Iowa State University
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News Service

News Service:

Annette Hacker, director,
(515) 294-3720

Office: (515) 294-4777

12-31-07

Contacts:

Bruce Janke, Veterinary Diagnostic Laboratory, Veterinary Diagnostic and Production

Animal Medicine, (515) 294-1186, bhjanke@iastate.edu

Wenjun Ma, Veterinary Diagnostic and Production Animal Medicine, (515) 663-7703, wjma@iastate.edu

Tracy Raef, College of Veterinary Medicine, (515) 294-4602, traef@iastate.edu

Dan Kuester, News Service, (515) 294-0704, kuester@iastate.edu

Iowa State University researchers collaborate in identification of new influenza subtype not previously found in pigs

AMES, Iowa -- Two Iowa State University researchers, working in collaboration with scientists from around the Midwest, have identified and characterized a subtype of influenza in swine that had not been isolated previously from that species.

The virus, H2N3, is a subtype of influenza A virus that is found frequently in birds, such as ducks, but never before in hogs. This virus contains genes from both avian and swine influenza viruses.

The findings are published in the current edition of the journal Proceedings of the National Academy of Sciences of the United States of America.

"This is very important since this is the first time H2 virus has been found in a mammalian species other than humans. Experimentally, the virus also was able to infect mice and ferrets," said Wenjun Ma, a researcher at Iowa State University's College of Veterinary Medicine.

Researchers think the swine were infected because water from ponds where migrating waterfowl congregated was used for cleaning barns and watering the pigs.

"Most hog housing units are confined enough that ducks aren't going to be flying into them," said Bruce Janke, a veterinary pathologist at the College of Veterinary Medicine.

"What has probably happened is that these viruses from ducks were ingested or breathed in by the pigs, then reassortment occurred in pigs," said Janke.

Janke says that is a concern among some scientists because the virus found in the pigs is closely related to the type of influenza virus that caused the Asian flu epidemic in 1957, which was an H2 strain.

Currently, type influenza A strains found in humans are normally H1 or H3 subtypes.

So far, Janke says, there is no threat to human populations.

"This particular virus hasn't turned out to be a problem," Janke said.

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Quick look

Iowa State University researchers have helped identify and characterize a subtype of influenza in swine that hadn't been found in the species. The subtype, H2N3, is frequently found in birds. The finding was recently published in the Proceedings of the National Academy of Sciences of the United States of America.

Quote

"This is very important since this is the first time H2 virus has been found in a mammalian species other than humans. Experimentally, the virus also was able to infect mice and ferrets."

Wenjun Ma, a researcher at Iowa State University's College of Veterinary Medicine