A cold-like virus may cause obesity, new experiments suggest. Researchers at the University of Wisconsin in Madison have found that mice and chickens infected with a common human virus put on much more fat than uninfected animals. They have also discovered that the same virus is more prevalent among overweight people, a strong indication that it may also cause obesity in humans. In four experiments, the Wisconsin researchers inoculated chickens and mice with adenovirus-36, a member of a viral family that includes about 50 strains.
Most adenoviruses cause colds, diarrhea or pinkeye.
After several months, animals infected with adenovirus-36 weighed only 7 percent more on average than those without the virus, but their bodies contained more than twice as much fat. ''This is the first human virus that has been shown to cause obesity in animals,'' said Nikhil Dhurandhar, one of the study's authors. It is also the first virus the researchers looked at, raising the possibility that other human viruses may also cause obesity. Dhurandhar and his colleagues picked adenovirus-36 simply because little is known about it and the strain is relatively easy to work with. The latest results do not indicate that all obesity is caused by viruses, Foreyt said. There's just so much more we need to do on this before we can say anything definitive,'' said Richard Atkinson, a University of Wisconsin professor and author of the study.