Some people remain healthy, when faced with an influenza virus. Others are sure to catch it. The scientists believe that genes can be an explanation to this phenomenon.
The virus is transmitted via small droplets that enter the environment with coughing and sneezing. A simple cough can lead to about 100,000 viral particles getting into the environment. And when you sneeze, their number increases to 2 million. Moreover, the virus is very contagious (it annually affects from 5% to 15% of the population).
The reaction varies greatly. Some people may completely fall out of life, getting sick. However, 30-50% of the people are more resistant to the virus. That is, their body removes the virus from the system more efficiently.
U.S. scientists have analyzed the expression of genes in the people, infected with influenza virus. Thus, 17 volunteers have been infected with the H3N2 virus, which is responsible for seasonal outbreaks of infection. During the period of five days, blood samples of these volunteers were taken every eight hours. As a result, of the 17 infected people nine volunteers fell ill. And other people showed no symptoms of the flu, although they received the same concentration of the virus. It turned out that the reaction directly depended on the expression of many genes.
The people, who got ill, activated the genes involved in the production of inflammatory compounds and stress response. And the healthy volunteers, by contrast, activated the genes responsible for the anti-inflammatory response.