Obesity could be contagious
Obesity could be caused by a virus in some people, says a study published in last month's International Journal of Obesity (2000; 24: 989-96).
Human adenovirus-36 (Ad-36) may be responsible for fat accumulation in up to 30% of obese people. In the study, obese individuals with these viral antibodies also had lower cholesterol and triglyceride levels.
Dr Nikhil Dhuranda is one of
the doctors behind the research.
He originally injected mice and
chickens with Ad-36 and found
that 60-70% of the animals
became clinically obese. On
screening 500 people in the
United States, he discovered that
30% of obese individuals carried
the antibodies.
A virus may be responsible for obesity in up to 30% of people(CORCIOLANI/VOLLER ERNST/S.O.A PHOTO AGENCY)
"This is the first time a human
virus has been associated with
obesity," says Dhuranda. He originally thought that there might be
a viral link to obesity when he
heard that a viral epidemic killed
poultry in his native India. The
virus killed thousands of chickens,
yet they were still carrying excess
body fat. The United States did
not allow Dhuranda to import the
virus that was isolated in Bombay
when he moved to America. He
therefore began looking for a
human viral marker. After screening 52 obese people for antibodies to the virus, he found over
40% had it. They were also the
heaviest of the patients.
John Foreyt is an obesity
expert at Baylor College of Medicine in the United States. He
says, "The latest results do not
indicate that all obesity is caused
by viruses, but they strongly suggest that infection plays an
important role."
Adenoviruses are already
known to cause colds, diarrhoea,
and eye infections. Dhuranda
says, "This virus is probably associated with diarrhoea in humans,
and may be spread by unhygienic practices just like any other
pathogens that have an oral-faecal route. The ideal solution
would be some sort of vaccine, but this at least five years away."
Dhuranda emphasises that
much more research remains to
be done into the subject. Ad-36
could either cause obesity or be
one factor in the disease. It is
also still unclear as to why the
cholesterol and triglyceride levels are "paradoxically low" in
those carrying antibodies to the virus.
Jenny Blythe, Clegg scholar
studentBMJ 2000;08:303-346 September ISSN 0966-6494
