Q fever in Gran Canaria: 40 new cases]

INTRODUCTION. The aim of this study was to describe the clinical and epidemiologic features of Q fever in the southern area of the island of Gran Canaria (Spain). METHODS. We conducted a retrospective analysis of the clinical and epidemiological data of the cases of Q fever diagnosed by the Microbiology Laboratory of the Hospital Universitario Insular in Gran Canaria between 1998 and 2000. Antibodies against phase II Coxiella burnetii antigens were detected using an indirect immunofluorescence test. The diagnosis of acute Q fever was established by IgG titers greater than or equal to 1:320 and IgM titers greater than or equal to 1:80, or by seroconversion. RESULTS. During the period of study 59 cases of acute Q fever were diagnosed, making an incidence of 5 cases/100,000 inhabitants/year. The seroprevalence (IgG greater than or equal to 1:80) in the patients for whom Q fever serology was requested during that period was 23.9%. Clinical and epidemiologic data were available for 40 patients. All were sporadic cases and 57% were hospitalized. The mean age of the patients was 40.6 +/- 13.3 years (range 20-74 years), 85% were males and 67.5% came from a rural background. The majority of cases (65%) clustered from April to July. The most frequent clinical presentation was an acute febrile process with elevated liver enzymes (87.5%). Pneumonia was infrequent (only three cases). CONCLUSIONS. In our area Q fever is mainly manifested as an acute febrile illness with subclinical hepatic involvement. This fact and the small number of cases with pneumonia and chronic forms suggest the etiological involvement of C. burnetii strains different from those in other geographic areas.