The fungal pathogen Batrachochytrium salamandrivorans is not detected in wild and captive amphibians from Mexico

Abstract

The recent emergence of the pathogen Batrachochytrium salamandrivorans (Bsal) is associated with rapid population declines of salamanders in Europe and its arrival to new areas could cause dramatic negative effects on other amphibian populations and species. Amphibian species, present in areas with high amphibian diversity such as Mexico, could be highly threatened due to the arrival of Bsal, particularly salamander species which are more vulnerable to chytridiomycosis caused by this pathogen. Thus, immediate surveillance is needed as a strategy to efficiently contend with this emerging infectious disease. In this study, we analyzed 490 wild and captive amphibians from 48 species across 76 sites in the North, Central, and South of Mexico to evaluate the presence of Bsal. Amphibians were sampled in sites with variable degrees of amphibian richness and suitability for Bsal according to previous studies. From the 76 sampling sites, 10 of them were located in areas with high amphibian richness and potential moderate to high Bsal habitat suitability. We did not detect Bsal in any of the samples, and no signs of the disease were observed in any individual at the time of sampling. Our results suggest that Bsal has not yet arrived at the sampled sites or could be at low prevalence within populations with low occurrence probability. This is the first study that evaluates the presence of Bsal in different regions and amphibian species in Mexico, which is the second most diverse country in salamander species in the world. We highlight the risk and the importance of continuing surveillance of Bsal in Mexico and discuss control strategies to avoid the introduction and spread of Bsal in the country.

Keywords: Amphibians; B. salamandrivorans; Chytridiomycosis; Disease ecology.

Figure 1. Sampled localities in Mexico analyzed for Batrachochytrium salamandrivorans (Bsal) detection.

(A) Map of amphibian richness in Mexico constructed using amphibian distribution maps of the IUCN (2022). (B) Map of Bsal habitat suitability obtained from García-Rodríguez et al. (2022) and categorized following Basanta, Rebollar & Parra-Olea (2019). Circles represent sampled sites for wild amphibians, and the white square represents the sample site for captive amphibians.