Indonesian agricultural officials slaughter birds near site of bird flu outbreak in Surabaya (Feb. 06 file photo)

The World Health Organization has confirmed that five more Indonesians have died of bird flu, bringing the country's death toll from the disease to 30.

Officials from the U.N. agency and the Indonesian health ministry say four of the victims were members of the same family and were infected at a family gathering in North Sumatra province.

The fifth fatality was a woman in the city of Surabaya on Java island.

Health officials are downplaying concern the family cluster is a sign that the deadly H5N1 virus has changed into a form easily passed between humans.

Meanwhile, officials from the U.N. Food and Agriculture Organization (FAO) say the H5N1 strain of bird flu has been found in a duck in Laos. It is the first case of the virus in Laos since early 2004.

The virus has killed more than 115 people worldwide.

Some information for this report was provided by AFP, AP and Reuters.