Hookworms may prevent asthma

Asthma is less common in rural areas in Africa than in towns. In this week’s issue of The Lancet, Prof John Britton and colleagues report results from a study carried out in Jimma, Ethiopia. 9844 people living in towns and 3032 people living in the country were involved. The researchers asked the participants whether they wheezed or not over the previous 12 months and took samples of their faeces to test for hookworm.

Those people whose faecal samples tested positive for hookworm were half as likely to have asthma as those who tested negative for hookworm. The authors suggest that hookworms in the intestine may alter the way the body reacts to the factors that may provoke asthma.

The authors state, “ This finding supports the notion that the local immune suppression by parasites that has probably evolved to facilitate the passage of the parasite through host tissues might also suppress local inflammatory responses to allergens.”

Contact Prof John Britton, Division of Respiratory Medicine, University of Nottingham, Nottingham NG5 1PB, UK. E) [email protected].