Maggie Fox
Reuters
July 13, 2009
WASHINGTON (Reuters) The new H1N1 influenza virus bears a disturbing resemblance to the virus strain that caused the 1918 flu pandemic, with a greater ability to infect the lungs than common seasonal flu viruses, researchers reported on Monday.
Tests in several animals confirmed other studies that have shown the new swine flu strain can spread beyond the upper respiratory tract to go deep into the lungs making it more likely to cause pneumonia, the international team said.
In addition, they found that people who survived the 1918 pandemic seem to have extra immune protection against the virus, again confirming the work of other researchers.
When we conducted the experiments in ferrets and monkeys, the seasonal virus did not replicate in the lungs, said Yoshihiro Kawaoka of the University of Wisconsin, who led the study.
The H1N1 virus replicates significantly better in the lungs.
The new swine flu virus has caused the first pandemic of the 21st century, infecting more than a million people, according to estimates, and killing at least 500. The World Health Organization says it is causing mostly moderate disease but Kawaoka said that does not mean it is like seasonal flu.
