Direct transmission of Q fever between persons who have been exposed t
o Coxiella burnetii and their family members has been hypothesized cin
the basis of the results of serological surveillance. We studied nine
shepherds who were employed in Spain during the sheep shearing season
, After they returned to Poland, Q fever was detected in these shepher
ds and their wives. The titers of serum antibodies to phase I C. burne
tii antigens ranged from 0 to 64 in patients with Q fever and in their
spouses, and the titer of serum antibodies to phase II antigens range
d from 0 to 1,024 in patients and their spouses, Other family members
were seronegative for antibodies to C. burnetii. C. burnetii strains w
ere isolated from urine and semen samples obtained from patients with
Q fever, Attached bacteria have been detected in spermatozoal cells ob
served with use of scanning electron microscopy.