- A distinct strain of Snake Fungal Disease (SFD) has been detected in snakes across Europe and Great Britain. SFD has caused population declines in US rattlesnakes.
- A wild grass snake was the first in Great Britain to be diagnosed with the disease in 2015, but more monitoring is needed to discover the effect on other native species.
- The Zoological Society of London’s Disease Risk Analysis and Health Surveillance for Interventions (DRAHS) Project works in partnership with Natural England and has developed guidelines for best practice risk management to reduce the spread of SFD and other infectious diseases of reptiles.
- Jenny Jaffe from the ZSL’s Institute of Zoology reports, and offers biosecurity advice for fieldworkers.
Snake Fungal Disease in the UK
Snake Fungal Disease (SFD) is an emerging infectious disease caused by the fungal pathogen Ophidiomyces ophiodiicola. Until recently SFD had only been recorded in snakes from North America (1), but a distinct strain has now been confirmed in wild snakes in Europe including Great Britain (2).
Detecting Snake fungal disease (SFD)
SFD was first detected in GB in 2015, in a wild grass snake (Natrix natrix) with a skin disease found in the East of England. The snake was lethargic, in poor body condition, and the scales on the underside of the body had small brown lesions with an irregular surface (see photo).
Further testing of grass snake carcasses and skin sheds with lesions has detected O. ophiodiicola from multiple locations across England. Continued monitoring is needed to determine if the other native snake species - European adder (Vipera berus) and smooth snake (Coronella austriaca) - are also susceptible to SFD.
Treatment & Control
Wildlife disease can cause effects at the population level (including extinctions) and ecosystem level. There are no effective measures known for the treatment or control of SFD in wild snakes. As such ecological consultants and herpetofauna workers should routinely use biosecurity protocols for reptile sites as they already do for amphibian sites. This can prevent SFD spreading from site to site, as well as other yet unknown reptile diseases.
It is vital to prevent humans from contributing to the spread of disease. ARG’s well-researched guide for UK Fieldworkers, ‘ARG UK Advice Note 4: Amphibian Disease Precautions: A Guide for UK Fieldworkers’(3) , highlights how to prevent the spread of diseases affecting amphibians, specifically chytrid fungus and ranavirus. However, there is less awareness regarding reptile disease precautions for UK field sites.
Reptile Biosecurity Protocols to Prevent Disease Spread
Reptile biosecurity protocols are similar to those for amphibians (3). The unboxing diseases.eu campaign has highlighted the risks of disease to amphibians and reptiles in Europe and provides downloadable images on biosafety for professionals (see below).
Guidelines for Consultants and Other Professionals
- Handle animals only when necessary
- Use a fresh pair of gloves for each site
- Clean and disinfect all equipment between sites, e.g storage buckets, boots, artificial refugia, cloth bags for handling
- Consider having two sets of field gear (so one can be disinfected while the other is in use)
- Use clean clothing or a clean overall over clothing between sites
- Release animals only at the place of capture
- Dedicated equipment should be used when working with wild reptiles and must never be shared between captive and wild reptiles
- Wild reptiles should not be brought into captivity where non-native reptiles are kept
- People keeping non-native reptiles are a higher risk if undertaking feildwork
- Park on the hard tarmac (rather than vegetated areas). Clean and disinfect tires if needed
- Report sick or dead amphibians and reptiles are seen in the wild to DRAHS@zsl.org and GWH@zsl.org
Guidelines for Cleaning & Disinfecting Hands & Equipment
- Wash clothing and cloth bags for handling reptiles at 40°C with biological detergent or at 60°C with non-bio detergent
- Equipment/ boots: scrub off soil and debris and soak in bleach solution or Virkon for at least 5 min, rinse with clean water and allow to dry
- Bleach - diluted to produce a 4% solution (Sodium hypochlorite is the active ingredient in household bleach, and concentrations vary between brands typically from 8-15%. It is important you check the concentration of the brand you are using, and adjust your dilution rate to arrive at 4%)
- Virkon - 10mg/ml, as per supplier’s instructions
The content for this blog has kindly been supplied by Jenny Jaffe.
Jenny Jaffe is from the Institute of Zoology’s Disease Risk Analysis and Health Surveillance for Interventions (DRAHS) Project, read more here.
The Zoological Society of London is an international conservation charity, devoted to the worldwide conservation of animals and their habitats since its was founded in 1826.
View the original poster on which this work is based, here.
(1) Lorch, J.M. et al. (2016) Snake fungal disease: an emerging threat to wild snakes. Philos. Trans. R. Soc. B 371, 20150457, doi:10.1098/rstb.2015.0457
(2) Franklinos, L.H.V., et al. (2017) Emerging fungal pathogen Ophiodiomyces ophiodiicola in wild European snakes. Scientific Reports doi:10.1038/s41598-017-03352-1 5) www.unboxingdisease.eu accessed 30 Jan 2018
(3) ARG UK (2017). ARG UK Advice Note 4: Amphibian Disease Precautions: A Guide for UK Fieldworkers. Amphibian and Reptile Groups of the United Kingdom.