Twenty-five years ago, researchers discovered that certain viruses can cause obesity in some animals. A decade ago, they extended the finding to people. Now, a team reports that one such virus works by transforming adult stem cells into fat-storing cells. The finding supports the notion that some cases of obesity may be infectious.
Magdalena Pasarica of Louisiana State University in Baton Rouge, who led the new work, stresses that obesity has many causes, including genetic factors, overeating, and a sedentary lifestyle. In some people, however, adenovirus-36 may be the culprit, she says. Adenoviruses cause colds, but adenovirus-36, apparently, does more.
In a 2005 study of 502 obese and normal-weight people, researchers reported that 30 percent of the obese group showed signs of previous adenovirus-36 infection, while only 11 percent of the lean group did.