Epizootic podoknemidokoptiasis in American robins

Area of Science:

• Veterinary Parasitology
• Avian Pathology
• Wildlife Disease Ecology

Background:

• Scaly leg disease in birds is often caused by mites.
• The mite Knemidokoptes jamaicensis is a known avian pathogen.
• Migratory birds can serve as vectors for disease transmission.

Purpose of the Study:

• To document epizootics of scaly leg disease in American robins.
• To identify the causative agent, Knemidokoptes jamaicensis, in North American robin populations.
• To describe the clinical and histological presentation of the disease.

Main Methods:

• Field observations and sample collection from migratory American robins in Tulsa, Oklahoma.
• Histopathological examination of affected avian tissues.
• Incidental case confirmation in robins from Georgia and Florida.

Main Results:

• Epizootics of scaly leg disease caused by K. jamaicensis occurred in American robins during 1993-95 in Oklahoma.
• Infection rates ranged from 60% to over 80% in arriving migratory flocks.
• Lesions varied from hyperkeratosis to severe proliferative changes and digit loss.
• Histology revealed hyperkeratosis, mites, and inflammatory responses.

Conclusions:

• This is the first confirmed report of K. jamaicensis epizootics in North American robins.
• The efficacy of ivermectin for treating knemidokoptic mange in robins is questionable.
• Captivity may increase mite transmission rates and disease severity in birds.