The Role of Dairy Cattle in the Epidemiology of Q Fever in Idaho

In 2 study areas in Idaho, the incidence of antibodies against Coxiella burnetii and of disabling febrile illnesses of 2 days or more duration among families associated with 119 infected herds of dairy cattle was compared with findings among families associated with 141 Q fever-free herds. Twenty-six per cent of 333 persons in the former group were seropositive, whereas only 14% of 394 persons in the latter group were seropositive. The data showed that dairy cattle were a source of infection for man but that a significant amount of clinical illness was not associated with these infections.