Researchers have lately found infection with a virus linked to obesity which increased fat cell production and makes fat cells fatter. The virus adenovirus-36 or AD-36 is linked to obesity and the phenomenon is called “infectobesity”. Research has also shown that 30% of the obese persons but only 11% of the lean persons have been infected by AD-36. Researchers have found evidence that Ad-36 has a direct effect on human fat cells. Infection of adult stem cells from human fat causes their transformation into pre-fat cells. These virus-infected cells contain much more fat than normal pre-fat cells which results in more fatter cells.
All cases of obesity may not be linked to the virus but there is enough evidence to show a link between viral infections and obesity. One particular Ad-36 gene, called E4Orfl, is the cause for the virus's obesity-related effects. The researchers are also in the process of finding why some people seem to become obese after Ad-36 infection while others don't. Another human adenovirus AD-37 has also been found to cause obesity.
The adenovirus Ad36—one of a family of about 50 viruses that cause colds, upper respiratory infections, eye inflammations and gastro intestinal problems is found to trigger obesity in humans and other animals. But obesity cannot be caused by one single factor; it is a combination of environmental and genetic factors that cause obesity. Doctors and researchers are giving the theory of the link between virus and obesity more credibility. They say that it is possible that the virus gets into the brain and affects the brain centers thereby affecting appetite. More tests to confirm the link will be useful in controlling the spread of obesity in the form of vaccines or anti viral therapy that can control the same.