Serologic Study of Bartonella henselae in Patients with Acute Undifferentiated Febrile Illness in Korea.

BACKGROUND: Bartonella infection is an emerging cause of acute febrile illness; however, its significance has not been thoroughly investigated. We studied the antibody specific to Bartonella henselae in patients with various febrile diseases in Korea. MATERIALS AND METHODS: A total of 177 patients with acute febrile illness who were managed at the Inha University Hospital from February 2012 to January 2013 were evaluated with an in-house immunofluorescent antibody test to detect B. henselae immunoglobulin G (IgG) antibody. The clinical features of the patients included fever of undetermined origin (n = 88 patients), lymphadenopathy (n = 28), febrile rash (n = 17), respiratory infection (n = 12), aseptic meningitis (n = 7), intra-abdominal infection (n = 5), arthritis (n = 4), and other conditions (n = 16). We reviewed the medical records of these patients and collected demographic data, clinical features, and their histories of animal exposure. RESULTS: Among the 177 patients with acute febrile illness, 23.7% (42/177) had elevated levels of IgG antibodies to B. henselae (≥1:160). Of these seropositive patients, 32.4% (12/37) had contact with animals and had developed arthralgia (29.5%), headache (25%), or lymphadenopathy (15.9%). Seven (16.7%) of the 42 patients had higher IgG titers (≥1:640). Among them, four patients presented fourfold increase/decrease of IgG in convalescent serum. According to the clinical diagnosis, the antibody positivity rates were as follows: 24/88 with undifferentiated fever, 8/28 with lymphadenopathy, 4/17 with febrile rash, 2/12 with respiratory infection, 2/7 with aseptic meningitis, and 2/16 with other illnesses. CONCLUSIONS: There was high prevalence of B. henselae in patients with undifferentiated fever in Korea, for which further research is needed.