PREVALENCE OF ANTIBODIES TO SPOTTED-FEVER GROUP RICKETTSIAE IN HUMAN-BEINGS AND DOGS FROM AN ENDEMIC AREA OF MEDITERRANEAN SPOTTED-FEVER INCATALONIA, SPAIN

We assessed the prevalence of antibodies to spotted fever group ricket tsiae in human beings and dogs by indirect immunofluorescence in the r egion of 'Valles Occidental', Barcelona (Spain). In the group of 150 s erum samples from patients without former history of Mediterranean spo tted fever, 12 had antibodies to Rickettsia conori. The overall seropr evalence was 8% (95% confidence interval, 4.6% to 13.5%). There were n o statistically significant differences between the mean ages of patie nts with positive and negative antibodies to R. conorii. However, sero positivity was significantly more common among patients living in semi -rural areas. In the group of 138 dog serum samples, 36 (26.1%) sera h ad antibodies to R. conorii. When the present results were compared wi th those obtained in a previous seroepidemiological survey carried out in the same geographical region in 1987, no significant differences w ere found. Therefore, although the epidemiological markers have droppe d, this does not absolutely confirm the decrease of the presence of R. conorii in this area.