I was just wondering about the behaviour of swine flu v "ordinary" flu..

[furrycat]

Why don't we worry about normal flu mutating every year?

How come "ordinary" flu dies out every year while they are expecting swine flu to be around for a few years?

If someone got ordinary flu and swine flu at the same time, would it make the virus mutate?

furrycat -

seasonal flu does mutate each year. Its why people need annual vaccines. Usually scientists have a pretty good handle on how it is shifting and alter the vaccine as necc by choosing which strains to use.

Seasonal flu tends to spread almost entirely during winter months for a variety. things like, temp, humidity, sunlight, people being in close proximity. in tropical countries it doesnt tend to follow a seasonal pattern.

Pandemic Flu is a novel flu virus that very few (if any) have encountered before. It will continue to circulate until it has infected all potential candidates. (some people seem to not get infected interestingly)

As it does so it will shift (mutate) and yes it may well recombine with other flu viruses. (after all it is a combination of avian, swine and human flu viruses already) and make new strains. Scientists can't really know hopw that will go, not all mutations are bad news