The World Health Organization says that while there have already been three deaths from bird flu in China this year, there are no signs the deadly disease is becoming a bigger problem.

In a statement Wednesday, the WHO's top representative in China, Hans Troedsson, says the three recent cases were not unexpected considering the winter season.

Bird flu tends to be more active during the colder months of the year.

Troedsson also stressed that all three cases involved people who contracted the disease from poultry, not from human to human transmissions.

China has the world's largest poultry population and is at the center of the fight against bird flu, which scientists fear could mutate into a form that could pass easily between people, sparking a pandemic.

The World Health Organization says China has had 20 bird flu deaths and 30 cases since the outbreak began in 2003.