Gray Matthew J, Miller Debra L, Hoverman Jason T
274 Ellington Plant Sciences Building, Center for Wildlife Health, Department of Forestry Wildlife and Fisheries, Institute of Agriculture, University of Tennessee, Knoxville, Tennessee 37996-4563, USA.
Dis Aquat Organ. 2009 Dec 3;87(3):243-66. doi: 10.3354/dao02138.
Mass mortality of amphibians has occurred globally since at least the early 1990s from viral pathogens that are members of the genus Ranavirus, family Iridoviridae. The pathogen infects multiple amphibian hosts, larval and adult cohorts, and may persist in herpetofaunal and osteichthyan reservoirs. Environmental persistence of ranavirus virions outside a host may be several weeks or longer in aquatic systems. Transmission occurs by indirect and direct routes, and includes exposure to contaminated water or soil, casual or direct contact with infected individuals, and ingestion of infected tissue during predation, cannibalism, or necrophagy. Some gross lesions include swelling of the limbs or body, erythema, swollen friable livers, and hemorrhage. Susceptible amphibians usually die from chronic cell death in multiple organs, which can occur within a few days following infection or may take several weeks. Amphibian species differ in their susceptibility to ranaviruses, which may be related to their co-evolutionary history with the pathogen. The occurrence of recent widespread amphibian population die-offs from ranaviruses may be an interaction of suppressed and naïve host immunity, anthropogenic stressors, and novel strain introduction. This review summarizes the ecological research on amphibian ranaviruses, discusses possible drivers of emergence and conservation strategies, and presents ideas for future research directions. We also discuss common pathological signs of ranaviral disease, methods for diagnostic evaluation, and ranavirus surveillance methods. In as much as ranaviral disease is listed as a notifiable disease by the World Organization for Animal Health and is a threat to amphibian survival, we recommend that biosecurity precautions are implemented by nations to reduce the likelihood of transporting ranavirus virions among populations. Biosecurity precautions include disinfecting footwear and equipment that comes in contact with surface water inhabited by amphibians and testing commercially shipped amphibians for the pathogen. We also encourage natural resource organizations to establish routine surveillance programs for ranaviruses in wild amphibian populations.
至少从20世纪90年代初以来，全球范围内两栖动物出现了大规模死亡，原因是感染了虹彩病毒科蛙病毒属的病毒病原体。该病原体可感染多种两栖动物宿主，包括幼虫和成年群体，并且可能在两栖类和硬骨鱼类宿主中长期存在。蛙病毒粒子在宿主外的环境中可持续数周或更长时间。传播途径包括间接和直接途径，包括接触受污染的水或土壤、与受感染个体偶然或直接接触，以及在捕食、同类相食或食腐过程中摄入受感染组织。一些明显的病变包括四肢或身体肿胀、红斑、肝脏肿大易碎和出血。易感两栖动物通常死于多个器官的慢性细胞死亡，感染后几天内或可能需要几周时间。两栖动物物种对蛙病毒的易感性不同，这可能与其与病原体的共同进化历史有关。近期蛙病毒导致两栖动物种群广泛死亡的现象，可能是宿主免疫抑制和幼稚、人为应激源以及新毒株引入相互作用的结果。本综述总结了关于两栖动物蛙病毒的生态学研究，讨论了可能的病毒出现驱动因素和保护策略，并提出了未来研究方向的思路。我们还讨论了蛙病毒疾病的常见病理症状诊断评估方法和蛙病毒监测方法。鉴于蛙病毒疾病被世界动物卫生组织列为须申报疾病，且对两栖动物生存构成威胁，我们建议各国实施生物安全预防措施，以降低蛙病毒粒子在种群间传播的可能性。生物安全预防措施包括对接触两栖动物栖息地表水的鞋类和设备进行消毒，以及对商业运输的两栖动物进行病原体检测。我们还鼓励自然资源组织为野生两栖动物种群建立蛙病毒常规监测计划。
