• Journal of Ecology and Environment
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• 제46권4호
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• pp.276-281
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• 2022

Ranaviruses are a primary cause of amphibian extinctions. More consistent ranavirus-infection reports and genetic characterizations of identified viruses are urgently needed, particularly from Asian countries. The objectives of this study were to obtain the partial major capsid protein (MCP) gene sequences (506 bp) of the ranavirus responsible for infecting frogs in South Korea, as our previous research had confirmed using qPCR, and to evaluate their genetic relationships with other previously reported ranavirus sequences. Three different ranavirus MCP sequences were obtained from Pelophylax nigromaculatus and Lithobates catesbeianus. All six different types of MCP sequence from the ranavirus identified in South Korea to date belonged to the Frog virus 3 (FV3)-like virus group in the genus Ranavirus. To better understand the origin and spread of ranaviruses in South Korea, further infection reports and full genome analyses of the identified ranaviruses are needed.

• Journal of Ecology and Environment
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• 제45권1호
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• pp.10-16
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• 2021

Background: Ranavirus is an emerging infectious disease which has been linked to mass mortality events in various amphibian species. In this study, we document the first mass mortality event of an adult population of Dybowski's brown frogs (Rana dybowskii), in 2017, within a mountain valley in South Korea. Results: We confirmed the presence of ranavirus from all collected frogs (n = 22) via PCR and obtained the 500 bp major capsid protein (MCP) sequence from 13 individuals. The identified MCP sequence highly resembled Frog virus 3 (FV3) and was the same haplotype of a previously identified viral sequence collected from Huanren brown frog (R. huanrenensis) tadpoles in South Korea. Human habitat alteration, by recent erosion control works, may be partially responsible for this mass mortality event. Conclusion: We document the first mass mortality event in a wild Korean population of R. dybowskii. We also suggest, to determine if ranavirus infection is a threat to amphibians, government officials and researchers should develop continuous, country-wide, ranavirus monitoring programs of Korean amphibian populations.

• Journal of Ecology and Environment
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• 제47권2호
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• pp.35-41
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• 2023

Background: Several species of amphibians in agricultural areas are often infected with ranaviruses; however, the biological or ecological factors that cause this infection are not well understood. In this study, we investigated whether local tadpole density, Gosner developmental stage, and weather conditions affected ranavirus infection in Dryophytes japonicus tadpoles in rice paddies over three months. Results: During the study, eight samplings were undertaken between June 6 and August 21, 2022. No die-off of tadpoles occurred, but 20 of 110 tadpoles (18.8%) were found to be infected with ranavirus. The tadpole density at the sampling site and Gosner stage of the sampled tadpoles were not related to the daily ranavirus infection rate. The mean daily highest temperature during the two weeks prior to the sampling date and the mean daily lowest and highest temperatures during the week prior to the sampling date were negatively related to the daily infection rate. Conclusions: Our results suggest that low and extreme temperatures caused by flooding and draining of paddy fields or climate change in summer could be a significant risk factor for ranavirus infection in summer-breeding frogs in agricultural areas.

• 환경생물
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• 제27권1호
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• pp.110-113
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• 2009

In recent years, there has been a rapid global decline in amphibian populations, and infectious diseases have been associated with this decline. Diseased Gold-spotted pond frogs (Rana plancyi chosenica) were collected from a frog farm in Korea and identified using morphological and molecular analysis to identify the disease. The typical symptoms of ranaviral infection were observed in the tadpoles and adults frogs. The nucleotide sequence analysis revealed that the sequences showed the closest similarity with sequences to Frog virus 3, which belongs to the genus Ranavirus.

• 환경생물
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• 제27권1호
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• pp.73-81
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• 2009

멸종위기종 금개구리 (Rana chosenica)개체군의 존속 가능성을 알아보고 효과적인 보전 대책의 마련과 야생복귀 방법을 개발하기 위하여 충북 청원군에 서식하는 개체군을 대상으로 개체군생존분석을 실시하였다. 해당 금개구리의 개체군은 30년간 1,000회의 시뮬레이션을 통해 0.113의 낮은 성장률을 가지고 존속해 나갈 것이라 예측이 되었으나 절멸가능성 또한 81.1%로 매우 높아 환경적으로 민감한 특징을 가지고 있었다. 금개구리 개체군의 개체군 성장률과 절멸가능성은 변태율의 변화에 대해 가장 민감하게 반응하는 것으로 나타났는데, 이는 금개구리의 야외 개체군을 안정적으로 유지하기 위해서는 무엇보다도 금개구리 유생이 변태할 때까지의 생존율을 높이는 것이 결정적이라는 것을 의미한다. 항아리곰팡이병이나 개구리바이러스와 같은 질병이 발병할 경우 개체군의 절멸확률이 100%로 예측되었다. 절멸 개체군의 야생개체군 복원의 방법으로는 수컷의 비율을 83%, 투여개체들의 나이구조가 정상분포를 보이는 100마리의 개체군을 200마리를 수용할 수 있는 지역에 복귀를 시키고, 4년 후 2년 단위로 10년 후까지 10%씩 보충하는 방법이 가장 안정된 개체군을 복원, 유지하는 방법으로 나타났으며, 이 복원된 개체군의 경우 지속적으로 금개구리의 유생이 변태할 때까지의 생존율을 높일 수 있는 보호대책이 마련된다면 성장률 0.297, 절멸가능성 0.290을 갖는 안정된 개체군을 30년 후 138마리까지 유지할 수 있을 것으로 분석되었다. 이러한 결과들은 금개구리 개체군의 보전과 재도입을 위한 효과적인 전략수립의 근거로 활용될 수 있을 것이다.