Can you catch Swine Flu through flatulence?

Answer 1

Unlikely, unless more than gas comes out at the same time. Influenza viruses are not airborne, which would be required for the virus to somehow travel on the flatus from person to person. Unless there is much more than air and gasses expelled, it would not be possible.

When a person sneezes or coughs, droplets of respiratory secretions are expelled in a mist with some larger drops. Viruses can be contained in these respiratory droplets and that is how you can catch the flu from a person who coughs or sneezes and you breathe in the droplets from the air, or you touch a place where the droplets landed when they fell out of the air. The droplets are much heavier than air and will fall to the surfaces around the person who failed to cover their mouth and nose with a tissue (shame on them). Under most conditions, keeping a distance of around six feet from a person who is sneezing or coughing will keep you outside the distance the droplets carrying the virus can travel in the air before falling to the surrounding surfaces.

The person having flatulence is hopefully wearing clothing in your presence, which would act similarly to the tissue covering your mouth and nose when coughing and sneezing and the clothing would catch any "secretions" (fecal material) that might get expelled along with the air and gasses in the passing of the intestinal gas.

So, for you to catch Swine Flu through flatus, the person with the flatulence would have to be naked, and expelling droplets and not just gas. You would have to be close enough to the source to breathe those droplets in directly from the air, and that would be much much closer than six feet, because the force behind flatus is insignificant compared to the force of a sneeze or cough. It would likely be required that your nose be within a foot of the anus to be able to breathe the rectal fecal droplets. Otherwise, you would have to touch something the droplet fell on, and then transfer the virus contained in the droplets to your eyes, nose, or mouth with your hand. I know that I would be very unlikely to put myself in that place or do those things, and hopefully you and the person with flatulence would also not likely be in those positions.

Additional flatulence trivia:

The components of flatus are nitrogen (the most prevalent gas in the air), oxygen, carbon dioxide, hydrogen, and methane. Each person will have a different combination of those gases, and not all people have all gases in their flatus. That is dependent on the foods eaten, drinks consumed (carbonated drinks increase the carbon dioxide content), bacteria present in the gut, and some genetic components--since there seems to be an hereditary relationship to the production of methane in humans. These are all mostly odorless gases. The things present that create the odor are mostly sulfur from hydrogen sulfide, carbonyl sulfide, butyric acid, and skatole and indole which are compounds high in nitrogen.