Swine Flu Spreads Easily in Ferrets, Doesn't Become Super Bug

Swine Flu Spreads Easily in Ferrets, Doesn’t Become Super Bug


By Rob Waters

Sept. 1 (Bloomberg) -- Swine flu spread faster than seasonal influenza strains after researchers infected ferrets with the viruses. The different strains didn’t combine to create a more-resistant super bug.

The study findings suggest that swine flu may be better suited than other strains to thrive inside humans and is likely to dominate the 2009 flu season, said Daniel Perez, a University of Maryland researcher who led the research. Preliminary results were published today in the journal PlOS Currents: Influenza.

“The good news” is that swine flu “is unlikely to recombine with seasonal flu to create a super bug, a more virulent strain,” Perez said in a telephone interview today. “The bad news is that it will be highly transmissible and we should be aware that we do need to vaccinate against this virus to prevent its spread.”

Ferrets respond to flu much as humans do and are considered predictors of how influenza strains will reproduce in humans and affect health, Perez said.

Swine flu, also known as H1N1, outperformed two strains of seasonal influenza by replicating more extensively within the animals, the researchers from University of Maryland in College Park, Maryland, found. Other ferrets exposed to the infected animals developed flu symptoms and elevated levels of swine flu.

Perez and his team conducted their experiment in four groups of animals. In each group, one ferret was given a nasal spray containing the H1N1 virus and another seasonal flu strain. Another ferret was placed in the same cage and a third was put next door, on the other side of a wire mesh, so it breathed the same air.

Developed Symptoms

All 12 ferrets developed symptoms. Some of the animals that were infected with both the swine flu and a seasonal flu variant known as H3N2 developed diarrhea and weight loss as well as respiratory symptoms, the researchers found.

In the past, some influenza viruses have genetically recombined with other viruses to form newer, more dangerous strains. According to the team’s initial analysis, this didn’t happen in the ferrets, Perez said.

“Our study suggests that the H1N1 virus has everything it needs to transmit and doesn’t seem to require any additional recombination or modification to transmit efficiently,” Perez said.