The first diagnosis of Q fever in Wyoming livestock was made at the Wyoming State Veterinary Laboratory in January 2001, in several Boer goats from Crook County. The diagnosis was made based upon the history of numerous abortions, stillbirths, and births of weak kids in the herd, together with gross and microscopic lesions observed in the placentas of aborting animals. Placental lesions included necrosis and the presence of intracellular organisms within cells of the placenta, and the diagnosis was confirmed by immunohistochemistry for the causative agent of Q fever. Many of the goats were brought to Wyoming from Texas, a state where Q fever is fairly common in small ruminant species. Infection of ruminant species often is subclinical, but may be associated with late term abortions, stillbirths, or birth of weak offspring that may die.
Abortions typically occur during the first pregnancy, and are less common with ensuing pregnancies.
The organism may be shed in large numbers in placentas and fluids during abortion or delivery of offspring. Organisms also may be shed in milk from lactating females. Infection may occur by inhalation of contaminated dusts or other aerosols, by ingestion of raw milk or other products, or by tick or other arthropod bites. Some animals may shed organisms in placentas, fluids, and milk in subsequent pregnancies without aborting. The disease in people is associated with non-specific clinical signs resembling influenza.