**Endemic Infection of** *Batrachochytrium dendrobatidis* **in Costa Rica: Implications for Amphibian Conservation at Regional and Species Level**

**Héctor Zumbado-Ulate 1,\*, Kiersten N. Nelson 1, Adrián García-Rodríguez 2,3, Gerardo Chaves 2, Erick Arias 2,3, Federico Bolaños 2, Steven M. Whitfield 4 and Catherine L. Searle 1**


Received: 28 June 2019; Accepted: 7 August 2019; Published: 9 August 2019

**Abstract:** *Batrachochytrium dendrobatidis* (*Bd*) has been associated with the severe declines and extinctions of amphibians in Costa Rica that primarily occurred during the 1980s and 1990s. However, the current impact of *Bd* infection on amphibian species in Costa Rica is unknown. We aimed to update the list of amphibian species in Costa Rica and evaluate the prevalence and infection intensity of *Bd* infection across the country to aid in the development of effective conservation strategies for amphibians. We reviewed taxonomic lists and included new species descriptions and records for a total of 215 amphibian species in Costa Rica. We also sampled for *Bd* at nine localities from 2015–2018 and combined these data with additional *Bd* occurrence data from multiple studies conducted in amphibian communities across Costa Rica from 2005–2018. With this combined dataset, we found that *Bd* was common (overall infection rate of 23%) across regions and elevations, but infection intensity was below theoretical thresholds associated with mortality. *Bd* was also more prevalent in Caribbean lowlands and in terrestrial amphibians with an aquatic larval stage; meanwhile, infection load was the highest in direct-developing species (forest and stream-dwellers). Our findings can be used to prioritize regions and taxonomic groups for conservation strategies.

**Keywords:** amphibian; chytridiomycosis; conservation; disease; enzootics; epizootics; population declines
