Amphibian chytridiomycosis, a lethal pandemic disease caused by the killer fungus Batrachochytrium dendrobatidis: New approaches to host defense mechanisms and techniques for detection and monitoring

Abstract

Chytridiomycosis is a catastrophic disease currently decimating worldwide amphibian populations, caused by the panzootic chytrid fungus Batrachochytrium dendrobatidis. Massive species decline to extinction catalyzes radical changes in ecosystems globally, including the largest continuous rainforest ecosystem on Earth, the Amazon rainforest. Innovative research that aims to propose feasible mechanisms of mitigation and the origins of the disease is vital, including studies addressing climatic effects on the expansion of chytridiomycosis. Thus, this publication aims to provide a comprehensive review of: i) the current technologies used for B. dendrobatidis detection and monitoring, and ii) the known Neotropical amphibian's skin microbiota with anti-fungal properties against B. dendrobatidis. Several immunologic and DNA-based methods are discussed to understand the emerging fungal pathogens and their effects on the biosphere, which can help to mitigate the devastating ecological impacts of mass amphibian morbidity. The establishment of rapid and highly accurate B. dendrobatidis detection techniques and methods for monitoring amphibian's cutaneous microbiome is crucial in the fight against chytridiomycosis.

Field-based molecular detection of Batrachochytrium dendrobatidis in critically endangered Atelopus toads and aquatic habitats in Ecuador

“…Bd transmission occurs through animal contact or via waterborne motile zoospores [ 10 ]. Detection of Bd in amphibian hosts, including larvae, metamorphs, and adults, is achieved through various methods.…”

Exploring Differing Host Cutaneous Microbiome and Immune Responses Contributing to Chytridiomycosis Susceptibility in Amphibians

“…The disease was observed in the 1970's and formally described by scientists in 1998. The origins of this disease are still debated, with scientists claiming it originated from Africa 1 or Asia 2 . Chytridiomycosis is now thought to be responsible for the severe decline and extinction of amphibian species such as Rheobatrachus vitellinus and Rheobatrachus silus (northern and southern gastric brooding frogs) in Australia 1 .…”

“…Chytridiomycosis has spread globally, now primarily affecting amphibians in Europe, Australia, and the Americas. Some species or populations such as Litoria verreauxii, a vulnerable Australian species, are susceptible to the disease whilst others such as Rhinella marina 1 , a common cane toad, remain unaffected 2 . Amphibians cannot be grouped into affected and non-affected species, as susceptibility variations can occur intra-species.…”