An investigation was conducted to determine the cause of morbidity and mortality in a collection of 55 adult male Xenopus (Silurana) tropicalis at the University of California, Berkeley. More than 80% of affected frogs died during the epizootic. All frogs were anorectic and lethargic, had dark pigmentation and excess skin sloughing, and lacked a slime layer. Histologic examination revealed severe hyperplastic and spongiotic dermatitis associated with colonization of the stratum corneum by large numbers of zoosporangia diagnostic of Batrachochytrium dendrobatidis. Treatment with a commercial formalin/malachite green solution at a dilution of 0.007 ml/L of tank water for 24 h, repeated every other day for four treatments, eliminated the organism and was curative. These findings are indicative of epidermal chytridiomycosis as a primary cause of death in this collection of X. tropicalis.
"We did not collect tissue samples for histological examination, but the animal was also lethargic. Anurans with Bd infections are often emaciated, with symptoms persisting for 2–3 months after clearing Bd infections (Parker et al. 2002). However, emaciation does not always imply a Bd infection, as anurans with parasite infections often appear emaciated (Young et al. 2012). "
"Low prevalence has been recorded in some terrestrial breeding species such as Microhylids (Kriger and Hero, 2006a) and the Pouched Frog (Assa darlingtoni) record in Kriger and Hero (2007b) but not others i.e. the Eleutherodactylids in Central and South America (Beard and O'Neill, 2005); 5. the FGF on Viwa have been exposed to Bd but they have skin defences that prevent Bd infection (Woodhams et al. 2003; Woodhams and Alford, 2005). This is unlikely as most species that are resilient still have Bd positive individuals within the population – however no clinical sign of disease (Parker et al., 2002). Many other anuran species are resilient to the pathogen and either do not become susceptible to it or have some level of population-level resistance (e.g. "
"One positive Bd record from Ghana  is often cited in the literature and has been used for ENMs , , . However, it was excluded from our ENM analysis because the specimen stems from the pet trade, has an unknown origin and was tested after being imported into the US. "
[Show abstract][Hide abstract] ABSTRACT: A putative driver of global amphibian decline is the panzootic chytrid fungus Batrachochytrium dendrobatidis (Bd). While Bd has been documented across continental Africa, its distribution in West Africa remains ambiguous. We tested 793 West African amphibians (one caecilian and 61 anuran species) for the presence of Bd. The samples originated from seven West African countries - Bénin, Burkina Faso, Côte d'Ivoire, Ghana, Guinea, Liberia, Sierra Leone - and were collected from a variety of habitats, ranging from lowland rainforests to montane forests, montane grasslands to humid and dry lowland savannahs. The species investigated comprised various life-history strategies, but we focused particularly on aquatic and riparian species. We used diagnostic PCR to screen 656 specimen swabs and histology to analyse 137 specimen toe tips. All samples tested negative for Bd, including a widespread habitat generalist Hoplobatrachus occipitalis which is intensively traded on the West African food market and thus could be a potential dispersal agent for Bd. Continental fine-grained (30 arc seconds) environmental niche models suggest that Bd should have a broad distribution across West Africa that includes most of the regions and habitats that we surveyed. The surprising apparent absence of Bd in West Africa indicates that the Dahomey Gap may have acted as a natural barrier. Herein we highlight the importance of this Bd-free region of the African continent - especially for the long-term conservation of several threatened species depending on fast flowing forest streams (Conraua alleni ("Vulnerable") and Petropedetes natator ("Near Threatened")) as well as the "Critically Endangered" viviparous toad endemic to the montane grasslands of Mount Nimba (Nimbaphrynoides occidentalis).
PLoS ONE 02/2013; 8(2):e56236. DOI:10.1371/journal.pone.0056236 · 3.23 Impact Factor
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