Tracking Outcomes of Snake Fungal Disease in Free-ranging Pygmy Rattlesnakes (<i>Sistrurus miliarius</i>)

Lind, Craig; McCoy, Ciera M.; Farrell, Terence M.

doi:10.7589/2017-05-109

Cited by 29 publications

(28 citation statements)

References 14 publications

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“…Further research is required to determine the relative importance of these factors and others such as host taxonomy, life history, habitat degradation, food availability, environmental conditions (eg, temperature), season, and stress, as well as inoculation route and dose on disease development. 4,17,23,24,26,27,29…”

Section: Discussionmentioning

confidence: 99%

“…17,24,26,40 However, the relative effects of brumation, environmental temperature, and nutritional status on the pathogenesis of ophidiomycosis, including aspects of transmission, are unknown. 23,26 Ophidiomyces ophiodiicola was demonstrated as the causative agent of fungal disease in snakes through experimental studies using 2 different models. 2,27 The first study introduced the fungus into the nasolabial pits of cottonmouths (Agkistrodon piscivorus) using a catheter.…”

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confidence: 99%

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Ophidiomycosis in Red Cornsnakes (Pantherophis guttatus): Potential Roles of Brumation and Temperature on Pathogenesis and Transmission

et al. 2020

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Ophidiomycosis (snake fungal disease) is caused by the fungus Ophidiomyces ophiodiicola. As ophidiomycosis is difficult to study in free-ranging snakes, a reliable experimental model is needed to investigate transmission, pathogenesis, morbidity, and mortality, and the effects of brumation and temperature on disease development. Our objective was to develop such a model via subcutaneous injection of O. ophiodiicola conidia in red cornsnakes ( Pantherophis guttatus). The model was used to evaluate transmission and the effects of brumation and temperature in co-housed inoculated and noninoculated snakes. All 23 inoculated snakes developed lesions consistent with ophidiomycosis, including heterophilic and granulomatous dermatitis, cellulitis, and myositis, and embolic fungal granulomas throughout the liver and the coelomic connective tissue in 21/23 (91%). In the inoculated snakes, 21% of skin swabs, 37% of exuvia, and all liver samples tested positive by qPCR (quantitative polymerase chain reaction) for O. ophiodiicola. A post brumation skin swab from 1/12 noninoculated snakes that brumated in contact with inoculated snakes tested positive by qPCR, suggesting possible contact transmission. That snake had microscopic skin lesions consistent with ophidiomycosis, but no visible fungal elements. Of the 23 inoculated snakes, 20 (87%) died over the 70-day experiment, with ophidiomycosis considered the primary cause of death; 12 (52%) of the inoculated snakes died during brumation. Overall, this experimental model of ophidiomycosis reproduced skin lesions analogous to those of many natural cases, and internal lesions similar to the most severe natural cases. The study provides tentative experimental evidence for horizontal transmission in brumation, and offers a tool for future studies of this widespread snake disease.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Ophidiomycosis in Red Cornsnakes (Pantherophis guttatus): Potential Roles of Brumation and Temperature on Pathogenesis and Transmission

et al. 2020

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“…Snake Fungal Disease (SFD) is caused by a severe cutaneous infection with the fungus Ophidiomyces ophiodiicola and was first seen in North America in 2006 [ 2 ]. This fungus has since been observed infecting the epidermis of 23 snake species, causing severe SFD and mortality in at least 3 of them [ 3 ], although one other snake species readily recovers from this cutaneous infection [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

The Antifungal Properties of Epidermal Fatty Acid Esters: Insights from White-Nose Syndrome (WNS) in Bats

et al. 2018

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Numerous free fatty acids (FFAs) are known to have potent antifungal effects. The mammalian epidermis contains both FFAs and multiple classes of fatty acid esters, including 1-monoacylglycerols and wax esters. We thus hypothesized that wax esters and 1-monoacylglycerols composed of antifungal fatty acids would also have antifungal properties. We tested this hypothesis by examining the effects of 1-monoacylglycerols, 1,3-diacylglycerols, and wax esters on the growth of Pseudogymnoascus destructans (Pd), the fungus that causes White-nose Syndrome (WNS) in North American bats by invading their epidermis. Laboratory experiments with Pd cultures demonstrated that: (a) three 1-monoacylglycerols (1-monopalmitolein, 1-monoolein, and 1-monolinolein), as well as, (b) two wax esters, behenyl oleate and behenyl palmitoleate, profoundly inhibit Pd growth. The normal growth cycle of Pd was interrupted by addition of two cholesterol esters to the media as well. A bat species resistant to cutaneous Pd infections has these 1-monoacylglycerols in the epidermis, and another Pd resistant bat species has these wax esters in the sebum, thus cutaneous lipid composition is one factor which enables some bats to avoid WNS. Our experiments also revealed that the fatty acid esters which inhibit Pd growth are not hydrolyzed by the lipases secreted by this fungus, whereas the esters that do not inhibit Pd growth are hydrolyzed.

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“…Recently, several investigations have been conducted determining the physiological impact of ophidiomycosis on pygmy rattlesnakes ( Sistrurus miliarius ) in Florida. Specifically, snakes with ophidiomycosis have shown a decrease in body condition with increasing severity of infection, but severity was not associated with recapture rate, and severely affected snakes apparently cleared infection [ 54 ]. It was also observed that the resting metabolic rate in this species was increased in ophidiomycosis-positive individuals, which may contribute to declining individual health during the disease process [ 55 ].…”

Section: Discussionmentioning

confidence: 99%

Ophidiomycosis, an emerging fungal disease of snakes: Targeted surveillance on military lands and detection in the western US and Puerto Rico

et al. 2020

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Wildlife disease surveillance and pathogen detection are fundamental for conservation, population sustainability, and public health. Detection of pathogens in snakes is often overlooked despite their essential roles as both predators and prey within their communities. Ophidiomycosis (formerly referred to as Snake Fungal Disease, SFD), an emergent disease on the North American landscape caused by the fungus Ophidiomyces ophiodiicola , poses a threat to snake population health and stability. We tested 657 individual snakes representing 58 species in 31 states from 56 military bases in the continental US and Puerto Rico for O . ophiodiicola . Ophidiomyces ophiodiicola DNA was detected in samples from 113 snakes for a prevalence of 17.2% (95% CI: 14.4–20.3%), representing 25 species from 19 states/territories, including the first reports of the pathogen in snakes in Idaho, Oklahoma, and Puerto Rico. Most animals were ophidiomycosis negative (n = 462), with Ophidiomyces detected by qPCR (n = 64), possible ophidiomycosis (n = 82), and apparent ophidiomycosis (n = 49) occurring less frequently. Adults had 2.38 times greater odds than juveniles of being diagnosed with ophidiomycosis. Snakes from Georgia, Massachusetts, Pennsylvania, and Virginia all had greater odds of ophidiomycosis diagnosis, while snakes from Idaho were less likely to be diagnosed with ophidiomycosis. The results of this survey indicate that this pathogen is endemic in the eastern US and identified new sites that could represent emergence or improved detection of endemic sites. The direct mortality of snakes with ophidiomycosis is unknown from this study, but the presence of numerous individuals with clinical disease warrants further investigation and possible conservation action.

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Tracking Outcomes of Snake Fungal Disease in Free-ranging Pygmy Rattlesnakes (Sistrurus miliarius)

Cited by 29 publications

References 14 publications

Ophidiomycosis in Red Cornsnakes (Pantherophis guttatus): Potential Roles of Brumation and Temperature on Pathogenesis and Transmission

Ophidiomycosis in Red Cornsnakes (Pantherophis guttatus): Potential Roles of Brumation and Temperature on Pathogenesis and Transmission

The Antifungal Properties of Epidermal Fatty Acid Esters: Insights from White-Nose Syndrome (WNS) in Bats

Ophidiomycosis, an emerging fungal disease of snakes: Targeted surveillance on military lands and detection in the western US and Puerto Rico

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