Batrachochytrium dendrobatidis not found in rainforest frogs along an altitudinal gradient of Papua New Guinea

Batrachochytrium dendrobatidis (Bd) is a fungal pathogen often responsible for amphibian declines worldwide. We report here survey on Bd in Papua New Guinea (PNG). The survey for Bd was conducted along a rainforest altitudinal gradient from Madang (50 m a.s.l.) to Mt. Wilhelm (3700 m a.s.l.). We swabbed 249 frogs of 63 native species at nine sites to quantify the number of Bd zoospore equivalents using real-time Syber Green Polymerase Chain Reaction (qPCR). We found no evidence for Bd. The lack of Bd may be due to 1) hot climate all year round inhibiting the spread of Bd in the entire lowland areas of PNG, 2) low number of non-native amphibian introductions to PNG such as Lithobates catesbeianus or Xenopus spp. or 3) the lack of invasive introductions by humans due to geographic isolation. While it is difficult to discern between these hypotheses, an effective quarantine should be devised to protect PNG from future disease outbreak. International assistance is needed in conservation education and research to assist the local scientists in monitoring and protecting these rich fauna from future Bd outbreaks.