Fungal Disease in Amphibians

Chytridiomycosis

Chytridiomycosis is a serious infectious disease caused by Batrachochytrium dendrobatidis, a zoosporic fungus related to water molds. The fungus feeds on keratin, a protein found in the outermost layers of the skin, and survives in most environments, even without a host. It is believed that the decrease in the population of frogs in many areas is due to chytridiomycosis.

A common way to recognize chytridiomycosis is to check your amphibian's skin for sloughing or shedding. The disease can be fatal for amphibians left untreated. Therefore, owners suspecting chytridiomycosis in their amphibian must seek immediate veterinary care.

Symptoms and Types

An amphibian suffering from chytridiomycosis may shed excessively, develop thickened or pale skin and, in the cases of tadpoles, disfigured beaks. Other common symptoms or signs include:

• Lethargy
• Loss of appetite (anorexia)
• Constriction of the eye's pupil
• Abnormal posture of the hind legs
• Abnormal behavior and disposition
• Hyperemia (an increase in blood flow to different body tissues)

Some amphibians present no clinical symptoms of the disease, but are still infected with the Batrachochytrium dendrobatidis fungus. These animals are carriers of the disease.

Causes

Chytridiomycosis is due to an infection with the B. dendrobatidis fungus. Generally, amphibians contract the fungus through their skin while in contaminated water.

Diagnosis

Veterinarians diagnose the disease by examining skin scrapings or toe clips that are stained and put under a light microscope. Placing an infected animal in a shallow dish of water will often confirm the sloughing of skin, a common symptom for chytridiomycosis.

Treatment

To treat chytridiomycosis, your veterinarian will prescribe antifungal medication, such as itraconazol, which is usually diluted and administered as a bath. Supplemental treatment may include ultraviolet light therapy.

Living and Management

For unknown reasons, chytrid infections have a high mortality rate. Therefore, it is important you follow your veterinarian's instructions and provide a clean aquatic environment and an appropriate temperature range for your amphibian.