Detection of antibodies to Bartonella henselae in clinically diagnosed cat scratch disease

Objective To determine the usefulness of an indirect immunofluorescence antibody test for antibodies to Bartonella henselae in diagnosing cat scratch disease (CSD). Design and setting Retrospective case survey of 354 patients whose sera were tested for antibodies to B. henselae at Royal Perth Hospital, Perth, and the Institute of Clinical Pathology and Medical Research, Sydney, in 1994; and measurement of the background prevalence of antibodies to B. henselae. Main outcome measures Prevalence of antibodies to B. henselae; odds of a positive titre (≥ 64) in patients with and without specific risk factors for CSD and clinical features of the disease; prevalence of antibodies to B. henselae in randomly selected blood donors. Results Demographic, clinical and cat contact data were available for 303 patients. Sixty‐four (21.1%) had a positive titre, as did 53 of 98 (54%) patients with a history of cat contact and lymphadenopathy. This proportion increased to 62% (38 of 61 patients) in patients with a history of cat scratch or bite and to 90.3% (28 of 31) in those with cat contact, lymphadenopathy and histological evidence of granulomatous lymphadenitis. Patients who developed lymphadenopathy after cat contact were significantly more likely to have a positive titre than those without this history (odds ratio [OR], 20.8; 95% confidence interval [95% CI], 9.6–46; P