Dataset Information

Development of Snake Fungal Disease after Experimental Challenge with Ophidiomyces ophiodiicola in Cottonmouths (Agkistrodon piscivorous).

ABSTRACT: Snake fungal disease (SFD) is a clinical syndrome associated with dermatitis, myositis, osteomyelitis, and pneumonia in several species of free-ranging snakes in the US. The causative agent has been suggested as Ophidiomyces ophiodiicola, but other agents may contribute to the syndrome and the pathogenesis is not understood. To understand the role of O. ophiodiicola in SFD, a cottonmouth snake model of SFD was designed. Five cottonmouths (Agkistrodon piscivorous) were experimentally challenged by nasolabial pit inoculation with a pure culture of O. ophiodiicola. Development of skin lesions or facial swelling at the site of inoculation was observed in all snakes. Twice weekly swabs of the inoculation site revealed variable presence of O. ophiodiicola DNA by qPCR in all five inoculated snakes for 3 to 58 days post-inoculation; nasolabial flushes were not a useful sampling method for detection. Inoculated snakes had a 40% mortality rate. All inoculated snakes had microscopic lesions unilaterally on the side of the swabbed nasolabial pit, including erosions to ulcerations and heterophilic dermatitis. All signs were consistent with SFD; however, the severity of lesions varied in individual snakes, and fungal hyphae were only observed in 3 of 5 inoculated snakes. These three snakes correlated with post-mortem tissue qPCR evidence of O. ophiodiicola. The findings of this study conclude that O. ophiodiicola inoculation in a cottonmouth snake model leads to disease similar to SFD, although lesion severity and the fungal load are quite variable within the model. Future studies may utilize this model to further understand the pathogenesis of this disease and develop management strategies that mitigate disease effects, but investigation of other models with less variability may be warranted.

SUBMITTER: Allender MC

PROVIDER: S-EPMC4607413 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Publications

Development of Snake Fungal Disease after Experimental Challenge with Ophidiomyces ophiodiicola in Cottonmouths (Agkistrodon piscivorous).

Allender Matthew C MC Baker Sarah S Wylie Daniel D Loper Daniel D Dreslik Michael J MJ Phillips Christopher A CA Maddox Carol C Driskell Elizabeth A EA

PloS one 20151015 10

Snake fungal disease (SFD) is a clinical syndrome associated with dermatitis, myositis, osteomyelitis, and pneumonia in several species of free-ranging snakes in the US. The causative agent has been suggested as Ophidiomyces ophiodiicola, but other agents may contribute to the syndrome and the pathogenesis is not understood. To understand the role of O. ophiodiicola in SFD, a cottonmouth snake model of SFD was designed. Five cottonmouths (Agkistrodon piscivorous) were experimentally challenged b ...[more]

PMID: 26469977

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Project description:Emerging infectious diseases (EIDs) are typically characterized by novelty (recent detection) and by increasing incidence, distribution, and/or pathogenicity. Ophidiomycosis, also called snake fungal disease, is caused by the fungus Ophidiomyces ophidiicola (formerly "ophiodiicola"). Ophidiomycosis has been characterized as an EID and as a potential threat to populations of Nearctic snakes, sparking over a decade of targeted research. However, the severity of this threat is unclear. We reviewed the available literature to quantify incidence and effects of ophidiomycosis in Nearctic snakes, and to evaluate whether the evidence supports the ongoing characterization of ophidiomycosis as an EID. Data from Canada remain scarce, so we supplemented the literature review with surveys for O. ophidiicola in the Canadian Great Lakes region. Peer-reviewed reports of clinical signs consistent with ophidiomycosis in free-ranging, Nearctic snakes date back to at least 1998, and retrospective molecular testing of samples extend the earliest confirmed record to 1986. Diagnostic criteria varied among publications (n = 33), confounding quantitative comparisons. Ophidiomycosis was diagnosed or suspected in 36/121 captive snakes and was fatal in over half of cases (66.7%). This result may implicate captivity-related stress as a risk factor for mortality from ophidiomycosis, but could also reflect reporting bias (i.e., infections are more likely to be detected in captive snakes, and severe cases are more likely to be reported). In contrast, ophidiomycosis was diagnosed or suspected in 441/2,384 free-ranging snakes, with mortality observed in 43 (9.8 %). Ophidiomycosis was only speculatively linked to population declines, and we found no evidence that the prevalence of the pathogen or disease increased over the past decade of targeted research. Supplemental surveys and molecular (qPCR) testing in Ontario, Canada detected O. ophidiicola on 76 of 657 free-ranging snakes sampled across ~136,000 km2. The pathogen was detected at most sites despite limited and haphazard sampling. No large-scale mortality was observed. Current evidence supports previous suggestions that the pathogen is a widespread, previously unrecognized endemic, rather than a novel pathogen. Ophidiomycosis may not pose an imminent threat to Nearctic snakes, but further research should investigate potential sublethal effects of ophidiomycosis such as altered reproductive success that could impact population growth, and explore whether shifting environmental conditions may alter host susceptibility.

Dataset Information

Development of Snake Fungal Disease after Experimental Challenge with Ophidiomyces ophiodiicola in Cottonmouths (Agkistrodon piscivorous).

Publications

Development of Snake Fungal Disease after Experimental Challenge with Ophidiomyces ophiodiicola in Cottonmouths (Agkistrodon piscivorous).

Similar Datasets

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