In 1918 a human influenza virus known as the Spanish flu spread through the central United States while a swine respiratory disease occurred concurrently. A Kansas State University researcher has found that the virus causing the pandemic was able to infect and replicate in pigs, but did not kill them, unlike in other mammalian hosts like monkeys, mice and ferrets where the infection has been lethal.
Juergen A. Richt, Regents Distinguished Professor of Diagnostic Medicine and Pathobiology at K-State's College of Veterinary Medicine, studied the 1918 Spanish flu pandemic with colleagues from the Canadian Food Inspection Agency, U.S. Department of Agriculture and Mount Sinai School of Medicine.
Their research supports the hypothesis that the 1918 pandemic influenza virus and the virus causing the swine flu were the same. Richt said the virus was able to infect and replicate in swine and cause mild respiratory disease. The 1918 virus spread through the pig population, adapted to the swine and resulted in the current lineage of the H1N1 swine influenza viruses. The researchers' study is published in the May 2009 Journal of Virology.
"This study emphasizes that an influenza virus, which is known to induce a lethal infection in ferrets and macaques, is not highly virulent in pigs, indicating a potential resistance of swine to highly virulent influenza viruses," Richt said. "It also suggests that pigs could have played a role in maintaining and spreading the 1918 human pandemic influenza virus."
Swine flu is a respiratory disease of pigs caused by type A influenza that regularly causes outbreaks of influenza among the animals and can be transmitted to humans. It is a typical zoonotic agent. While swine flu was first recognized as a disease in 1918, there also were reports of the influenza occurring in the Midwest in 1930.
For the study, the researchers used the 1918 pandemic virus and a 1930 H1N1 influenza virus for e
|Contact: Juergen A. Richt|
Kansas State University