title: RANAVIRUS CAUSES MASS DIE-OFFS OF ALPINE AMPHIBIANS IN THE SOUTHWESTERN ALPS, FRANCE.
abstract: Pathogenic fungi and viruses cause mortality outbreaks in wild amphibians worldwide. In the summer of 2012, dead tadpoles and adults of the European common frog Rana temporaria were reported in alpine lakes in the southwestern Alps (Mercantour National Park, France). A preliminary investigation using molecular diagnostic techniques identified a Ranavirus as the potential pathogenic agent. Three mortality events were recorded in the park, and samples were collected. The amphibian chytrid fungus Batrachochytrium dendrobatidis was not detected in any of the dead adult and juvenile frogs sampled (n=16) whereas all specimens were positive for a Ranavirus. The genome sequence of this Ranavirus was identical to previously published sequences of the common midwife toad virus (CMTV), a Ranavirus that has been associated with amphibian mortalities throughout Europe. We cultured virus from the organs of the dead common frogs and infecting adult male common frogs collected in another alpine region where no frog mortality had been observed. The experimentally infected frogs suffered 100% mortality (n=10). The alpine die-off is the first CMTV outbreak associated with mass mortality in wild amphibians in France. We describe the lesions observed and summarize amphibian populations affected by Ranaviruses in Europe. In addition, we discuss the ecologic specificities of mountain amphibians that may contribute to increasing their risk of exposure to and transmission of Ranaviruses.
authors.affiliation: 1   Unité Mixte de Recherche, 5175 Centre d'Ecologie Fonctionnelle et Evolutive, Ecole Pratique des Hautes Etudes, Biogéographie et Ecologie des Vertébrés, 34293 Montpellier, France.
authors.forename: Claude
authors.initials: C
authors.lastname: Miaud
authors.affiliation: 2   LDA39, 59 rue Vieil Hôpital, 39802 Poligny, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Pozet
authors.affiliation: 3   Unité Mixte de Recherche, 5553 Université Savoie Mont Blanc, Laboratoire d'Ecologie Alpine, 73376 Le Bourget du Lac, France.
authors.forename: Nadine Curt Grand
authors.initials: NC
authors.lastname: Gaudin
authors.affiliation: 4   Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium.
authors.forename: An
authors.initials: A
authors.lastname: Martel
authors.affiliation: 4   Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, 9820 Merelbeke, Belgium.
authors.forename: Frank
authors.initials: F
authors.lastname: Pasmans
authors.affiliation: 5   Université Nantes Angers Le Mans, Oniris, Plateforme d'Analyse et de Service en Anatomie Pathologique, Nantes, F-44307, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Labrut
mesh_terms: D000663:Amphibians / Q000821:virology*; D000818:Animals; D000835:Animals, Wild; D004266:DNA Virus Infections / Q000453:epidemiology / Q000401:mortality / Q000662:veterinary* / Q000821:virology; D004196:Disease Outbreaks / Q000662:veterinary*; D005602:France / Q000453:epidemiology; D017995:Ranavirus; D013997:Time Factors
keywords: Altitude; Batrachochytrium dendrobatidis; Rana temporaria; amphibian disease; experimental infection; ranavirus