ROCHALIMAEA-HENSELAE INFECTION - A NEW ZOONOSIS WITH THE DOMESTIC CATAS A RESERVOIR

Objective.-To determine the reservoir and vector(s) for Rochalimaea he nselae, a causative agent of bacillary angiomatosis (BA) and cat scrat ch disease, and to estimate the percentage of domestic cats with R hen selae bacteremia in the Greater San Francisco Bay Region of Northern C alifornia. Design.-Hospital-based survey of patients diagnosed with BA who also had significant exposure to at least one pet cat, as well as a convenience sampling of pet or impounded cats for prevalence of Roc halimaea bacteremia. Setting.-Community and university hospitals and c linics; veterinary clinics treating privately owned or impounded cats. Patients.-Patients with or without human immunodeficiency virus infec tion, with biopsy-confirmed BA, who had prolonged exposure to pet cats prior to developing BA. Main Outcome Measures.-Cultures and laborator y studies were performed on blood drawn from pet cats associated with patients with BA. The Rochalimaea species infecting pet cats and fleas and causing the BA lesions in human contacts of these cats was identi fied by culture, polymerase chain reaction-restriction fragment length polymorphism analysis, and DNA sequencing. The presence of R henselae bacteremia in pet cats was documented, and predictor variables for cu lture positivity were evaluated. Results.-Four patients diagnosed with BA who had prolonged contact with seven pet cats were identified. The Rochalimaea species causing BA lesions in these patients was determin ed to be R henselae. The seven pet cats were found to be bacteremic wi th R henselae; this bacterium was also detected in fleas taken from an infected cat by both direct culture and polymerase chain reaction. Bl ood samples were cultured from pet and impounded cats (N=61) in the Gr eater San Francisco Bay Region, and Rhenselae was isolated from 41% (2 5/61) of these cats. Conclusion.-We have documented that the domestic cat serves as a major persistent reservoir for R henselae, with prolon ged, asymptomatic bacteremia from which humans, especially the immunoc ompromised, may acquire potentially serious infections. Antibiotic tre atment of infected cats and control of flea infestation are potential strategies for decreasing human exposure to R henselae.