Familial Q fever clustering with variable manifestations imitating infectious and autoimmune disease.

Q fever, caused by Coxiella burnetii, can present as an outbreak of acute disease ranging from asymptomatic disease, pneumonia, hepatitis or fever of unknown origin, which can progress to a chronic disease, most frequently endocarditis. The occurrence of Q fever within families is rarely described, and in most cases presents with uniform acute disease manifestations. Here we present a familial cluster of Q fever presenting as highly variable synchronous manifestations in four of five family members, including prolonged fever of unknown origin, asymptomatic carrier state, hepatitis, and chronic endocarditis developing in the absence of previous symptoms. This case series highlights the possibility of Q fever developing in cohabitated individuals with highly variable symptoms masking the common disease etiology. Screening of all exposed individuals, even those not clinically suspected to be infected, may enable to better identify, treat and prevent progression to chronic disease.