Indonesia has passed the incubation period of bird flu virus after the outbreak killed three people in the outskirts of Jakarta, but the disease was still possible to spread as the method to eliminate the virus was questionable, ministers and WHO officials said here on Wednesday.

Indonesian Health Minister Siti Fadilah Supari said that if one of the affected poultry still lived, it could contract the virus to human.

"As long as there are still chicken with bird flu, the disease can spread," Supari told Xinhua.

Meanwhile, Technical Officer of the World Health Organization ( WHO) Steven Bjorge told Xinhua that the practice of culling was still very much questionable.

"(The current culling method) was developed from the experience in the developing countries, where poultry raising is very concentrated in almost factory-type situation. Large farm that can be easily controlled. (But) in Southeast Asia and in Indonesia there are so many chickens living in back yard," said Bjorge.

To overcome the problem, the WHO officer proposed a field research to determine what was the right way and how to implement it.

"So, I want to emphasize that even though there are these recommendations for culling and vaccination, it is not clear how this can be implemented in the environment of Southeast Asia," he said.

Indonesia has conducted selective culling to prevent further spread of the H5N1 virus.

The virus has spread to 21 provinces out of 33 since late 2003, killing over 10 million fowl. The virus spread to pigs in Indonesia on Java island earlier this year.

Source: Xinhua