关键词: 火鸡, 冠状病毒, 病毒分离, 初步鉴定

Abstract: An acutely infectious disease was encountered in turkey poults of 15-28 days old at a turkey farm in 2003. The affected birds presented with diarrhoea, the hyperaemia and hemorrhage of duodenum and rectum, cecum tumescence, intestines filled with yellow contents and 10% to 20% mortality. Livers, spleens and intestines obtained from died poults were homogenized and centrifuged. The supernatant was inoculated into 15-day-old specific pathogen free (SPF) embryonated chicken eggs to propagate the viruses. After 5 successive passages, the yolk and intestine of infected chicken embryos were harvested and homogenized 72 hours post-inoculation, for determining viral hemagglutination and purifying the viruses. The isolate had the ability to hemagglutinate erythrocytes from rabbit but not from chicken, and several spherical or oval viral particles with corona were observed by electron microscopy, which indicated the isolated viruses may be turkey coronaviruses. Furthermore, TCV S2 gene was amplified from the extracted total RNA of infected chicken embryos intestines by reverse transcriptionpolymerase chain reaction (RTPCR) with designed primers, and the products were identical with the expectation. In addition, 3 days after 1-day-old turkey poults were orally inoculated with 1 mL of the intestine homogenate of the infected chicken embryos, the infected birds showed the same clinical signs and pathological changes as natural infected cases described above. Above results showed that the isolated viruses were turkey coronaviruses. It is the first time that coronaviruses were isolated from turkey in China.

Key words: turkey, coronavirus, virus isolation, preliminary identification