我国家蟋蟀浓核和虹彩病毒的流行病学分析

Epidemiology of Acheta domesticus densovirus and cricket iridovirus in China

摘要:

蟋蟀浓核病毒(Acheta domesticus densovirus, AdDV)于1977年在瑞士首次被分离得到，在欧洲与美国曾多次引发疫情。蟋蟀虹彩病毒(cricket iridovirus, CrIV)于1996年在荷兰首次被发现，患病蟋蟀出现死亡率升高、繁殖力降低和寿命缩短的现象。家蟋蟀(Acheta domesticus)原产于西南亚，近几十年来作为爬宠食物引入我国。AdDV与CrIV是家蟋蟀常见的病原体，随着我国家蟋蟀繁育设施的不断完善与宠物市场规模的日益扩大，对家蟋蟀病原的研究愈发重要。目的 了解AdDV与CrIV在我国的传播与流行现状，为控制病毒性病原体给家蟋蟀养殖业带来的危害，以及研发出有效的防治策略奠定理论基础。方法 广泛收集国内不同地区人工养殖的家蟋蟀，进行病毒特异的PCR检测，经Sanger测序进一步确证患病蟋蟀的病毒病原体，同时对患病蟋蟀中肠、脂肪体等组织进行透射电镜(transmission electron microscopy, TEM)观察，确定病毒粒子的形态特征。结果 AdDV病毒粒子为二十面体，近似球形，无囊膜，直径约20 nm，且在宿主细胞核内形成致密的染色质区，呈现典型的浓核病毒特征；CrIV病毒粒子呈二十面体，无囊膜，直径120-140 nm，在细胞质内形成类似晶格状的排列，呈现典型的虹彩病毒特征。病毒特异基因PCR检测发现，我国不同地区的家蟋蟀均能检出AdDV病毒，而绝大多数地区的家蟋蟀能检出CrIV病毒(91%)。已检测家蟋蟀中同时携带AdDV和CrIV病毒粒子的比率高达91%。结论 本研究发现AdDV与CrIV已在我国蟋蟀养殖业中广泛流行。

关键词:家蟋蟀;蟋蟀浓核病毒;蟋蟀虹彩病毒;流行病学

Abstract:

Acheta domesticus densovirus (AdDV) was first isolated from infected crickets in Switzerland, 1977 and caused several outbreaks in Europe and the United States. Cricket iridovirus (CrIV), first identified in the Netherlands in 1996, caused a high mortality rate, reduced the fertility, and shortened the life span of infected crickets. The house cricket (Acheta domesticus), was originated from south west Asia and introduced into China as food for reptile pets in recent decades. AdDV and CrIV are common pathogenic viruses that infect house crickets. Unveiling the virus epidemics of house crickets becomes increasingly important with the development of the house cricket industry.Objective To understand the epidemic status of AdDV and CrIV in China, so as to lay a theoretical basis for controlling AdDV and CrIV infections in the house cricket industry and developing effective prevention and control measures.Methods Virus-specific PCR was performed to detect pathogens of the crickets reared in farms spanning different regions of China. The pathogens of the infected crickets were further proved by Sanger sequencing. Transmission electron microscopy was employed to observe the virions in different tissue samples (e.g., gut and fat body) of the infected crickets.Results AdDV virions were icosahedral-shaped particles, nearly spherical, without envelope, with a diameter around 20 nm. It formed dense chromatin regions in the nucleus of the host cell, showing typical features of densovirus. CrIV virions were nonenveloped icosahedral-shaped particles with a diameter of 120-140 nm. A large number of CrIV virions formed a lattice-like arrangement in the cytoplasm, which is a typical feature of iridovirus. The virus-specific PCR detected AdDV in crickets collected from all the on-line shops distributed in different regions of China. CrIV was also detected in crickets collected from most (91%) of the on-line shops. The majority (91%) of detected crickets were infected with both AdDV and CrIV.Conclusion For the first time AdDV and CrIV were found to have been widely spread in China.

Key words:Acheta domesticus;Acheta domesticus densovirus;cricket iridovirus;epidemiology