A Global Review of the Zoonotic Potential and Disease Risks of Amphibian Parasites in Bullfrog Aquaculture

Abstract

Amphibians are a diverse group of tetrapod vertebrates comprising three orders: Anura, Caudata, and Gymnophiona, which play important roles in worldwide ecosystems. Over the past 40 years, amphibian populations have sharply declined and some of them are even endangered. Specifically, it is estimated that 35 species have gone extinct, while 653 species are considered critically endangered, and 55 species are data deficient. Infectious diseases are a significant contributor to amphibian declines, with parasites being a key driving factor. A comprehensive understanding of amphibian parasites and their pathogenicity is essential for elucidating their detrimental effects on wild amphibian populations and potential risk for cultured frogs. This review summarizes the reported amphibian parasites globally, focusing on the notable pathogens that threaten the health of these populations. More than 1600 species across 19 taxa have been recorded, including 16 amoebae species, 147 apicomplexans, 86 ciliates, 52 euglena, 17 mesomycetozoans, 30 metamonads, 92 Opalinata, 11 perkinsus, 9 microsporidia, 31 myxozoans, 105 acanthocephalans, 91 cestodes, 310 trematodes, 11 monopisthocotyla, 125 polyopisthocotyla, 427 nematodes, 19 pentastomids, 11 branchiura, and 10 copepods. Their pathology and potential disease risks in bullfrog aquaculture were fully documented. Finally, their possible zoonotic risk and the potential for wild amphibian population declines are discussed. Conclusively, the consumption custom, cooking culture, increasing awareness of unscientific medical usage of frog meat and skin, and application of zoonotic parasites' transmission biology-based healthy aquaculture models and techniques determine the extremely low zoonotic risk of edible cultured bullfrogs.