中国对虾呼肠孤样病毒感染的电镜观察

呼肠孤病毒在自然界广泛存在于脊椎动物、无脊椎动物和植物中.水产动物呼肠孤病毒感染曾见于鱼、贝、蟹.近几年随着对对虾病毒病害研究的日益重视,在对虾中也发现呼肠孤病毒的感染.Tsing等[1]最早于1987年在法国南部养殖的日本对虾(P.japonicus)幼虾中发现呼肠孤病毒感染.Krol等[2]于1990年在试验感染的南美白对虾(P.vannamei)中发现呼肠孤样病毒与对虾杆状病毒混合感染.中国大陆养殖的中国对虾自1993年全面暴发流行病以来,许多学者进行了对虾流行病的病原学、流行病学及诊断和防治方法的研究,部分学者曾在中国对虾(P.chinensis)中观察到呼肠孤样病毒颗粒[3],但未报道较详细的电子显微镜观察资料.

Visualization of Reo-like Virus Infection in Cultivated Penaeus chinensis by Electron Microscopy

In 1996,a serious epizootic called white spot syndrome caused high mortality of cultivated Penaeus chinensis in Qingdao from June to August.Electron microscopy and reinfection test showed that Penaeus chinensis non occluded baculovirus (PcNOBV),the WSBV isolate from P.chinensis in mainland China,is the major causative agent of the epizootic.Meanwhile,reovirus like particles were observed in some of the diseased P.chinensis from the following sample tissues:gill,stomach,foregut and ovary.The reovirus like particles could sometimes be found infecting the same shrimp or the same tissue and even the same cell with PcNOBV.The viral particles were spherical with double shelled structure characteristic of reovirus without envelope and located in the cytoplasm of infected tissue cells.The diameter of the particle varies in different tissues ranging from 80 110nm.The size of inner core is 60nm.Based on its morphologic characteristics,the virus is assumed to be a reovirus and named Penaeus chinensis reo like virus(PcREO)temporally.It's not clear currently what roles does it play in the occurrence of the epizootic.However,the facts of systemic infection of the virus in P.chinensis and dual infection with PcNOBV strongly indicate that PcREO might contribute to the occurrence of the epizootic.Further research is required to determine its characteristics of pathogenicity,biology and molecular biology.