TOXOPLASMA INFECTION AMONG PREGNANT-WOMEN IN SWITZERLAND - A CROSS-SECTIONAL EVALUATION OF REGIONAL AND AGE-SPECIFIC LIFETIME AVERAGE ANNUAL INCIDENCE

A simple generalized linear model of toxoplasmosis incidence has been applied to serologic data from more than 9,000 women who delivered bab ies in Switzerland. This model, based on an assumption of constant inc idence of toxoplasmosis throughout time and ages, yields estimates of incidence rates that show marked contrasts between subgroups of women categorized on the basis of their geographic origin and duration of re sidence in Switzerland. The patterns observed are in agreement with pr eviously reported data from specific areas. When applied to Swiss resi dent women of different age groups, the average incidence rate estimat es obtained were remarkably similar. This was not the case among the s ubgroup of Portuguese immigrant women, nor when the model was applied to previously published data from Sweden where toxoplasmosis incidence has clearly decreased in the last 20 years. Although models for the a nalysis of cross-sectional data involve major simplifying assumptions, it appears that they can yield useful epidemiologic information and t hat departures from the assumed simplified structure of the data can s ometimes be identified.