Faculty of Medicine

Intestinal Worms may Solve Allergy Puzzle

While young people with parasite worms currently have a four times higher risk for developing allergies and asthma than others. Their parents are generally unaffected.

Intestinal worm
INTESTINAL WORMS: Helminths ( Toxocara Canis) are associated with allergies in young people.

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Researchers at Centre for International Health (CIH) at the University of Bergen (UiB) were surprised when they found that intestinal worms, so-called Helminths (Toxocara Canis) from animals, actually have an influence on allergy- and asthma risk in humans.

Their results showed that young people who test positive for this parasite, have a 4 times higher risk of developing asthma and allergies than others.

“Usually, we consider a 50 per cent higher risk as being high, but here we see a 400 per cent higher risk,” says Professor Cecilie Svanes at CIH, Department of Global Public Health and Primary Care, UiB.

According to Svanes, what is interesting in these results is that it seems to be only the young generation who has higher risk of getting asthma and allergies if they test positive on helminths, and not their parents.

“We do not know why the parasite only influences the young generation in a negative way and not their parents. If we can discover the reason for this, I think we will have solved the puzzle of why allergies have  increased enormously over the past few decades,” says Svanes.

The study is published in Clinical & Experimental Allergy.

Allergy explosion

Many studies show that the numbers of people with asthma and allergies have increased enormously over the past few decades. The reason for this is unknown.

“One of the most common hypotheses is that we have become more in contact with chemicals and less in contact with microbes and bacteria,” Svanes explains.

“There are, however, many things that have changed during the last decades. Nobody knows why allergy and asthma levels have increased. The phenomena is happening all over the world. It probably relates to urbanisation among other things.”

Applying for an EU Grant

Svanes´ study is financed by Worldwide Universities Network (WUN), where UiB is a member institution. She has now applied for an ERC Advanced Grant at the European Research Council (ERC) to support further research on the parasitic worms. If she is successful, she plans to study the helminths in more age groups in different countries. Other things she would like to consider include studying genetic changes as a possible consequence of the parasites as well as that different worm species may have immune stimulating or damaging effects.

“Parasitic worms may influence the immune system in either positive or negative ways. This could be exploited for the possible treatment and prevention of allergies. The current project, however, is focused on the mechanisms behind the allergy increase over the last decades,” Cecilie Svanes says.