While some researchers search for the roots of obesity in our genes, others investigate
infections. Scientists have known for two decades that, surprisingly, certain viruses can cause
birds or mammals to become fat. Now scientists think they have tracked down a bug that can
cause obesity in people.
2 The alleged culprit is human adenovirus-36, or AD-36. A study published in 2002
showed that AD-36 injected into monkeys causes dramatic weight gain. In some animals, the
injected virus caused body fat to triple. Its unethical to inoculate people with viruses, of course.
But in an analysis of 1,000 people, the scientists found that those with AD-36 antibodies a sign
that they have been infected are significantly more likely to be overweight.
3 How could a virus make you fat? When fat cells are exposed to AD-36, they begin to
multiply. We are not saying all obesity is caused by a virus. Genes, metabolism, and habits
all play a role, the scientists acknowledge. But at least one other possibility appears to be
infection.”
4 As yet, no one knows how widespread AD-36 may be, or how big a role it might play in
the current obesity epidemic. If the scientists suspicions prove correct, the next step would be to
develop a vaccine.