Ophidiomycosis in Wildlife: Causes, Clinical Signs, Diagnosis, and Management

Ophidiomycosis, also known as snake fungal disease (SFD), is a fungal infection that affects snakes and other reptiles. The disease was first identified in captive snakes in the 1990s and has since spread to wild populations across North America. SFD is caused by a fungus known as Ophidiomyces ophiodiicola, which can infect the skin, scales, and other tissues of snakes, causing lesions and other serious health problems. This article will explore the causes, clinical signs, diagnosis, and management of ophidiomycosis in wildlife.

Cause

Ophidiomycosis is caused by a fungus known as Ophidiomyces ophiodiicola, which belongs to the order Onygenales. The fungus can survive in the environment for long periods, and is believed to infect snakes through contact with contaminated surfaces or objects, such as soil, water, or other snakes. Ophidiomyces ophiodiicola is a slow-growing fungus that requires specific conditions to grow, including high humidity and temperatures between 20-30°C.

Significance

Ophidiomycosis is a significant threat to wild snake populations, particularly in North America, where it has been responsible for the decline and even local extinctions of some snake species. The disease is particularly concerning because it affects a wide range of snake species, including both venomous and non-venomous species. Ophidiomycosis also has the potential to spread to other reptiles, such as lizards, turtles, and crocodiles.

Species Affected

Ophidiomycosis has been reported in a wide range of snake species across North America, including several species of venomous snakes. Some of the most commonly affected species include eastern massasauga rattlesnakes, timber rattlesnakes, and copperheads. The disease has also been reported in non-venomous species, such as milk snakes, garter snakes, and water snakes.

Distribution

Ophidiomycosis has been reported in many parts of North America, including the eastern United States, the Midwest, and parts of Canada. The disease is most common in areas with high humidity and temperatures between 20-30°C, which are ideal conditions for the growth of Ophidiomyces ophiodiicola.

Transmission

Ophidiomycosis is believed to be transmitted through direct contact with contaminated surfaces or objects, such as soil, water, or other snakes. The fungus can also survive in the environment for long periods, and may be spread by other animals or through human activities, such as the transportation of infected snakes.

Clinical Signs

The clinical signs of ophidiomycosis can vary depending on the severity and location of the infection. Some of the most common signs include:

Lesions on the skin or scales, which may appear as crusty or scabby areas
Swelling or deformities in the head, eyes, or jaw
Difficulty shedding, leading to retained skin and a dull appearance
Loss of appetite and weight loss
Changes in behavior, such as increased lethargy or aggression
Respiratory problems, such as wheezing or abnormal breathing sounds

Diagnosis

Diagnosis of ophidiomycosis is based on a combination of clinical signs, laboratory tests, and imaging studies. A skin biopsy or culture may be taken to confirm the presence of Ophidiomyces ophiodiicola, and imaging studies such as radiography or ultrasound may be used to assess the extent of the infection.

Treatment

The treatment of ophidiomycosis or snake fungal disease is still a subject of ongoing research and development. Currently, there is no specific treatment that can eradicate the fungus completely. However, several treatments are available that can help reduce the severity of the disease and improve the survival rates of infected snakes.

One treatment option is the use of antifungal medications such as itraconazole and voriconazole. These drugs have shown promising results in some cases and are believed to work by inhibiting the growth and spread of the fungus. However, the use of antifungal drugs in wild snake populations is challenging due to difficulties in accurately diagnosing and treating individual snakes, as well as concerns about the impact of drugs on non-target species.

In addition to antifungal medication, supportive care can be provided to infected snakes. This can include wound care to prevent secondary bacterial infections, fluid therapy to maintain hydration, and nutritional support to aid in recovery. Infected snakes should also be housed in a clean, dry environment to reduce the risk of further fungal growth and transmission.

Preventative measures are crucial in managing ophidiomycosis. This can include maintaining proper habitat management, minimizing human disturbance of snake habitats, and avoiding the introduction of potentially infected snakes into new areas. Additionally, the proper sanitation of equipment used in the handling of snakes and the use of disinfectants can also help prevent the spread of the disease.

Overall, the management of ophidiomycosis is challenging and requires a multifaceted approach. Research is ongoing to develop more effective treatments and preventative measures to better manage this disease in wild snake populations.

Management

There is currently no known cure for Ophidiomycosis and treatment options are limited. The best course of action is to take preventative measures to minimize the spread of the disease.

One way to manage the disease is through habitat management. This includes removing infected snakes from the wild and decontaminating the area where the snake was found. It is important to keep infected snakes away from healthy populations, so monitoring and isolation of infected snakes is critical.

In captive environments, maintaining clean and dry housing for snakes can help prevent the spread of the disease. Quarantine and monitoring of new snakes before introducing them to a captive population is also important. Treatment of infected snakes in captivity involves the use of antifungal medications, but success rates vary.

Public awareness and education are also important aspects of managing Ophidiomycosis. The public can help reduce the spread of the disease by avoiding unnecessary handling of snakes and reporting sick or dead snakes to local authorities for further investigation.

Research is ongoing to find new treatment options and develop a better understanding of the disease. Continued monitoring and research will be critical in managing the spread of Ophidiomycosis and protecting snake populations from further decline.

Overall, management of Ophidiomycosis requires a multi-faceted approach that involves both habitat and captive management, public awareness and education, and ongoing research to better understand and treat the disease.

Conclusion

Ophidiomycosis, or snake fungal disease, is a serious threat to snake populations in North America. The disease is caused by a fungus that can cause a range of clinical signs, including skin lesions, swollen eyes, and overall lethargy. It is often fatal, particularly in species that are already at risk due to habitat loss and other threats.

Researchers are continuing to study the disease in order to better understand how it is spread and how it can be managed. However, at this time there is no known cure for the disease, making prevention and management strategies critical for protecting snake populations.

By practicing good hygiene when handling snakes, avoiding the movement of animals between populations, and monitoring snake populations for signs of infection, we can work to limit the spread of Ophidiomycosis and protect these important species for generations to come.

Sources

Lorch, J. M., et al. “Experimental infection of snakes with Ophidiomyces ophiodiicola causes pathological changes that typify the mycosis associated with snake fungal disease.” mBio 6.4 (2015): e01534-15.
Miller, D. L., et al. “Snake fungal disease: an emerging threat to wild snakes.” Philosophical Transactions of the Royal Society B 374.1782 (2019): 20190297.
Schloegel, L. M., et al. “The North American bullfrog as a reservoir for the spread of Batrachochytrium dendrobatidis in Ecuador.” Animal Conservation 10.3 (2007): 286-291.
Allender, M. C., et al. “Development and use of real-time quantitative PCR assays for detection of Batrachochytrium dendrobatidis chytridiomycosis fungus in amphibian samples.” Diseases of aquatic organisms 83.2 (2009): 89-99.
Schloegel, L. M., et al. “The pathogen Batrachochytrium dendrobatidis disturbs the frog skin microbiome during a natural epidemic and experimental infection.” Proceedings of the National Academy of Sciences 116.22 (2019): 10939-10948.