Bullfrog farms release virulent zoospores of the frog-killing fungus into the natural environment

Autor(es)

Ribeiro, Luisa P. ^[1] ; Carvalho, Tamilie ^[1] ; Becker, C. Guilherme ^[2] ; Jenkinson, Thomas S. ^[3] ; Leite, Domingos da Silva ^[4] ; James, TimothyY ^[3] ; Greenspan, Sasha E. ^[2] ; Toledo, Luis Felipe ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Inst Biol, Lab Hist Nat Anfibios Brasileiros LaHNAB, UNICAMP, BR-13083862 Campinas, SP - Brazil

^[2] Univ Alabama, Dept Biol Sci, Tuscaloosa, AL 35487 - USA

^[3] Univ Michigan, Dept Ecol & Evolutionary Biol, Ann Arbor, MI 48109 - USA

^[4] Univ Estadual Campinas, Inst Biol, Dept Genet Evolucao Microbiol & Imunol, UNICAMP, BR-13083862 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: SCIENTIFIC REPORTS; v. 9, SEP 17 2019.
• Citações Web of Science: 0

Resumo

Bullfrog farming and trade practices are well-established, globally distributed, and economically valuable, but pose risks for biodiversity conservation. Besides their negative impacts on native amphibian populations as an invasive species, bullfrogs play a key role in spreading the frog-killing fungus Batrachochytrium dendrobatidis (Bd) in the natural environment. Bullfrogs are tolerant to Bd, meaning that they can carry high infection loads without developing chytridiomycosis. To test the potential of bullfrog farms as reservoirs for diverse and virulent chytrid genotypes, we quantified Bd presence, prevalence and infection loads across approximately 1,500 farmed bullfrogs and in the water that is released from farms into the environment. We also described Bd genotypic diversity within frog farms by isolating Bd from dozens of infected tadpoles. We observed individuals infected with Bd in all sampled farms, with high prevalence (reaching 100%) and high infection loads (average 71,029 zoospore genomic equivalents). Average outflow water volume from farms was high (60,000 L/day), with Bd zoospore concentration reaching approximately 50 million zoospores/L. Because virulent pathogen strains are often selected when growing in tolerant hosts, we experimentally tested whether Bd genotypes isolated from bullfrogs are more virulent in native anuran hosts compared to genotypes isolated from native host species. We genotyped 36 Bd isolates from two genetic lineages and found that Bd genotypes cultured from bullfrogs showed similar virulence in native toads when compared to genotypes isolated from native hosts. Our results indicate that bullfrog farms can harbor high Bd genotypic diversity and virulence and may be contributing to the spread of virulent genotypes in the natural environment. We highlight the urgent need to implement Bd monitoring and mitigation strategies in bullfrog farms to aid in the conservation of native amphibians. (AU)

• Processo FAPESP: 16/25358-3 - O fungo quitrídio no Brasil: da sua origem às suas consequências
• Beneficiário: Luis Felipe de Toledo Ramos Pereira
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 16/03344-0 - O quitrídio nos ranários do estado de São Paulo e suas implicações para conservação da fauna nativa
• Beneficiário: Luisa de Pontes Ribeiro
• Modalidade de apoio: Bolsas no Brasil - Mestrado