Efficacy of F10 against amphibian chytrid fungus

MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Outbreaks of pathogens that threaten both human and nature have increased in recent years. Infectious and transmittable diseases, such as chytridiomycosis, which is caused by the emerging pathogen Batrachochytrium dendrobatidis, has been identified as one of the most important drivers of the current declines in amphibian numbers. This pathogen has spread globally and is not only responsible for the declines in amphibian population numbers, but also for the extinction of species in several countries. As part of the Amphibian Conservation Action Plan, the IUCN recommended ex situ breeding of amphibian species to try and stem the global loss of amphibian species. Due to chytridiomycosis being one of the most eminent threats for amphibians, it poses an additional threat for the ex situ breeding plan. There is thus a need for safe and effective measures to treat chytridiomycosis, especially in breeding programs for endangered species. F10 (Health and Hygiene) is a veterinary antiseptic that has shown to be 100% effective in killing B. Dendrobatidis in vitro. Before any chemical treatment can be applied the efficacy and toxicity of F10 has to be determined to establish if F10 can be effectively applied across different amphibian species and across different life stages. We propose to develop a treatment protocol for F10 for the effective treatment of amphibian chytridiomycosis by challenging juveniles of Amietophrynus gutturalis with B. dendrobatidis and subsequently treating the infection with a proposed concentration of F10. The survival of B. dendrobatidis zoospores was also determined in the presence of F10. The results obtained showed survival of tadpoles at a 1:10,000 concentration of F10 for 30min, and juveniles at a concentration of 1:2000 for 15 min. Furthermore the in vitro tests showed that the B. dendrobatidis zoospores died after 10 min at a 1:10,000 concentration and 30 min at a 1:15,000 concentration. The successful treatment of tadpoles as well as juveniles will increase any species chance for survival, especially when treating tadpoles as the pathogen will then be eradicated before the tadpole metamorphoses and reaches the disease-susceptible life stage. By establishing a partnership between the industry, academic and zoo/wildlife communities we hope to maximise the likelihood of implementing this program in the future and thus ensuring long term sustainability.

Masters