Two viruses and several types of respiratory infections could attack Bulgaria during the upcoming fall-winter season, experts have announced.

The head of the Bulgarian Institute on Microbiology in the Bulgarian Academy of Sciences, Angel Galabov, explained Monday that one of the viruses that would probably hit Bulgaria at the end of the year and the beginning of 2011 would be the flu Perth (AH3N2).

The virus would affect mostly elderly people, children and people with weak immune system. The symptoms would be the same as for a regular flu. It starts abruptly with high temperature, muscle ache, coughing and headache.

Galabov has explained that the Perth flu has caused the death of about 2000 people,which was not a big number for a seasonal virus. He pointed out that in the United States, about 50,000 people die every year from seasonal viruses and that the global number of victims could reach half a million.

Another dangerous infection that could hit Bulgaria this fall-winter season is the post-pandemic swine flu. According to Galabov, it would affect mostly young people, but it's lethality would be much lower than the one of a regular flu.