Chytridiomycosis related mortality in a midwife toad (Alytes obstetricans) in Belgium

Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis, contributes to amphibian declines worldwide. Recently, the fungus has shown to be widely distributed in Belgium and the Netherlands, although no clinical cases of the disease have been diagnosed yet. This case report describes the first case of mortality due to chytridiomycosis in Belgium in a wild population of midwife toads (Alytes obstetricans). The presence of clinical chytridiomycosis, combined with the relatively high prevalence of the fungus in Belgium, emphasizes the urgent need for a thorough study on the impact of infection on the native amphibian populations in Belgium

Antibacterial therapeutics for the treatment of chytrid infection in amphibians: Columbus’s egg?

<p>Abstract</p> <p>Background</p> <p>The establishment of safe and effective protocols to treat chytridiomycosis in amphibians is urgently required. In this study, the usefulness of antibacterial agents to clear chytridiomycosis from infected amphibians was evaluated.</p> <p>Results</p> <p>Florfenicol, sulfamethoxazole, sulfadiazine and the combination of trimethoprim and sulfonamides were active <it>in vitro</it> against cultures of five <it>Batrachochytrium dendrobatidis</it> strains containing sporangia and zoospores, with minimum inhibitory concentrations (MIC) of 0.5-1.0 μg/ml for florfenicol and 8.0 μg/ml for the sulfonamides. Trimethoprim was not capable of inhibiting growth but, combined with sulfonamides, reduced the time to visible growth inhibition by the sulfonamides. Growth inhibition of <it>B. dendrobatidis</it> was not observed after exposure to clindamycin, doxycycline, enrofloxacin, paromomycin, polymyxin E and tylosin. Cultures of sporangia and zoospores of <it>B. dendrobatidis</it> strains JEL423 and IA042 were killed completely after 14 days of exposure to 100 μg/ml florfenicol or 16 μg/ml trimethoprim combined with 80 μg/ml sulfadiazine. These concentrations were, however, not capable of efficiently killing zoospores within 4 days after exposure as assessed using flow cytometry. Florfenicol concentrations remained stable in a bathing solution during a ten day period. Exposure of <it>Discoglossus scovazzi</it> tadpoles for ten days to 100 μg/ml but not to 10 μg florfenicol /ml water resulted in toxicity. In an <it>in vivo</it> trial, post metamorphic <it>Alytes muletensis</it>, experimentally inoculated with <it>B. dendrobatidis,</it> were treated topically with a solution containing 10 μg/ml of florfenicol during 14 days. Although a significant reduction of the <it>B. dendrobatidis</it> load was obtained, none of the treated animals cleared the infection.</p> <p>Conclusions</p> <p>We thus conclude that, despite marked anti <it>B. dendrobatidis</it> activity <it>in vitro</it>, the florfenicol treatment used is not capable of eliminating <it>B. dendrobatidis</it> infections from amphibians.</p