New study gives researchers insight into avian flu

A new study supported by the National Institute of Allergy and Infectious Diseases recently tested pig and ferret susceptibility to the H7N9 avian influenza virus.

Researchers chose to study ferrets because ferrets become infected and transmit disease in a similar fashion to humans. Researchers used this mammalian model to see how ferrets were affected by an isolated H7N9 virus, which lead to the death of a person this flu season.

Researchers infected six ferrets by dropping the H7N9 virus into their noses. After waiting 24 hours, researchers took six uninfected ferrets, placed three inside the cage with the infected ferrets and three in a cage nearby.

All three ferrets sharing the cage with the infected ferrets became ill, while one of three ferrets in the nearby cage became ill. Scientists concluded the virus is more easily transmitted by direct contact and less easily transmitted through the air.

Researchers also noticed the infected ferrets showed no symptoms before passing the virus onto the other ferrets. Researchers concluded the same risk of transmission exists for humans as well.

The same experiment was done with pigs as the mammalian model because pigs can provide an idea of how a strand of influenza adapts best to mammals and can develop into a pandemic. However, none of the uninfected pigs became infected, either in the same pen or next to it.

Infected animals showed signs of illness such as runny nose, sneezing and lethargy, but none became serious ill.