YANGON, April 2 (Reuters) - Birdflu has struck a fifth area on the outskirts of Yangon, probably spread by farmers moving fowl to market, the official New Light of Myanmar reported on Monday.

Officials killed fowl in the immediate area around the infected farm, it said.

"It has been assessed that bird flu virus spread to the affected farm due to transport and sale of chickens, ducks and quails in the region where there was an outbreak of bird-flu in February," the paper said.

All five outbreaks of the H5N1 virus since then have been on the northern outskirts of Yangon and about 40,000 fowl have been slaughtered, but a Health Ministry official said there had been no infections of humans.

The virus is known to have infected at least 275 people in 12 countries since 2003 and has killed at least 167 of them in 10 countries, most of them in Indonesia and Vietnam.

Health experts fear it could mutate into a form which could pass easily for person to person, which now it cannot, and set off an epidemic.