Seroprevalence of Toxoplasma gondii in Sweden, Estonia and Iceland.

Toxoplasmosis is a disease caused by the intracellular protozoan parasite, Toxoplasma gondii which infects up to one-third of the world human population. Toxoplasmosis in neonates and immunocompromised patients can lead to severe disease and death. We investigated the prevalence and risk factors for T. gondii infection in Iceland, Sweden and Estonia, and tested the hypothesis that T. gondii infection causes systemic inflammation and protects against atopy. Blood samples were collected from 1277 randomly selected subjects. The presence of T. gondii IgG antibodies was determined by an ELISA method and levels of Hs-CRP by immunoturbidimetric assay. The prevalence of T. gondii antibodies was 54.9% in Tartu, 23% in Uppsala and 9.8% in Reykjavik (p<0.0001). The risk of positive T. gondii antibodies increased with the number of siblings and with age in Sweden. T. gondii infection was associated with asthma related symptoms and increased Hs-CRP (p = 0.02). No association was found with IgE-sensitization and lung function. We concluded that risk factors for T. gondii infection suggested that soil exposure was 1 of the mechanisms in all 3 countries and a meat-associated infection route is a risk in Sweden.

[Foodborne infections in Iceland. Relationship to allergy and lung function]. / Algengi IgG mótefna gegn Toxoplasma gondii, Helicobacter pylori og lifrarbólguveiru A á Islandi. Tengsl vieth ofnaemi og lungnaeinkenni.

BACKGROUND: Foodborne or orofecal transmitted infections can have influence on health by direct consequences of the infection and indirectly by modulating the immune system. OBJECTIVES: To investigate the prevalence and risk factors for T. gondii, H. pylori and HAV infection in the Icelandic population and their influence on atopy, allergy related lung symptoms and lung function. MATERIAL AND METHODS: Blood samples were collected in 1999-2001 from 505 subjects in age group 28-52, randomly selected from the Icelandic population. The presence of T. gondii, H. pylori and HAV IgG antibodies was determined by an ELISA method. Allergy related lung symptoms were assessed with questionnaire and IgE sensitization and lung function measured. X(2) test was used to test for trend but unadjusted logistic regression for comparison of IgG prevalence. Multiple logistic regression was used to calculate adjusted odds ratios and 95% confidence intervals for different infections factors. RESULTS: The prevalence of antibodies was 9.8%, for T. gondii, 36.3% for H. pylori and 4.9% for HAV. Attending day care before the age of 3 years was a risk factor for having T. gondii antibodies. The prevalence of H. pylori increased with age and smoking. The infections were not associated with the prevalence of asthma or atopy. Having IgG antibodies against T. gondii was, however, associated with an increased risk of having FEV/FVC ratio below 70%. CONCLUSION: T. gondii, H. pylori and H AV infection does not influence the prevalence of atopy or asthma. The data indicated that infection with T. gondii might be associated with a diminished lung function.