Dermatophilosis, also called streptothricosis (cattle), rain scald, rain rot, grease heal (horses), lumpy wool and strawberry footrot (sheep), is a skin infection caused by actinomycete Dermatophilus congolensis usually as a result of penetrating wounds contaminated by infected soil or water. Dermatophilus species are gram-positive, branching, filamentous rod-shaped bacteria that are obligate parasites. Cattle, sheep and horses are common hosts, however, dermatophilosis has also been diagnosed in goats, swine, dogs, cats, turkeys, humans and wild mammals, including marine mammals.1
Spread of the bacteria is by direct physical contact of animals or indirect contacts via ticks and other arthropods. Transmission is facilitated in moist conditions. The disease is characterized by the formation of crusts and a tendency to spread over large areas of the body. When the crusts are pulled off, the underlying skin is red and ulcerated and usually contains a green to yellow mass of cells and fluid. Diagnosis is made by direct smear or histopathologic examination. In temperate climates dermatophilosis is often a mild infection and uncomplicated infection usually heals without scar formation. In tropical countries it may be a cause of a severe, often fatal disease.2
In affected cats, deeper abscesses in muscle, lymph nodes and subcutaneous tissues have been often seen. The abscesses may produce chronic draining cavities. Fever, loss of appetite, enlarged lymph nodes are common. Ulcerative granulomas of the tongue and urinary bladder often develop. The bacteria is susceptible to penicillin and tetracycline. Ampicillin and amoxicillin have been administered to cats successfully to treat cats with abscesses.3
- Veterinary Microbiology. D. Scott McVey, Melissa Kennedy, M. M. Chengappa
- Diagnostic Procedure in Veterinary Bacteriology and Mycology. Grace R. Carter, John R. Cole, Jr.
- Infectious Diseases of the Dog and Cat. Craig E. Greene
- Ixodid ticks of traditionally managed cattle in central Nigeria: where Rhipicephalus (Boophilus) microplus does not dare