Sheep-associated outbreak of Q fever, Idaho.

Between Feb 1 and Aug 31, 1984, an outbreak of 18 symptomatic cases of Q fever occurred in Idaho; these numbers represent an increase over the three cases reported in 1982 and the five reported in 1983. Four of the patients in the outbreak required hospitalization for two to five weeks; there were no fatalities. Eight of the cases had documented Q fever hepatitis, and one had pneumonia. All 18 of the 1984 cases for whom information was available were epidemiologically linked to visiting or working at a sheep research station and/or being exposed to animals from this research station. In this outbreak, patients typically had a hepatitislike illness associated with fever and severe headache. Severity of illness ranged from asymptomatic to life threatening. Cases of pneumonia and hepatitis due to Q fever continue to occur in the United States, especially among persons exposed to livestock.