Sources: Gary Anderson, 785-532-4454, firstname.lastname@example.org;
and Juergen Richt, 785-532-4401, email@example.com
News release prepared by: Erinn Barcomb-Peterson, 785-532-6415, firstname.lastname@example.org
Tuesday, Aug. 11, 2009
SIDEBAR: HOW DO FLU STRAINS GET THEIR NAMES? K-STATE INFECTIOUS DISEASE AND DIAGNOSTICS EXPERTS EXPLAIN
MANHATTAN -- H1N1, H1N2, H2N3, H3N1, H3N2, H5N1: What looks like a jumble of numbers and letters to most of us actually tell scientists quite a bit about particular strains of influenza viruses, according two Kansas State University infectious disease experts.
Gary Anderson is a professor and director of K-State's Veterinary Diagnostic Laboratory. Juergen Richt is the Regents Distinguished Professor at K-State's College of Veterinary Medicine and a Kansas Bioscience Authority Eminent Scholar.
They explained that influenza subtypes get their names from the unique combination of proteins on the outer layer of the virus. The H stands for hemagglutinin, for which there are 16 types, and the N is for neuraminidase, for which there are nine types.
Richt said that in mammals -- humans, pigs, horses, dogs, marine mammals and the like -- only a few of these H's and N's can be consistently isolated, whereas all 16 H's and nine N's have been found in waterfowl and seabirds. He said that when mammalian virus strains meld, or "mate," with avian strains they may become virulent in other animals like humans and in pigs.
Because these proteins are on the outer layer of the virus, they make first contact with the receptors that line the animals' respiratory tracts and with their immune systems. That also means these are the genes most likely to be altered, resulting in new, mutated strains of flu, the researchers said.
Novel viruses often are a combination of two or three viruses, Richt said. So, a particularly virulent virus like the pandemic H1N1 flu virus contains genes from human, swine and avian strains.