The NIH reported that preliminary findings in ferrets suggest that the novel 2009 H1N1 influenza virus may outcompete human seasonal influenza viruses. NIH said that tests in animals showed that levels of the 2009 H1N1 virus rose more quickly than levels of the seasonal virus strains, and the new virus caused more severe disease. In line with previous findings by other research groups, the University of Maryland researchers also observed that the novel H1N1 virus was transmitted more easily from infected to uninfected ferrets than either of the two seasonal influenza viruses.
The researchers found no evidence that the 2009 H1N1 virus combined with either of two seasonal flu viruses to form new, so-called reassortant viruses. These findings suggest that while 2009 H1N1 virus probably will predominate in the coming flu season, there may not be biological pressure for the new virus to re-combine with other circulating viruses, the researchers said. The work was done by Daniel Perez, Ph.D., and colleagues from the University of Maryland. The researchers were supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.