Seasonal trends in acute toxoplasmosis in pregnancy in the federal state of Upper Austria.

Knowledge about seasonal trends in acute toxoplasmosis in pregnancy may help to understand and avoid risk factors for infection. Analysing regular screening records of 51 754 pregnant women, members of the largest statutory health insurance company in the federal state of Upper Austria from 2000 to 2005, we found a twofold increase of diagnoses of acute toxoplasmosis during winter months. Taking the delay between infection and screening into account, the increased number of detections in winter points towards more frequent infections in autumn. We propose a higher consumption of contaminated vegetables and fruit from gardening as one of the potential explanations.