Infectobesity: Obesity of Infectious Origin
Ad-36 Virus Signals the Body to Make Fat Cells
In a prior post, Is Obesity Contagious?, I ended the article with a reference to a group of chubby lab mice who were placed in the same quarters as a group of lean lab mice. The lean mice seemed to gain weight simply because they were exposed to the chubby mice. The bulk of the article explained why obesity is more a social contagion than something viral.
Well, hello again to lab mice and the viral theory… and chickens. Let’s not forget about the chickens.
Meanwhile, in Bombay...
Clinician Nikhil Dhurandhar and his boyhood friend and veterinary researcher Sharad M. Ajinkya were discussing the SMAM-1 virus and the thousands of deaths it caused among chickens in India in the early 1980s. Ajinkya noted that the infected chickens had all been fat in the area of the abdomen. Dhurandharr wondered aloud if it was the virus that was causing the added weight.
Testing was initiated, and it was discovered that healthy chickens who were given the SMAM-1 virus did gain significant amounts of weight.
The next step was the testing of obese people to see if they had antibodies for SMAM-1. From a sample of 52 patients, 10 were found to have antibodies. Those ten also were heavier than their 42 peers and more of their body weight consisted of fat. Dhurandhar and his theory that obesity might sometimes be viral exported to the United States and were met by a wholly unenthused medical community.
After an extended period, Dhurandhar was given employment in a Wisconsin lab where he tested the human adenovirus-36 to determine what effect it had on weight gain.
As it now stands, Dhurandhar has shown that when humans are infected with the Ad-36 virus, the body is told to make fat cells although why this happens is not clear.
"Infectobesity" the Ad-36 Viral Infection
The term coined to describe viral charged weight gain is the self-explanatory infectobesity. Research has shown that almost 30% of obese people have been infected with the Ad-36 virus as opposed to 11% of lean people.
So, what does it all mean?
Is Obesity Transmitted through a Common Viral Infection?
Researchers recently analyzed 10 studies consisting of 2,870 subjects that explored the association between Ad-36 infection and obesity. They found that the body mass index of people infected by Ad-36 is much higher than the body mass index of people who are not infected. They also found that the Ad-36 infection correlates with a higher risk of obesity.
The overall conclusion of the meta-analysis is that people who test positive for adenovirus 36 are more prone to weight gain and obesity than people who have never been exposed to the virus. These findings imply that further research may confirm that weight gain in humans is at least partially the result of an infection.
So, if you should find yourself in the company of fat chickens or chubby lab mice, you might want to give your hands a thorough washing. After all, you never know, right?