A new strain of the bird flu virus spreading around the world is more infectious to humans, a study lead by a U.S. researcher has found.

Led by Yoshihiro Kawaoka of the University of Wisconsin-Madison, the new study found the H5N1 virus has apparently mutated into a new strain that increases the risk of a human pandemic due to its increased level of communicability, The Independent said Saturday.

Kawaoka said the new strain does not represent a fully pandemic strain of the virus, but warned the mutated virus has been found in both Europe and Africa.

"The viruses circulating in Europe and Africa all have this mutation," the doctor said. "So they are the ones that are closer to human-like flu."

Since the virus was first reported in 2003, 329 people worldwide have been infected according to World Health Organization figures.

Those figures also show that of those infected during that time period, 201 have died as a result.

The British newspaper said health groups worldwide have prepared for a possible pandemic by collecting anti-flu drugs and preparing emergency treatment plans.