Secrets to the 1918 flu pandemic that killed at least 20 to 50 million worldwide have been uncovered – a group of three genes allowed the virus to invade the lungs causing pneumonia.
That information might be useful today in the development of new flu drugs, says the authors of the study published in today’s Proceedings of the National Academy of Sciences.
A similar mutation could occur again turning ordinary flu into a dangerous pandemic strain, reports Reuters.
In this study out of the University of Wisconsin School of Veterinary Medicine, Yoshihiro Kawaoka and colleagues at the Universities of Kobe and Tokyo in Japan, used ferrets to test their theory – mixing samples of the 1918 flu strain with modern seasonal flu.
Ferrets develop flu in much the same way as humans. In this case, finding the three genes killed the ferrets in the same way as the 1918 outbreak, infecting the lungs as well as the upper respiratory tract.
In 1918, the influenza epidemic infected about 500 million people worldwide – one third of the population - and killed 2.5 percent of victims. Generally these outbreaks killed one percent of the population. And otherwise healthy young adults died of severe pneumonia.
"We wanted to know why the 1918 flu caused severe pneumonia," Kawaoka said in a statement.
So researchers substituted a single gene from 1918 into the modern flu virus, then they added another, until they found a complex of three genes that allowed the virus to reproduce deeply in the lungs. The genes identified are the PA, PB1, and PB2, along with a 1918 version of the nucleoprotein or NP gene, reports Reuters.
"The RNA polymerase is used to make new copies of the virus," Kawaoka explains. Without the protein, the virus is unable to make new virus particles and spread infection to nearby cells.
Research out of Vanderbilt University, shows people who lived through the pandemic as children are still producing antibodies to the virus today, even though they are 91 to 101-years-old.
Researchers have determined that the immune system has a long-term memory, particularly to the first flu strain you are exposed to in your lifetime.
Pandemic experts expect that another severe and devastating flu pandemic will strike again. Many suspect that the H5N1 avian influenza virus holds the potential to go worldwide with deadly consequences. So far it has killed 247 of the 391 people it has infected. #