The rate of increase in prevalence of allergic disease in some countries implies environmental exposures may be important etiological factors.21 studies were included in this systematic review.
Current parasite infection was associated with a reduced risk of allergen skin sensitization (odds ratio [OR] 0.69). When analyses were restricted to current geohelminth infection, the size of effect remained similar, OR 0.68.
In species-specific analysis, a consistent protective effect was found for infection with:
- Ascaris lumbricoides
- Tricuris trichuria- hookworm
- Schistosomiasis
Intestinal parasite infection appears to protect against allergic sensitization. Harnessing these in a safe way may reduce the global burden of allergic disease.
However a recent Cochrane review did not find benefit in their meta-analysis of previous studies: No evidence for use of helminths (worms) as routine treatment for allergic rhinitis - nice wording from Cochrane http://goo.gl/cWlKd
Colonoscopy Video Demonstrating a Moving Worm (NEJM).
References:
Feary J, Britton J, Leonardi-Bee J. Atopy and current intestinal parasite infection: a systematic review and meta-analysis. Allergy 2010; DOI: 10.1111/j.1398-9995.2010.02512.x00: 00–00.
Image source: Trichuris egg in stool sample (40x). Wikipedia, GNU Free Documentation License, Version 1.2.
Comments from Twitter:
@AllergyNet: My thoughts on where this may lead bit.ly/oS3F3S
@kfatweets: I think I will skip watching the video of the moving worm. :)
AllergyMentor @AllergyMentor: Discussed at FAAN conf today