A case of Q fever in a sheep producer was detected by a surveillance system in North Dakota in 1993, when Q fever was not reportable. This is the first officially documented case in the state. To estimate the prevalence of Coxiella burnetii infection and identify associated risk factors, we conducted a study covering the whole state. A total of 17 cases were identified among 496 sheep producers, their family members, and hired helpers. The number of sheep raised was a good predictor of C. burnetii infection. Lambing outdoors and frequent physical contacts with sheep during lambing were associated with a higher risk, but petting dogs was correlated with a lower risk. We conclude that C. burnetii infection is prevalent among sheep producers in North Dakota. As the result, Q fever became a reportable disease in North Dakota.
From the Division of Surveillance, Hazard Evaluation and Field Studies, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio (Dr Guo, Dr Freund); the Department of Environmental and Occupational Health, National Cheng Kung University, Tainan, Taiwan, R.O.C. (Dr Guo); the North Dakota State Department of Health and Consolidated Laboratories, Bismarck, ND (Mr Gilmore); and the U.S. Army Medical Research Institute for Infectious Disease, Frederick, Md. (Dr Waag).
Address correspondence to: How-Ran Guo, MD, ScD, Department of Environmental and Occupational Health, National Cheng Kung University Medical College, 138 Sheng-Li Road, Tainan 70428, Taiwan, R.O.C.