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Cat Scratch Fever/Cat Scratch Disease

Bartonella henselae (PDF), a newly described rickettsial organism, has been directly associated with cat scratch fever. This gram-negative, pleomorphic organism has been demonstrated to produce chronic, asymptomatic bacteremia, especially in younger cats, for at least 2 months, and possibly for as many as 17 months. The (PDF) has been isolated from fleas that fed on infected cats, and fleas have been shown to be capable of transmitting the organism between cats. This finding suggests that fleas could serve as a vector in zoonotic transmission. A recent prevalence survey indicated that approximately 49% of pet and pound/shelter animals have blood cultures.

Of patients with the disease, 75% report having been bitten or scratched by a cat, and over 90% report a history of exposure to a cat. Most cases of the disease appear between September and February, and the incidence peaks in December.

The disease begins with inoculation of the organism into the skin (bite or scratch) of an extremity, usually a hand or forearm. A small papule appears at the site of inoculation several days later, and is followed by vesicle and scab formation. The lesion resolves within a few days to a week.

Several weeks later, regional lymph node swelling occurs, and can persist for months. Suppuration and rupture of the lymph node sometimes occurs. Fever, malaise, anorexia, headache, and splenomegaly can also be present. Cat-scratch fever can progress to a severe systemic or recurrent infection that is life-threatening in immunocompromised hosts.

The use of proper cat-handling techniques, protective clothing, and thorough cleansing of wounds should minimize the likelihood of personnel exposure to the organism of cat-scratch fever. Flea control measures should also be implemented.