A novel amphibian herpesvirus (candidate Batravirus ranidallo5) associated with disease in free-ranging Iberian painted frogs (Discoglossus galganoi) in Spain

Amphibians are undergoing a dramatic global decline. This massive biodiversity loss, which is critically impacting public and planetary health, has been attributed to multiple causes including infectious diseases. Of the known pathogens associated with obvious diseases in amphibians, herpesviruses have recently raised attention secondary to the discovery of two new species, both associated with skin diseases. Here, we provide the detection and characterization of a novel amphibian herpesvirus associated with a proliferative skin disease, closely resembling that previously described in association with Batravirus ranidallo3 (previously Ranid herpesvirus 3-RaHV3) and Bufonid herpesvirus 1 (BfHV1). The novel virus, tentatively named candidate Batravirus ranidallo5 is genetically related, but distinct from the previously described Batraviruses and it is the first amphibian herpesvirus described in Spain. The full-length genome obtained for this novel herpesvirus is approximately 220 kb and it contains the homologues of herpesvirus hallmark genes, which allows us to propose its unambiguous classification as a herpesvirus. Interestingly, a number of predicted ORFs showed to match closer to fish Alloherpesviruses homologues than Batraviruses. The discovery within a limited time span of three distinct herpesviruses, all associated with obvious skin diseases in Europe is alarming and may have significant implication for amphibian conservation.