RESEARCH ARTICLE Co-Infection by Chytrid Fungus and Ranaviruses in Wild and Harvested Frogs in the Tropical Andes

While global amphibian declines are associated with the spread of Batrachochytrium den-drobatidis (Bd), undetected concurrent co-infection by other pathogens may be little recog-nized threats to amphibians. Emerging viruses in the genus Ranavirus (Rv) also cause die-offs of amphibians and other ectotherms, but the extent of their distribution globally, or how co-infections with Bd impact amphibians are poorly understood. We provide the first report of Bd and Rv co-infection in South America, and the first report of Rv infections in the amphibian biodiversity hotspot of the Peruvian Andes, where Bd is associated with extinc-tions. Using these data, we tested the hypothesis that Bd or Rv parasites facilitate co-infec-tion, as assessed by parasite abundance or infection intensity within individual adult frogs. Co-infection occurred in 30 % of stream-dwelling frogs; 65 % were infected by Bd and 40% by Rv. Among terrestrial, direct-developing Pristimantis frogs 40 % were infected by Bd, 35 % by Rv, and 20 % co-infected. In Telmatobius frogs harvested for the live-trade 49% were co-infected, 92 % were infected by Bd, and 53 % by Rv. Median Bd and Rv loads were similar in both wild (Bd = 101.2 Ze, Rv = 102.3 viral copies) and harvested frogs (Bd = 103.