Claytor Sieara C, Subramaniam Kuttichantran, Landrau-Giovannetti Nelmarie, Chinchar V Gregory, Gray Matthew J, Miller Debra L, Mavian Carla, Salemi Marco, Wisely Samantha, Waltzek Thomas B
Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL, USA.
Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, USA.
Virology. 2017 Nov;511:330-343. doi: 10.1016/j.virol.2017.07.028. Epub 2017 Aug 10.
Ranaviruses are emerging pathogens of fish, amphibians, and reptiles that threaten aquatic animal industries and wildlife worldwide. Our objective was to genetically characterize ranaviruses isolated during separate bullfrog Lithobates catesbeianus die-offs that occurred eight years apart on the same North American farm. The earlier outbreak was due to a highly pathogenic strain of common midwife toad virus (CMTV) previously known only from Europe and China. The later outbreak was due to a chimeric ranavirus that displayed a novel genome arrangement and a DNA backbone typical for Frog virus 3 (FV3) strains except for interspersed fragments acquired through recombination with the CMTV isolated earlier. Both bullfrog ranaviruses are more pathogenic than wild-type FV3 suggesting recombination may have resulted in the increased pathogenicity observed in the ranavirus isolated in the later outbreak. Our study underscores the role international trade in farmed bullfrogs may have played in the global dissemination of highly pathogenic ranaviruses.
蛙病毒是鱼类、两栖动物和爬行动物的新兴病原体，威胁着全球的水产养殖业和野生动物。我们的目标是对在同一个北美养殖场相隔八年发生的两次牛蛙死亡事件中分离出的蛙病毒进行基因特征分析。较早的一次疫情是由一种高致病性的普通产婆蟾病毒（CMTV）毒株引起的，该毒株此前仅在欧洲和中国发现过。较晚的一次疫情是由一种嵌合蛙病毒引起的，该病毒显示出一种新的基因组排列，以及除了通过与早期分离出的CMTV重组获得的散布片段外，具有蛙病毒3（FV3）毒株典型的DNA骨架。两种牛蛙蛙病毒都比野生型FV3更具致病性，这表明重组可能导致了在较晚疫情中分离出的蛙病毒中观察到的致病性增加。我们的研究强调了养殖牛蛙的国际贸易在高致病性蛙病毒全球传播中可能发挥的作用。
