The regional director for the World Health Organisation (WHO) in the Western Pacific has complained that Asian countries take too long to report some human cases of bird flu and this could hamper any efforts to contain a possible pandemic.

Shigeru Omi, one of WHO’s top officials says these countries need to improve their capacity to quickly detect and report cases of the H5N1 virus.

Omi says the window of opportunity for containment is very narrow, and means rapid containment measures must be carried out at least two to three weeks after detection of a potential pandemic event.

Omi was speaking to the WHO’s Executive Board, and said that up to now, only half of the reports for human H5N1 cases had met this target. Some reports he said have been received as late as one or two months after disease onset.

Omi did not single out which Asian countries were the culprits.

In 2003 China was widely criticised for its cover-up of the SARS virus, contributing to its eventual spread around the globe.

Early this week China reported its 10th human case of bird flu, in a 29-year-old woman from the southwest Sichuan province.

According to China’s health ministry the woman became ill with a fever on January 12 and is in a critical condition in hospital.

The WHO spokeswoman is checking for more information from Beijing on this latest case.

To date six of the 10 people infected in China have died.

The latest case in China, appears not to have been preceded by an officially confirmed outbreak of H5N1 among poultry in the area.

According to David Nabarro, U.N. coordinator for avian and human influenza, Chinese authorities are being repeatedly reminded of the need for openness.

The size of the country and the population makes it difficult for the Chinese government to be sure that measures taken are always of the standard that the Chinese government wants, but by dialogue with the Chinese good progress is being seen, says Nabarro.

China has said they are gradually improving their surveillance and reporting systems.

To date the bird flu virus has killed at least 82 people in six countries since late 2003.

The disease remains one contracted from close contact with sick birds, but there are fears it could mutate into a form that can pass easily from person to person, sparking a pandemic.

The WHO believes that if a pandemic strain of the virus emerges, it may be possible to halt human-to-human spread, but only if stringent measures including distribution of antiviral drugs and restrictions on movement of people are taken quickly.