"RED-LEG"-AN INFECTIOUS DISEASE OF FROGS

Area of Science:

• Herpetology
• Veterinary Pathology
• Microbiology

Background:

• Frog "red-leg" disease, prevalent in North America and Europe, is a significant cause of amphibian mortality.
• The condition is observed primarily during warmer months, suggesting environmental factors play a role.

Purpose of the Study:

• To identify the causative agent of frog "red-leg" disease.
• To elucidate the clinical and pathological characteristics of the disease.
• To investigate potential predisposing factors and therapeutic interventions.

Main Methods:

• Isolation and pure culture of bacteria from diseased frogs.
• Inoculation of healthy frogs with the isolated bacillus to reproduce the disease.
• Clinical observation and post-mortem examination of diseased and inoculated frogs.
• Controlled experiments involving cold temperature exposure on infected frogs.

Main Results:

• Bacillus hydrophilus fuscus was consistently isolated from sick or deceased frogs and proven to be the causative agent through inoculation studies.
• The disease presents with ventral congestion, skin ulceration, hemorrhages, bloating, and systemic organ degeneration.
• Cold temperatures (near freezing) were found to significantly control disease symptoms and delay mortality in infected frogs.
• Anemia in frogs can be exacerbated by parasites like Distomum cylindraceum and bacterial action.

Conclusions:

• Bacillus hydrophilus fuscus is the etiological agent of "red-leg" disease in frogs.
• Skin lesions and weakened resistance due to heat and anemia are predisposing factors.
• Therapeutic application of cold temperatures offers a viable method for managing the disease in amphibians.