First occurrence of Ranavirus in Scandinavian peninsula

Abstract

Emerging infectious diseases (EIDs) pose a major threat to global amphibian populations, contributing to widespread mortality and species extinctions. Among EIDs, those caused by fungal infection pathogens Batrachochytrium dendrobatidis (Bd) and B. salamandrivorans (Bsal), and viral infections of the genus Ranavirus (Rv), represent the most significant threats to amphibian biodiversity. Here, we test for occurrence of Rv infection in three different locations in southeastern Sweden. Using a quantitative PCR (qPCR) assay, complemented by a secondary PCR-based validation method targeting the viral major capsid protein gene (MCP) and additional five partial sequences, we detected Rv infection in two of three locations and in five out of 43 individuals tested. This is the first confirmed record of Rv occurrence reported at such high latitudes in north Europe and the first one from Scandinavian peninsula, contributing important insights into infection prevalence in northern amphibian populations. These findings establish a basis for further research for the conservation of these vulnerable populations.