Ongoing Health Assessment and Prevalence of<i>Chrysosporium</i>in the Eastern Massasauga (<i>Sistrurus catenatus catenatus</i>)

Allender, Matthew C.; Dreslik, Michael J.; Wylie, Daniel B.; Wylie, Sarah J.; Scott, John W.; Phillips, Christopher A.

doi:10.1643/ot-12-004

Cited by 30 publications

(23 citation statements)

References 18 publications

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“…A culture-based survey indicated that that these fungi are rare on the skin of healthy captive squamates (6), and these results are supported by PCR assays that failed to detect the presence of O. ophiodiicola (as Chrysosporium species) in 38 wild eastern massasauga snakes that were captured for a disease investigation survey (40). In contrast, PCR assays did detect the presence of O. ophiodiicola in 9 of 14 wild timber rattlesnakes from New England that presented with skin lesions (38).…”

Section: Discussionmentioning

confidence: 99%

Molecular Characterization of Reptile Pathogens Currently Known as Members of the Chrysosporium Anamorph of Nannizziopsis vriesii Complex and Relationship with Some Human-Associated Isolates

2013

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In recent years, the Chrysosporium anamorph of Nannizziopsis vriesii (CANV), Chrysosporium guarroi, Chrysosporium ophiodiicola, and Chrysosporium species have been reported as the causes of dermal or deep lesions in reptiles. These infections are contagious and often fatal and affect both captive and wild animals. Forty-nine CANV isolates from reptiles and six isolates from human sources were compared with N. vriesii based on their cultural characteristics and DNA sequence data. Analyses of the sequences of the internal transcribed spacer and small subunit of the nuclear ribosomal gene revealed that the reptile pathogens and human isolates belong in well-supported clades corresponding to three lineages that are distinct from all other taxa within the family Onygenaceae of the order Onygenales. One lineage represents the genus Nannizziopsis and comprises N. vriesii, N. guarroi, and six additional species encompassing isolates from chameleons and geckos, crocodiles, agamid and iguanid lizards, and humans. Two other lineages comprise the genus Ophidiomyces, with the species Ophidiomyces ophiodiicola occurring only in snakes, and Paranannizziopsis gen. nov., with three new species infecting squamates and tuataras. The newly described species are Nannizziopsis dermatitidis, Nannizziopsis crocodili, Nannizziopsis barbata, Nannizziopsis infrequens, Nannizziopsis hominis, Nannizziopsis obscura, Paranannizziopsis australasiensis, Paranannizziopsis californiensis, and Paranannizziopsis crustacea. Chrysosporium longisporum has been reclassified as Paranannizziopsis longispora. N. guarroi causes yellow fungus disease, a common infection in bearded dragons and green iguanas, and O. ophiodiicola is an emerging pathogen of captive and wild snakes. Human-associated species were not recovered from reptiles, and reptile-associated species were recovered only from reptiles, thereby mitigating concerns related to zoonosis.

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Section: Discussionmentioning

confidence: 99%

Molecular Characterization of Reptile Pathogens Currently Known as Members of the Chrysosporium Anamorph of Nannizziopsis vriesii Complex and Relationship with Some Human-Associated Isolates

2013

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“…Such a baseline will inform and guide ongoing Eastern Massasauga conservation efforts, including the captive breeding program (Earnhardt et al 2011). In light of emerging fungal pathogens affecting snake populations, future work should examine the relationship between genetic variation and pathogen resistance (Bertelsen et al 2005;Allender et al 2013).…”

Section: Comparison Of Neutral and Functional Variationmentioning

confidence: 99%

Microsatellite and major histocompatibility complex variation in an endangered rattlesnake, the Eastern Massasauga (Sistrurus catenatus)

Jaeger

Duvall

Swanson

et al. 2016

Ecology and Evolution

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Genetic diversity is fundamental to maintaining the long‐term viability of populations, yet reduced genetic variation is often associated with small, isolated populations. To examine the relationship between demography and genetic variation, variation at hypervariable loci (e.g., microsatellite DNA loci) is often measured. However, these loci are selectively neutral (or near neutral) and may not accurately reflect genomewide variation. Variation at functional trait loci, such as the major histocompatibility complex (MHC), can provide a better assessment of adaptive genetic variation in fragmented populations. We compared patterns of microsatellite and MHC variation across three Eastern Massasauga (Sistrurus catenatus) populations representing a gradient of demographic histories to assess the relative roles of natural selection and genetic drift. Using 454 deep amplicon sequencing, we identified 24 putatively functional MHC IIB exon 2 alleles belonging to a minimum of six loci. Analysis of synonymous and nonsynonymous substitution rates provided evidence of historical positive selection at the nucleotide level, and Tajima's D provided support for balancing selection in each population. As predicted, estimates of microsatellite allelic richness, observed, heterozygosity, and expected heterozygosity varied among populations in a pattern qualitatively consistent with demographic history and abundance. While MHC allelic richness at the population and individual levels revealed similar trends, MHC nucleotide diversity was unexpectedly high in the smallest population. Overall, these results suggest that genetic variation in the Eastern Massasauga populations in Illinois has been shaped by multiple evolutionary mechanisms. Thus, conservation efforts should consider both neutral and functional genetic variation when managing captive and wild Eastern Massasauga populations.

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“…Snake fungal disease has now been recorded in 6 snake families representing over 30 species throughout most of the eastern half of the United States and captive snakes in parts of the United Kingdom, Germany, and Australia (Tetzlaff et al , Allender et al , Lorch et al ). Mortalities due to SFD have been reported for several snake species (Allender et al , Sigler et al , Sleeman ). However, a population‐level response (decline) where SFD was suspected (along with other contributing factors such as inbreeding depression and high summer rainfall) has been documented only once, in a New Hampshire population of timber rattlesnakes ( Crotalus horridus ; Clark et al ).…”

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Estimation of Ophidiomyces prevalence to evaluate snake fungal disease risk

et al. 2017

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Pathogenic fungi have become a global concern to wildlife populations over the last 2 decades. However, the threat of snake fungal disease (SFD; caused by Ophidiomyces ophiodiicola) to snake populations is still largely unknown. From 2014-2016, we monitored 3 disjunct populations of the federally threated eastern massasauga (Sistrurus catenatus) in Michigan, USA. We used clinical signs of SFD, quantitative TaqMan polymerase chain reaction (qPCR), repeated sampling of individuals and sites, and single-season occupancy models to estimate site-specific prevalence of Ophidiomyces. Point estimates of Ophidiomyces prevalence in 2016 were larger at the northernmost study site (0.17, 95% CI ¼ 0.04-0.50), where 17 of 34 snakes were implanted with radio-transmitters, and smaller at southern sites (0.03, 95% CI ¼ 0.00-0.19). However, Ophidiomyces prevalence was not different between snakes with transmitters and snakes without transmitters. Swabbing snakes with 1 applicator resulted in a high probability of failure in detecting Ophidiomyces DNA for individuals with clinical signs of SFD and the probability was even higher for individuals without clinical signs of SFD. Repeated sampling of individuals reduced the probability of obtaining a false-negative qPCR result by 72% for snakes with clinical signs and 12% for snakes without clinical signs when we swabbed individuals with 5 applicators. We recommend resampling individuals and sites as a sampling design for estimating fine-scale, site-specific Ophidiomyces prevalence and population-level responses to SFD. If clinical signs are used as a surrogate for SFD, we recommend researchers standardize diagnosis of clinical signs of SFD by providing technicians adequate field training and educational materials, and minimize the number of observers recording clinical signs. We discourage the use of radio-telemetry methods where SFD occurs unless sterile surgical, handling, and equipment protocols can be ensured and the benefits to the population from such activities outweigh the increased health risks to individuals. Ó 2017 The Wildlife Society.

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Ongoing Health Assessment and Prevalence ofChrysosporiumin the Eastern Massasauga (Sistrurus catenatus catenatus)

Cited by 30 publications

References 18 publications

Molecular Characterization of Reptile Pathogens Currently Known as Members of the Chrysosporium Anamorph of Nannizziopsis vriesii Complex and Relationship with Some Human-Associated Isolates

Molecular Characterization of Reptile Pathogens Currently Known as Members of the Chrysosporium Anamorph of Nannizziopsis vriesii Complex and Relationship with Some Human-Associated Isolates

Microsatellite and major histocompatibility complex variation in an endangered rattlesnake, the Eastern Massasauga (Sistrurus catenatus)

Estimation of Ophidiomyces prevalence to evaluate snake fungal disease risk

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