Abstract
ABSTRACTGlobally, ranavirus is often responsible for the mass mortality of a variety of captive and wild amphibians. In Asia, several mass mortality cases of captive amphibians by ranavirus are known, but one mass mortality case in the wild has been reported in a non-endemic larval bullfrog population in Japan. In order to verify factors involved in mass mortality of Rana huanrenensis tadpoles (> 200 tadpoles) in a mountain stream in South Korea, we investigated possible infections by ranavirus, chytrid fungus, and lethal bacteria by conducting PCR assays of pathogens with specific primers. We found that all R. huanrenensis tadpoles collected (two alive and ten carcasses) showed positive PCR results for two different ranavirus primer sets targeting partial genes of a major capsid protein (MCP). The identified MCP sequence was more closely related to Rana catesbeiana virus JP MCP, isolated from invasive bullfrog tadpoles in Japan. We could not detect any lethal bacteria or chytrid fungus in the specimens. Our finding is the first report in Asia that ranavirus is involved in the mass mortality of endemic wild amphibians.
Highlights
In recent decades, mass mortality events of amphibians have been increasing and emerging infectious diseases are recognized as one of the important factors (Fey et al 2015)
In Asia, mortality of captive or cultured amphibians by ranavirus are known from China, Japan, Thailand, and South Korea in Japanese clouded salamanders (Hynobius nebulosus, Une et al 2009a), Chinese giant salamanders (Andrias davidanus, Geng et al 2011), pig frogs (Rana grylio, Zhang et al 1996), tiger frogs (R. tigrina, Kanchanakhan 1998; Weng et al 2002), gold-spotted pond frogs (R. plancyi chosenica, Kim et al 2009), and imported captive frogs (Dendrobates and Phyllobates spp., Une et al 2014)
For the custom BLAST, we included 16 ranavirus major capsid protein (MCP) sequences retrieved from GenBank, which included those of the ranavirus previously known and often detected from amphibians, reptiles, and representative fishes (He et al 2002; Marsh et al 2002; Jancovich et al 2003; Holopainen et al 2009; Huang et al 2009; Une et al 2009b; Ariel et al 2010; Jancovich et al 2010; Geng et al 2011; Kim et al 2011; Lei et al 2012)
Summary
Mass mortality events of amphibians have been increasing and emerging infectious diseases are recognized as one of the important factors (Fey et al 2015). In order to detect bacterial infection we incubated samples of skin, digestive canal, and other internal tissues from six tadpoles (two alive and four dead) that were collected on June 18, 2015.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
