Background: Skeletal complication of brucellosis is common in endemic region of brucellosis, but its frequency has not been clearly determined. The aim of this study was to determine the frequency of skeletal complication in brucellosis patients in Babol, north of Iran.

Methods: From 2005-2015, 1252 cases of brucellosis were diagnosed at the Department of Infectious Diseases, Ayatollah Rouhani Teaching Hospital, in Babol, North of Iran. The diagnosis of brucellosis was established using serum agglutination test (SAT≥1/160), and 2-mercaptoethanol (2ME≥ 1/80) with clinical and epidemiological findings compatible with brucellosis. Among them, 464 (37.1%) cases demonstrated skeletal complication. The diagnosis of skeletal involvement was established with appropriate diagnostic facilities. The data were collected and analyzed.

Results: The mean age of these patients (299 males, 165 females) was 33.2±17.6 years. Three hundred-thirty four (72%) cases were from rural areas. In 350 (75.4%) patients with peripheral arthritis, 242 (52.1%) cases were monoarthritis. Furthermore the knee arthritis was seen in 148 (31.9%) patients and hip in 54 (11.6) cases. Sacroiliitis was seen in 59 (12.7%) patients and spondylitis in 55 (11.9%) cases. There were no significant differences regarding the occurrence of these focal lesions in both sexes.

Conclusion: The results show that about one-third of brucellosis in human is associated with skeletal complication. Peripheral arthritis, sacroiliitis and spondylitis are the frequent skeletal complications of human brucellosis.