Explore the vast range of titles available.

Snake fungal disease (SFD) is an emerging skin infection of wild snakes in eastern North America. The fungus Ophidiomyces ophiodiicola is frequently associated with the skin lesions that are characteristic of SFD, but a causal relationship between the fungus and the disease has not been established. We experimentally infected captive-bred corn snakes ( Pantherophis guttatus ) in the laboratory with pure cultures of O. ophiodiicola . All snakes in the infected group ( n = 8) developed gross and microscopic lesions identical to those observed in wild snakes with SFD; snakes in the control group ( n = 7) did not develop skin infections. Furthermore, the same strain of O. ophiodiicola used to inoculate snakes was recovered from lesions of all animals in the infected group, but no fungi were isolated from individuals in the control group. Monitoring progression of lesions throughout the experiment captured a range of presentations of SFD that have been described in wild snakes. The host response to the infection included marked recruitment of granulocytes to sites of fungal invasion, increased frequency of molting, and abnormal behaviors, such as anorexia and resting in conspicuous areas of enclosures. While these responses may help snakes to fight infection, they could also impact host fitness and may contribute to mortality in wild snakes with chronic O. ophiodiicola infection. This work provides a basis for understanding the pathogenicity of O. ophiodiicola and the ecology of SFD by using a model system that incorporates a host species that is easy to procure and maintain in the laboratory. IMPORTANCE Skin infections in snakes, referred to as snake fungal disease (SFD), have been reported with increasing frequency in wild snakes in the eastern United States. While most of these infections are associated with the fungus Ophidiomyces ophiodiicola , there has been no conclusive evidence to implicate this fungus as a primary pathogen. Furthermore, it is not understood why the infections affect different host populations differently. Our experiment demonstrates that O. ophiodiicola is the causative agent of SFD and can elicit pathological changes that likely impact fitness of wild snakes. This information, and the laboratory model we describe, will be essential in addressing unresolved questions regarding disease ecology and outcomes of O. ophiodiicola infection and helping to conserve snake populations threatened by the disease. The SFD model of infection also offers utility for exploring larger concepts related to comparative fungal virulence, host response, and host-pathogen evolution. Skin infections in snakes, referred to as snake fungal disease (SFD), have been reported with increasing frequency in wild snakes in the eastern United States. While most of these infections are associated with the fungus Ophidiomyces ophiodiicola , there has been no conclusive evidence to implicate this fungus as a primary pathogen. Furthermore, it is not understood why the infections affect different host populations differently. Our experiment demonstrates that O. ophiodiicola is the causative agent of SFD and can elicit pathological changes that likely impact fitness of wild snakes. This information, and the laboratory model we describe, will be essential in addressing unresolved questions regarding disease ecology and outcomes of O. ophiodiicola infection and helping to conserve snake populations threatened by the disease. The SFD model of infection also offers utility for exploring larger concepts related to comparative fungal virulence, host response, and host-pathogen evolution.

Pathogenic fungi are increasingly associated with epidemics in wildlife populations. Snake fungal disease (SFD, also referred to as Ophidiomycosis) is an emerging threat to snakes, taxa that are elusive and difficult to sample. Thus, assessments of the effects of SFD on populations have rarely occurred. We used a field technique to enhance detection, Passive Integrated Transponder (PIT) telemetry, and a multi-state capture–mark–recapture model to assess SFD effects on short-term (within-season) survival, movement, and surface activity of two wild snake species, Regina septemvittata (Queensnake) and Nerodia sipedon (Common Watersnake). We were unable to detect an effect of disease state on short-term survival for either species. However, we estimated Bayesian posterior probabilities of >0.99 that R. septemvittata with SFD spent more time surface-active and were less likely to permanently emigrate from the study area. We also estimated probabilities of 0.98 and 0.87 that temporary immigration and temporary emigration rates, respectively, were lower in diseased R. septemvittata. We found evidence of elevated surface activity and lower temporary immigration rates in diseased N. sipedon, with estimated probabilities of 0.89, and found considerably less support for differences in permanent or temporary emigration rates. This study is the first to yield estimates for key demographic and behavioral parameters (survival, emigration, surface activity) of snakes in wild populations afflicted with SFD. Given the increase in surface activity of diseased snakes, future surveys of snake populations could benefit from exploring longer-term demographic consequences of SFD and recognize that disease prevalence in surface-active animals may exceed that of the population as a whole.

Ophidiomycosis (snake fungal disease) is caused by the fungal pathogen Ophidiomyces ophidiicola , which causes dermal lesions, occasional systemic infections, and in some cases, mortality. To better understand potential conservation implications of ophidiomycosis (i.e., population-level effects), we investigated its impacts on individual fitness in a population of endangered eastern foxsnakes ( Pantherophis vulpinus ). We tracked 38 foxsnakes over 6 years and quantified body condition, movement patterns, oviposition rates, and survival. Body condition, distance travelled, and oviposition rates were similar between snakes with and without ophidiomycosis. Interestingly, snakes that tested positive for the pathogen travelled farther, suggesting that movement through a greater diversity of habitats increases risk of exposure. Ophidiomycosis did not negatively affect survival, and most apparently infected snakes persisted in a manner comparable to snakes without ophidiomycosis. Only one mortality was directly attributed to ophidiomycosis, although infected snakes were overrepresented in a sample of snakes killed by predators. Overall, our results suggest that ophidiomycosis may have sublethal effects on eastern foxsnakes, but do not suggest direct effects on survival, ovipositioning, or viability of the study population.

Emerging pathogenic fungi have become a topic of conservation concern due to declines observed in several host taxa. One emerging fungal pathogen, Ophidiomyces ophidiicola , is well documented as the causative agent of ophidiomycosis, otherwise known as snake fungal disease (SFD). O . ophidiicola has been found to cause disease in a variety of snake species across the United States, including the eastern massasauga ( Sistrurus catenatus ), a federally threatened rattlesnake species. Most work to date has involved detecting O . ophidiicola for diagnosis of infection through direct sampling of snakes, and attempts to detect O . ophidiicola in the abiotic environment to better understand its distribution, seasonality, and habitat associations are lacking. We collected topsoil and groundwater samples from four macrohabitat types across multiple seasons in northern Michigan at a site where Ophidiomyces infection has been confirmed in eastern massasauga. Using a quantitative PCR (qPCR) assay developed for O . ophidiicola , we detected Ophidiomyces DNA in topsoil but observed minimal to no detection in groundwater samples. Detection frequency did not differ between habitats, but samples grouped seasonally showed higher detection during mid-summer. We found no relationships of detection with hypothesized environmental correlates such as soil pH, temperature, or moisture content. Furthermore, the distribution of Ophidiomyces positive samples across the site was not linked to estimated space use of massasaugas. Our data suggests that season has some effect on the presence of Ophidiomyces . Differences in presence between habitats may exist but are likely more dependent on the time of sampling and currently uninvestigated soil or biotic parameters. These findings build on our understanding of Ophidiomyces ecology and epidemiology to help inform where and when snakes may be exposed to the fungus in the environment.

Ophidiomycosis (snake fungal disease) is caused by the fungus Ophidiomyces ophiodiicola and threatens snake health worldwide. It has been documented throughout the eastern United States and severe cases have recently been reported in Georgia, USA. To evaluate disease distribution and prevalence in this state, 786 free-ranging snakes were examined for skin lesions consistent with ophidiomycosis and swabbed to detect O. ophiodiicola DNA using qPCR. Sampled snakes represented 34 species and 4 families; 27.5% had skin lesions, 13.3% were positive for O. ophiodiicola DNA, and 77.8% of the qPCR positive individuals had skin lesions. This is the first report of O. ophiodiicola in five of the 22 species that were qPCR positive. Multinomial logistic regression modeling indicated that Drymarchon couperi had a higher relative risk of apparent ophidiomycosis (lesions present and qPCR positive), and the best models predicting qPCR result and ophidiomycosis category included individual factors and excluded temporal and spatial factors. Phylogeny-based bipartite network analysis showed that Nerodia erythrogaster , Nerodia taxispilota , and D. couperi had the highest prevalence of apparent ophidiomycosis; this category was more prevalent in the subfamily Colubrinae and less prevalent in Natricinae. These results provide important information about ophidiomycosis epidemiology, which has implications for snake conservation.

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.

Ophidiomycosis is an emerging infectious disease caused by the fungus Ophidiomyces ophidiicola (Oo). To date, Oo presence or associated disease condition has been recorded in wild and/or captive snakes from North America, Europe, Asia and Australia, but the data is still scarce outside the Nearctic. Although Italy is a country with a high snake biodiversity in the European panorama, and animals with clinical signs compatible with Oo infection have been documented, to date no investigations have reported the disease in the wild. Therefore, a pilot survey for the Italian territory was performed in conjunction with setting up a complete diagnostic workflow including SYBR Green-based real-time PCR assay for the detection of Oo genomic and mitochondrial DNA combined with histopathology of scale clips. Oo presence was investigated in 17 wild snake specimens from four different species. Four snakes were sampled in a targeted location where the mycosis was suspected via citizen science communications (i.e. North of the Lake Garda), whereas other ophidians were collected following opportunistic sampling. Oo genomic and mitochondrial DNA were detected and sequenced from all four Lake Garda Natrix tessellata, including three juveniles with macroscopic signs such as discolouration and skin crusts. From histopathological examination of scale clips, the three young positive individuals exhibited ulceration, inflammation and intralesional hyphae consistent with Oo infection, and two of them also showed the presence of arthroconidial tufts and solitary cylindrical arthrospores, allowing “Ophidiomycosis and Oo shedder” categorisation. For the remaining snake samples, the real-time PCR tested negative for Oo. This pilot survey permitted to localise for the first time Oo infection in free-ranging ophidians from Italy. Ophidiomycosis from Lake Garda highlights the need to increase sampling efforts in this area as well as in other northern Italian lakes to assess the occurrence of the pathogen, possible risk factors of the infection, its impact on host population fitness and the disease ecology of Oo in European snakes.

Ophidiomyces ophidiicola, the agent of ophidiomycosis, has recently been reported in wild snakes in Italy, but the status of captive populations remains unknown. We carried out an opportunistic survey of pet snakes from private collections and, in parallel, performed an exploratory evaluation of a droplet digital PCR (ddPCR) assay adapted from an established probe-based real-time PCR. Non-invasive skin swabs were collected by 32 private owners from 97 snakes, representing 31 species across ten Italian regions. All swabs tested negative for O. ophidiicola by both methods, including samples from four snakes that showed cutaneous lesions at the time of sampling. Both assays yielded consistent amplification up to the 1:1000 dilution (ddPCR 0.38 to 0.94 copies/µL for the culture-derived control and 0.24 to 0.33 copies/µL for the field-derived control at 1:1000), while ddPCR retained positive partitions in some replicates at higher dilutions (up to 1:8000). These results provide preliminary screening data for O. ophidiicola in an opportunistic sample of Italian pet snakes and suggest potential applicability of ddPCR as a complementary tool for low-template diagnostics, while highlighting the need for larger, standardised surveys and formal assay validation.

Ophidiomyces ophidiicola, the fungus causing Snake Fungal Disease (SFD) or ophidiomycosis, is prevalent in North American snakes and can have deleterious population effects. Northern pine snakes (Pituophis melanoleucus melanoleucus) in New Jersey often test positive for ophidiomycosis. In this paper, we use qPCR to examine changes in prevalence from 2018 to 2023, and differences by age, sex, and morphological sampling locations. We swabbed ventral surfaces, head, and cloaca of snakes, and lesions and eyes if there were clinical ophidiomycosis signs. A snake was considered positive if any site was positive by qPCR. The prevalence was 47% (2018), increased to 100% (2022), but declined to 46% in 2023. The prevalence was highest in snakes with lesions (46–100%); head swabs had the lowest rates. The more lesions a snake had, the more likely it was that at least one would be positive. Males had significantly more lesions than females, but the prevalence was similar. In 2023, the prevalence of O. ophidiicola was low, but the prevalence of lesions did not decrease as markedly. We discuss the temporal changes in the positivity for O. ophidiicola and its implications for ophidiomycosis effects, suggesting that the fungus is endemic in this population.

Ophidiomycosis, caused by the keratinophilic fungus Ophidiomyces ophidiicola (Oo), is an emerging threat to snake populations, yet its epidemiology in Europe remains underexplored. We investigated the distribution of Oo across free-ranging snake populations in Italy, integrating both recent field samples and historical museum specimens. Our survey involved 423 snakes representing 17 species from 17 regions, with Oo detected in 32 snakes from five different species. Additional molecular detection for Parananniziopsis spp. on a subset of 13 Oo-negative samples from snakes that exhibited clinical signs yielded negative results. Acknowledging the non-standardised sampling and the limited sample size, our findings highlight Oo’s persistent and widespread presence across diverse ecological zones, particularly affecting semi-aquatic species like Natrix tessellata. While Oo Clade I was primarily found in museum specimens, indicating a historical presence, Clade II prevailed in recent samples. This highlights a complex epidemiological landscape where different clades may influence the current disease dynamics. Our results underscore the importance of continuous surveillance and highlight the need for standardised sampling to better understand snake fungal disease ecology and epidemiology in Italy.