Research by scientists from the Max F. Perutz Laboratories points to new treatment options
The flu is caused by an infection with the influenza virus, which mainly attacks the upper respiratory tract - the nose, throat and bronchi and rarely also the lungs. According to the World Health Organization (WHO), around five to 15 percent of the population are affected by upper respiratory tract infections during seasonal flu outbreaks, and between 250 000-500 000 people die of the illness every year. However, a main cause of death in people having the flu is actually a secondary infection with bacteria.
Influenza increases susceptibility to bacterial infection
When we are sick with influenza virus, for many reasons our susceptibility to bacterial infection is increased. One type of bacteria that the immune system usually prevents from spreading and becoming harmful for us is called Legionella pneumophila. However in some circumstances, such as when we're infected with influenza virus, Legionella can cause pneumonia, an inflammatory disease of the lung that if left untreated can leave the lung permanently damaged and even cause death. Amanda Jamieson, the lead author of the report and a research fellow in the Department of Microbiology, Immunobiology and Genetics of the University of Vienna, started to study this phenomenon while working in the laboratory of Ruslan Medzhitov, an immunologist at Yale University School of Medicine, USA, and has continued the project in Vienna in collaboration with Dr. Thomas Decker at the MFPL of the University of Vienna and the Medical University of Vienna. "In our model system an infection with influenza and Legionella was fatal. We expected that this would be caused by the bacteria growing and spreading like crazy, but what we actually found was that the number of bacteria didn't change, which was a big surprise", says Amanda Jamieson.