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.
"It also suggests that pigs could have played a role in maintaining and spreading the 1918 human pandemic influenza virus."
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 experimental infections in swine. The 1930 virus was chosen as a virus because it is thought to be a descendent of the 1918 virus, Richt said.
The researchers did not find a significant difference in effects from the 1918 and 1930 viruses in infected pigs. This was surprising, since the 1918 virus killed more than 20 million people and was lethal to ferrets, mice and macaques. Another surprising finding from the study was the rapid antibody response in the animals infected with the 1918 virus, which is not typically reported for the swine influenza virus.
Richt said he plans to conduct a follow-up project that will study what makes a swine flu virus a pandemic flu virus.
http://www.physorg.com/news160309140.html
Study says 1918 flu resulted in current lineage of H1N1 swine influenza viruses
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