Exposure To Rodents May Prevent Asthma And Allergies

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Main Category: Allergy
Also Included In: Respiratory / Asthma;  Immune System / Vaccines
Article Date: 03 Jul 2006 - 12:00 PDT

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People who regularly handle rodents in laboratories have fewer allergic reactions precisely because of their exposure, say researchers from Imperial College London, UK. It seems that exposure to some animals does have a protective effect. This is not the case for people who are exposed to non-animal allergens, such as bakers and people who work in detergent manufacturing plants.

Not all animals help reduce allergic reactions. Another study found that childhood exposure to dogs helped lower eczema risk, while childhood exposure to cats had the opposite effect.

You can read about the new study in the American Journal of Respiratory and Critical Care Medicine. The writers subscribe to the 'hygiene hypothesis' of allergies and asthma.

What is the Hygiene Hypothesis?

Put simply - it means that regular exposure to natural infections and microbes helps protect from the development of allergic diseases and asthma. In other words, rather than avoiding naturally occurring infections and microbes, exposure to them may be better.

As is the case with people who are regularly exposed to rodents in laboratories, they experience a natural form of immunotherapy.

Dr Meinir Jones, team leader, said "Interestingly, this does not seem to be the case for other groups at risk of occupational asthma such as bakers and detergent manufacturers." This may be because when one is regularly exposed to animals the contact is not only through inhalation, but through the skin as well when the animals scratch and bite.

The researchers looked at 689 volunteers - they all worked in science labs. They found that the lab assistants who had antibodies in their blood as a result of handling rodents were 50% less likely to experience chest symptoms as a result of their work, when compared to lab workers who did not have the specific antibodies. They also found that the more a lab assistant handled rodents, the more the rodent-specific antibodies were present.

It is also possible that those who handled the most rodents were also exposed to the highest number of microbes and dirt. This exposure may have helped them be more protected from allergies and asthma, say the researchers.

Written by: Christian Nordqvist
Editor: Medical News Today
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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