A CLUSTER of human bird flu cases among relatives and possibly health workers in Vietnam may show the virus is changing into a form that can be passed on by humans, the World Health Organisation said.

A man whose brothers contracted bird flu has tested positive for the deadly virus, Vietnam’s state-controlled media reported today, as the World Health Organisation said it was investigating the possibility that one of the siblings passed the disease to another.

Vietnam today reported two new suspected cases of bird flu in humans as outbreaks among poultry spread to all parts of the country.

Laboratory tests have confirmed that bird flu claimed the lives of two more people, bringing Vietnam’s death toll to eight, officials said today.