WARC researchers used visual encounter surveys to determine prevalence rates of snake fungal disease in south-central Louisiana.
The Science Issue and Relevance: In the last 20 years, an extraordinary number of fungal and fungal-like diseases have caused some of the most severe die-offs and extinctions ever observed in wild species. Snake fungal disease (SFD) is a recently documented mycotic disease that has been deemed a global conservation issue and an emerging threat to wild snake. Snake fungal disease became more widely known after two 2011 publications documented high mortality rates caused by SFD in two protected species of pit viper in the Midwestern and Northeastern United States. We confirmed SFD in Louisiana in 2015, but virtually nothing is known about prevalence rates or populations impacts of SFD in the Southeastern United States.
Methodology for Addressing the Issue: We use visual encounter surveys to sample snakes in a capture-mark-recapture (CMR) approach in a small area (~ 3 ha) of semi-permanent and ephemeral wetlands at Palmetto Island State Park in Louisiana. This site was chosen due to the presence of snakes with clinical signs of SFD and the thought that snakes, notoriously hard to recapture, may be recaptured here with some success. After sexing and taking standard measurements of captured snakes, each snake is marked by injection of a passive integrated transponder (PIT) tag and then marked for future identification. After diagramming all areas of possible dermatitis, we take 1-4 swabs of each snake dependent upon the severity of clinical signs of SFD. All areas swabbed are also photographed. We use a real-time polymerase chain reaction (qPCR) assay to detect O. ophiodiicola, the causative agent of SFD, on our swab samples. Marking, swabbing, and photographing each capture allows us to determine prevalence rates by species, and investigate disease progression and its possible effects on fitness and survival. Multi-state CMR models are used to estimate survival of infected and uninfected snakes as well as the probability of an individual transitioning from one state to the other.
Future Steps: We suspended sampling at Palmetto Island State Park in early 2019. We are working to put together the results in anticipation of one or more publications.
Below are publications associated with this project.
Low-level detection of SFD-causing Ophidiomyces on Burmese Pythons in southwest Florida, with confirmation of the pathogen on co-occurring native snakes
Snake fungal disease: An emerging threat to wild snakes
First documented case of snake fungal disease in a free-ranging wild snake in Louisiana
- Overview
WARC researchers used visual encounter surveys to determine prevalence rates of snake fungal disease in south-central Louisiana.
The Science Issue and Relevance: In the last 20 years, an extraordinary number of fungal and fungal-like diseases have caused some of the most severe die-offs and extinctions ever observed in wild species. Snake fungal disease (SFD) is a recently documented mycotic disease that has been deemed a global conservation issue and an emerging threat to wild snake. Snake fungal disease became more widely known after two 2011 publications documented high mortality rates caused by SFD in two protected species of pit viper in the Midwestern and Northeastern United States. We confirmed SFD in Louisiana in 2015, but virtually nothing is known about prevalence rates or populations impacts of SFD in the Southeastern United States.
A young broad-banded watersnake from south-central Louisiana confirmed to have snake fungal disease Methodology for Addressing the Issue: We use visual encounter surveys to sample snakes in a capture-mark-recapture (CMR) approach in a small area (~ 3 ha) of semi-permanent and ephemeral wetlands at Palmetto Island State Park in Louisiana. This site was chosen due to the presence of snakes with clinical signs of SFD and the thought that snakes, notoriously hard to recapture, may be recaptured here with some success. After sexing and taking standard measurements of captured snakes, each snake is marked by injection of a passive integrated transponder (PIT) tag and then marked for future identification. After diagramming all areas of possible dermatitis, we take 1-4 swabs of each snake dependent upon the severity of clinical signs of SFD. All areas swabbed are also photographed. We use a real-time polymerase chain reaction (qPCR) assay to detect O. ophiodiicola, the causative agent of SFD, on our swab samples. Marking, swabbing, and photographing each capture allows us to determine prevalence rates by species, and investigate disease progression and its possible effects on fitness and survival. Multi-state CMR models are used to estimate survival of infected and uninfected snakes as well as the probability of an individual transitioning from one state to the other.
Future Steps: We suspended sampling at Palmetto Island State Park in early 2019. We are working to put together the results in anticipation of one or more publications.
- Publications
Below are publications associated with this project.
Low-level detection of SFD-causing Ophidiomyces on Burmese Pythons in southwest Florida, with confirmation of the pathogen on co-occurring native snakes
Snake fungal disease (SFD), or ophidiomycosis, is caused by the fungus Ophidiomyces ophiodiicola (Allender et al. 2015; Lorch et al. 2015). SFD is widespread across wild populations in the eastern United States (Lorch et al. 2016) and is known to infect more than 30 species of snake in North America and Europe (Lorch et al. 2016; Franklinos et al. 2017). No known phylogenetic or ecological patternAuthorsBrad Glorioso, Ian A. Bartoszek, Jeffrey M. LorchSnake fungal disease: An emerging threat to wild snakes
Since 2006, there has been a marked increase in the number of reports of severe and often fatal fungal skin infections in wild snakes in the eastern USA. The emerging condition, referred to as snake fungal disease (SFD), was initially documented in rattlesnakes, where the infections were believed to pose a risk to the viability of affected populations. The disease is caused byOphidiomyces ophiodiiAuthorsJeffrey M. Lorch, Susan Knowles, Julia S. Lankton, Kathy Michell, Jaime L. Edwards, Joshua M. Kapfer, Richard A. Staffen, Erik R. Wild, Katie Z. Schmidt, Anne Ballmann, Doug Blodgett, Terence M. Farrell, Brad M. Glorioso, Lisa A. Last, Steven J. Price, Krysten L. Schuler, Christopher Smith, James F. X. Wellehan, David S. BlehertFirst documented case of snake fungal disease in a free-ranging wild snake in Louisiana
Snake fungal disease (SFD) is a recently documented mycotic disease characterized by scabs or crusty scales, subcutaneous nodules, abnormal molting, cloudiness of the eyes (not associated with molting), and localized thickening or crusting of the skin. SFD has been documented in many species in the Eastern and Midwestern United States within the last decade. SFD has proven lethal in many snakes, aAuthorsBrad M. Glorioso, J. Hardin Waddle, David E. Green, Jeffrey M. Lorch