It is not always after an infection with a flu virus that you are able to infect another person. When a flu virus infects you, there is usually a period within which the virus is most virulent within your body and other stand maximum chance of being infected by you. However, that is not to say that the virus will not infect other people during any other period of infection. Basically, it has been found out that when a person is infected with a flu virus, may it be of any category A B or C, from the second day till the fourth day, the virus is most infectious and any person coming in contact with such a person at such a time, stands the highest chance of infection.

However, there is a blessing here as well, because within ten days of running its course within the human body, the virus loses its capacity for infection. However, if you have a child at home who is affected with the virus then you may have to be over precautious because children are usually very much more infectious than adults. In children the virus can start infecting through transmission even after the first day of the child’s own infection. also, instead of the ten days infecting period in adults, the virus infecting the child’s body has an infecting period of fourteen days!

Now, transmission is usually through contact with infected substances or through aerosols formed in air between the virus and the atmosphere. The virus is also active outside the human body but the duration of activity are very limited, from five to ten minutes for dry surfaces and fifteen minutes maximum for wet surfaces. However, if the virus is in mucus or any such thing then its longevity outside the body is high. Therefore you stand a chance of infection even if you are holding just a bank note.

It is quite scary to know that influenza not only affects our respiratory system but also our whole body at many a times. Although there are flu viruses which cannot descend below the lungs and the trachea, there are more virulent types that can affect a variety of body parts. It has all got to do with the proteases which is found in the body and which helps the virus cell to cleave itself to form two cells, basically multiply. Now, certain strains require a protease which is found only in the lungs and the tracheal tissues and so infection cannot spread to the other parts, however, the more virulent types can attain similar cleavage with the help of a wide variety of proteases, therefore the chance of spread to various other organs.

Also, flu causes tissues damage and may lead to a cytokine storm that renders it lethal and life threatening.