Harriet Mpairwe, first author of the new study, says: "Worm infections can adversely affect a person's health, but the evidence also suggests that exposure to infection early in a child's life can have a beneficial effect in terms of modifying its immune system and protecting against allergies. We wanted to examine in a large cohort what effect de-worming women during pregnancy has on their offspring."
The researchers showed for the first time that treatment of pregnant women with albendazole appeared to almost double the risk of eczema in their offspring (an increase by a factor of 1.8) and that treatment with praziquantel more than doubled (an increase by a factor of 2.6) the risk of eczema among infants of mothers infected by the Schistosoma mansoni worm (a parasite which causes the disease schistosomiasis).
The findings support the hypothesis that maternal worms during pregnancy, neonatal life and early breastfeeding, may protect against allergy in infancy and that treatment of these worms during pregnancy increases the risk of allergy.
Professor Alison Elliott from the London School of Hygiene and Tropical Medicine, senior author of the study, says: "Our study suggests that routine de-worming during pregnancy, in settings where most worm infections are mild, may not be beneficial for the children and may actually cause problems with allergy. However, before we recommend changes to treatment policy, we need to do more work to confirm these findings and better understand what is happening.
"The findings certainly support the so-called 'hygiene hypothesis'. What will be important for the eczema story will be to see whether there are long term effects on allergy, especially asthma, at school age. Our next step is to investigate this further."
|Contact: Craig Brierley|