Study leader Richard Atkinson, emeritus professor of medicine at the University of Wisconsin at Madison, Wis., said a fat virus could help explain the worldwide obesity epidemic, The Age reported Friday.

Jury Still Out

Atkinson research has shown that chickens, mice and marmosets become fatter after becoming infected with AD-36, a human adenovirus that usually causes colds, eye infections and diarrhea.

Tests on more than 500 Americans found about 30 percent of obese people had been exposed to the virus, compared with 11 percent of non-obese people.

However, Nick Martin, a professor at the Queensland Institute of Medical Research, who collaborated on the study, said his analysis found no link between Ad-36 infection and body mass index.