Health News

Is There an Obesity Bug?

July 28, 2000 -- Are you getting very fat even though your cholesterol level is low? You might have a bad case of the "obesity bug." More research is needed, but there may be many people who are extremely overweight just because they came down with a viral infection.

"People should know there is very little we can do about it right now," researcher Nikil V. Dhurandhar, PhD, tells WebMD. "We don't know it causes obesity in humans for sure. But there is no known treatment [for the virus] and no known vaccine as of today." Dhurandhar is chair of obesity research at Wayne State University in Detroit.

"This is, I think, an incredibly important and exciting finding," obesity expert David B. Allison, PhD, tells WebMD. "This research is very novel, very creative -- but a lot of very creative ideas turn out to be wrong. If it turns out to be right, this is a breakthrough. It is a previously undiscovered cause of human obesity." Allison, a researcher at Columbia University College of Physicians and Surgeons in New York, was not involved in the study.

Not much is known about the suspected obesity bug. Its name is human adenovirus 36, or Ad-36, a unique member of a family of about 50 viruses. Several members of this family cause about 5% of adult lung disease and pneumonia, but there is no established treatment. A vaccine against the two most common forms of adenovirus is currently used only by the military to prevent outbreaks of disease at training bases. Also, blood tests are not commercially available.

Dhurandhar first uncovered evidence of an obesity virus in India. While working on his PhD thesis in Bombay, he was struck by the discovery of a chicken adenovirus that killed baby birds. Instead of wasting away -- the usual course of a viral disease -- the animals actually became very fat. Contrary to what one would expect in obese animals and humans, the chickens had low blood levels of cholesterol and fatty acids. He tested obese residents of Bombay for evidence of infection with the chicken virus and found that many of these people tested positive -- even though chicken adenoviruses are not supposed to infect people. Those who tested positive for the chicken virus -- but not other obese people -- had low blood levels of cholesterol and fatty acids as well.

Dhurandhar came to the U.S. to pursue his studies at the University of Wisconsin, in Madison. But he ran into a major problem -- the U.S. Department of Agriculture was not about to let him import the chicken virus from India, where it is a major killer of domestic poultry. "This turned out to be a blessing in disguise, because it forced us to focus on the adenoviruses that are in this country," he says. He and colleague Richard Atkinson chose to look at Ad-36 because nobody had yet taken a close look at it -- a process he describes as "some logic, some luck -- mostly luck."