Q fever in The Netherlands. A report of 33 cases observed between 1979 and 1983

The number of cases of Q fever diagnosed in The Netherlands has been on the increase since 1980. A study was made of the clinical symptoms of 33 patients in whom the diagnosis was confirmed serologically. In addition an epidemiological investigation was carried out. Apart from general symptoms, 18 of them (54%) presented pneumonia, 2 (6%) showed clinically manifest hepatitis and 3 (9%) had endocarditis. Optic neuritis was observed in 1 patient. The indirect immunofluorescence test on IgM antibodies against C. burnetii proved to be more sensitive than the complement fixation test. On epidemiological grounds, the source of the infection had to be localized in The Netherlands in 22 cases (67%). Q fever is no longer rare in the The Netherlands. The possibility should be considered in all patients with fever of unknown origin. The diagnosis is made on the basis of laboratory findings.