Published Online: September 19, 2015
Allergic diseases are becoming more common in many regions of the world, particularly in urbanizing populations. An idea to explain the increase in allergic diseases is the so-called hygiene hypothesis that suggests that a reduction in exposure to common infectious diseases of childhood may increase allergies. Further, the apparent low prevalence of allergies in rural parts of the tropics might be explained by protection against allergies provided by intestinal worms that are very common in populations living in the rural tropics. Maternal infections with these parasites during pregnancy may be particularly important in providing protection from early childhood but few studies have tested this idea.
In the article recently published in The Journal of Allergy & Clinical Immunology (JACI), Cooper and colleagues studied the effects of maternal infections with intestinal worms (also called geohelminths) on the development of allergies in a group of children from birth to 3 years of age in a rural District of Ecuador where intestinal worm infections are common. The authors measured worm infections during pregnancy and then followed up the children measuring wheezing illness, eczema, and skin sensitization to common allergens.
Maternal intestinal worm infections were common among mothers in the study, being detected during pregnancy in almost half of mothers. The authors did not observe a protective effect of maternal worms against the development of wheezing illness or eczema, and overall there was not a significant effect on sensitization to common allergens.
The authors concluded that the study did not provide evidence to support the idea that worm infections in mothers during pregnancy protect against allergies. However, the children have been followed up to 3 years of age to date and it is possible that studies of the children when they are older may be required to show a protective effect.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.