Rebecca Hardman, Gabriela Parra-Olea, Mirna Grisel Garcia-Castillo, Omar Becerra Soria, M. Delia Basanta, E. Davis Carter, Matthew Gray, Patrick Cusaac, Debra Miller
Chytrid Fungus (Batrachochytrium dendrobatidis or Bd) is a globally important pathogen implicated in several amphibian declines over the past few decades. However, it remains unclear how Bd has impacted salamander populations. Zoos and researchers have reported difficulty in transferring several salamander species from the wild into captivity, and Bd-chytridiomycosis is implicated in a majority of these observed deaths. Currently in Mexico, there are 90 lungless salamander (Family: Plethodontidae) species classified by IUCN as threatened or endangered. It is important to document these events to aid in future Bolitoglossan conservation plans that may require captive breeding colonies. Here we present a case report of mortality due to chytridiomycosis in the Mexican plethodontid salamander, Bolitoglossa platydactyla. Thirty-three apparently healthy animals were collected from sites in Veracruz, Mexico for transport to the United States for use in an ongoing disease study. All animals were collected and stored separately in individual containers. We changed gloves and used new materials for each individual to prevent any inter-individual contact and subsequent pathogen transfer. However, 13 individuals died within the two-week transfer and acclimatization period. The initial sign was acute lethargy, followed by complete tail drop and death within 12-24 hours. We performed histopathological analysis of four individuals from the mortality group. All individuals had marked erosion and ulceration affecting 75 % of the body with minimal remaining skin. Remaining remnants of skin contained numerous round organisms consistent Bd zoosporangia. Several ulcerated areas had large bacterial colonies covering the skin surface and invading the dermal layer. All animals were positive for Bd via qPCR assay. This report brings to light that B. platydactyla likely carry subclinical levels of Bd in the wild. It also follows that under some stressful conditions, these subclinically infected animals can develop clinical disease and succumb to chytridiomycosis.