But nature works in mysterious ways, even where the seemingly lowly hookworm is concerned. Check out the following press release, issued today by the University of Nottingham:
A study conducted in Vietnam has added further weight to the view
that parasitic gut worms, such as hookworm, could help in the
prevention and treatment of asthma and other allergies.
Led by
Dr Carsten Flohr, a Clinical Scientist from The University of
Nottingham, and Dr Luc Nguyen Tuyen from the Khanh Hoa Provincial
Health Service in central Vietnam, the study is the largest
double-blind placebo controlled clinical trial to date looking at the
potential links between hookworm and other gut worm infections and
allergic conditions such as asthma and eczema.
(Image: CDC)
Thanks to
improved hygiene practices parasitic worms have been mostly eradicated
among human populations living in developed countries. However, experts
believe that over millions of years of co-evolution worms have found
methods to dampen down host immune responses to prolong their own
survival inside humans. This relationship seems to have become so
intertwined that without gut worms or other parasites, our immune
system can become unbalanced, which in turn could contribute to the
development of asthma and other allergies. At the same time, it is
important to remember that gut parasites can cause severe disease and
are a major cause of iron-deficiency anaemia in developing countries.
Dr
Flohr’s study was conducted in a rural area of central Vietnam where
two out of three children have hookworm and other gut parasite
infections and where allergies are extremely rare. More than 1,500
schoolchildren aged 6-17 took part.
The team investigated
whether repeated tablet treatments to clear the body of gut worms made
it more likely for children to develop allergic conditions. While the
treatment did not demonstrate an effect on asthma or eczema, the
treated children had a significantly increased risk of having a
positive allergy skin test to house-dust mites and cockroach. This
suggests that gut worms have the potential to tone down human immune
responses and so further research is now needed to identify precisely
how gut worm infection can prevent allergic sensitisation.
Dr
Carsten Flohr of The University of Nottingham adds: “The next step is
to understand exactly how and when gut parasites programme the human
immune system in a way that protects against allergic sensitisation,
and for such studies, follow-up from birth will be essential.”
As
up to 80 per cent of people with asthma also have allergies to
house-dust mites and other environmental allergens, additional research
in this area could aid the creation of new treatments that work in the
same way as gut parasites, by dampening down or rebalancing the immune
system so that the body does not respond to allergens and trigger
asthma attacks.
Dr Elaine Vickers, Research Relations Manager at
Asthma UK, says: “Asthma affects more than five million people in the
UK, with a person being admitted to hospital every seven minutes
following an asthma attack. The prospects of further studies in this
area are therefore very exciting as we could see groundbreaking
treatments for asthma and other allergies developed as a result. It’s
now vital that we see more funding being invested in this important
area of research, so that we can increase our understanding of the link
between gut parasites and the development of allergies from birth.”
Co-applicants
on the Asthma UK research grant that funded the work were Professors
John Britton, David Pritchard, and Hywel Williams. The Nottingham team
collaborated with researchers from the Wellcome Trust Major Overseas
Programme at the Oxford University Clinical Research Unit Hospital for
Tropical Diseases in Ho Chi Minh City, where Dr Flohr was based for his
work. Additional funding was received through the Bastow Award from the
Special Trustees for Nottingham University Hospitals. Dr Flohr’s salary
was provided by University College, University of Oxford, for two years
and by the Wellcome Trust UK for a further nine months.
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