ticks (0/2). The Babesia sp. proved to be of low pathogenicity. The parasitemia lasted 3~4 days; the maximum parasitemia only reached 30 parasites per 1000 erythrocytes. In addition, the studies about the morphologyof intra-erythrocytic piroplasms and merozoites in tick haemolymph were carried out.2. Experimental transmission of an unnamed bovine Babesia by Hyalomma spp., Haemaphysalis longicornis and Boophilus microplus: Experiments were undertaken to determine the mode of transmission to cattle of an unnamed Babesia sp. by Hy. a. anatolicum, Hy. detritum, Hy. rufipes koch, Haemaphysalis longicornis and Boophilus microplus. The unnamed Babesia species designated Babesia U sp. was isolated by infesting cattle with nymphs from female Hy. a. anatolicum ticks collected from Xinjiang province. Adults of Hy. a. anatolicum, Hy. detritum and Hy. rufipes koch raised in laboratory were infected with Babesia U sp., isolated with nymphal ticks of Hy. a. anatolicum derived from females collected from field, by feeding on infected cattle. The experiments revealed that Hy. a. anatolicum was capable of transmitting Babesia U sp. transovarially in larval (2 of 4 calves), nymphal (6 of 6 calves) and adult (3 of 8 calves) stages, with prepatent periods of 16, 12, and 8 days respectively, and that this Babesia was also transovarially transmitted by both the nymphal and adult stages of Hy. detritum and Hy. rufipes. Attempts to transmit this Babesia U sp. transovarially with Hae. longicornis and Bo. microplus, and transtadially with Hyalomma spp., were carried out, and the results proved to be negative.3. At least two bovine piroplasms could be transmitted by Hyalomma anatolicum anatilicum ticks: one is T. annulata, the other is Babesia sp.: The cleaned unengorged adults H. a. anatolicum ticks cultivated in the laboratory were fed onto the calve artificially infected by an unidentified Babesia sp (designated as Babesia U sp.). When the female ticks engorged and dropped from the cattle, they were incubated at 28 and 80-90% relative humidity for oviposition. The subsequent larval and nymphal progeny were applied onto the calves infected with Theileria annulata in order to investigate whether Hy. a. anatolicum were infected by both Theileria annulata...
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