From Field to Lab: Giant Toad (Rhinella horribilis) as an Emerging Model for the Study of Amphibian Blood Parasites.

Amphibians are experiencing significant declines due to habitat destruction, climate change, and the emergence of infectious diseases, such as chytridiomycosis. Despite their historical use as research models, standardized amphibian models are currently scarce. The Neotropics, particularly Colombia, host a remarkable diversity of amphibians, with approximately 876 species recorded. While hemoparasites are frequently reported in these species, their life cycles remain poorly characterized due to chronic infections and reliance on invertebrate vectors. This study identifies Rhinella horribilis (Wiegmann, 1833) as a promising animal model for pathogen research. These toads are widespread in the Neotropics; in fact, other members of this genus, such as Rhinella marina (Linnaeus, 1758), are invasive in some regions. They host a diverse range of blood and ectoparasites yet face minimal conservation concerns. We aimed to standardize the ex situ husbandry of R. horribilis under conditions that differed from its native habitat, successfully maintaining them for a period of 2 years. We describe optimal care protocols and present a case study monitoring trypanosome presence. Our findings support R. horribilis as a valuable model for studying amphibian pathogens. Their manageable size, non-lethal blood collection, broad distribution, and natural susceptibility to infections make them ideal for long-term research in physiology, ethology, microbiology, and parasitology. This model could facilitate studies on Batrachochytrium dendrobatidis (Bd) and blood parasites, advancing conservation efforts for endangered species.