Swine flu resembles 1918 pandemic, more likely to cause pneumonia

Posted Jul 13, 2009 by Michael Krebs
According to researchers in a report on Monday, the H1N1 swine flu virus has disturbing similarities to that of the 1918 pandemic that killed millions worldwide. The new flu also causes pneumonia more than regular flu viruses.
CDC Influenza Growth on Canine Kidney Cells
Examination of a culture flask containing Madin-Darby Canine Kidney epithelial cells (MDCK), and looking for any signs of growth in a stock of influenza virus.
CDC/ Laura R. Zambuto
The H1N1 swine flu virus has characteristics that are disturbingly similar to those of the 1918 flu pandemic that killed millions of people worldwide. Researchers reported Monday that the H1N1 virus has a greater ability to attack and infect the lungs than common seasonal flu viruses, making it a much greater threat than public health officials have been announcing prior.
"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," according to a report on
The researchers also confirmed what others have found: that people who survived the 1918 pandemic have extra immune protection against the current H1N1 animal.
"When we conducted the experiments in ferrets and monkeys, the seasonal virus did not replicate in the lungs," Yoshihiro Kawaoka of the University of Wisconsin, who led the study, told MSNBC. "The H1N1 virus replicates significantly better in the lungs."
It is estimated that the H1N1 virus has already infected more than 1 million people worldwide - and has killed at least 500.
"There is a misunderstanding about this virus," Kawaoka said in a statement. "There is clear evidence the virus is different than seasonal influenza."
The 1918 pandemic is estimated to have killed between 40 million and 100 million people worldwide.