An epidemiological and serological study of toxocara infection in Sweden

The serological prevalence of toxocara infection was determined in 323 sera from statistically selected healthy individuals from different geographical areas of Sweden. The serological response in 175 sera from patients suspected of having contracted toxocariasis was compared with their clinical manifestation and age. The sera were analysed by ELISA using excretory/secretory antigens. The serological prevalence in young adults was estimated to 7%, indicating that subclinical toxocariasis occurs in healthy Swedes. The prevalence figure is not contrasting with reports from other countries. Antibodies were predominantly demonstrated in sera from men living in a rural community compared to sera from the other areas investigated (p less than 0.01). 91% of the sera from patients were obtained from patients greater than 5 years old. The clinical manifestations were ocular disorder (46%), eosinophilia (32%), lung, liver, neurological disorders (14%). The disorders were equally distributed between the age groups. A seropositive reaction was noted in 25% of the patients and the various clinical manifestations and age groups were equally represented among the seropositives. However, the percentage of seropositive patients with ocular disorders increased with growing age, whereas the opposite was observed in patients with eosinophilia. The results indicate that clinically apparent toxocariasis exists in Sweden.