Bird flu cases are investigated

International health experts are investigating Pakistan’s first outbreak of bird flu in people to determine whether the virus was transmitted through human-to-human contact, officials said.

Four brothers -- two of whom died -- and two cousins from Abbottabad, a small city about 30 miles north of Islamabad, were suspected of being infected with the H5N1 virus, World Health Organization spokesman Gregory Hartl said.

Four WHO experts have been sent to Pakistan to investigate, Hartl said. The H5N1 virus has killed at least 208 people worldwide, mostly in Southeast Asia and China.