Q: In case of human-to-human transmission of swine flu, how long does the H1N1 virus survive outside the body? Is swine flu going to stay like normal flu for a long time? Is it a one time or a seasonal/annual problem?

A:Swine flu is just a variation of Influenza A and can be expected to behave like other flu viruses. I expect it will be around for a while, perhaps even into the next season or longer. The epidemiology of various pandemics of influenza has clearly demonstrated the cyclic nature of the condition.

Variants of the flu virus have caused many pandemics, and in some cases have killed thousands of people. As 'flu viruses go, Swine 'flu is relatively mild so far. Many more persons are infected and suffer very mild and undiagnosed forms of the infection. Only severe infection comes to our attention and are tested. Almost all persons who get infected, even the very mild cases that do not bother the person and are never diagnosed develop immunity. Ultimately the level of immunity in the community will build up (herd immunity) and transmission of swine 'flu will begin to slow down.