F Greenaway. Am. J. Physiol. Regul. Comp. Physiol. (2006) Vol.290 p R188 – R189
Human adenovirus 36 (Ad 36) was first described in 1980. Since then obesity rates have more than doubled.
Symptoms of respiratory illness caused by adenovirus infection range from the common cold syndrome to pneumonia, croup, and bronchitis. Ad 36 is transmitted by direct contact, faecal-oral transmission, and occasionally, waterborne transmission (e.g. swimming pools).
Over the years, evidence from animal experiments show consistently that animals and humans infected with Ad 36 have higher numbers of fat cells. Humans with antibodies to Ad 36 also tend to be of heavier weight, even in discordant twins.
Other adenoviruses have been tested but none of these have this effect on humans.
Increased numbers of fat cells is not sufficient in itself to create obesity, but it helps. Obesity does not always follow infection.
Ad 36 is now in general circulation in the human population, cause of infection would be difficult to prove; most illness caused by Ad 36 is not serious enough to warrant thorough investigation.