On the epidemiology of human toxoplasmosis in Scandinavia especially in children.

A random sample representing approx. one-third of pre-school children and approx. 95% of school children in age groups 8, 11, 13, and 15 years in a suburb of Stockholm were examined for antibodies to Toxoplasma. Antibodies were uncommon in small children. They gradually appeared throughout childhood but especially in adolescence and adult life. Antibodies were more common in females than in males. Even small girls were more often infected than boys of corresponding age. The difference becomes marked in puberty and is significant in adults. A family study revealed evidence of familial aggregation of the infection albeit with borderline significance. No correlation was found between occurrence of antibodies and the presence of cats in the families or reported consumption of raw meat. The majority of representative samples of Lapps and Skolt Lapps in northern Scandinavia lacked antibodies to Toxoplasma.