Human H5N1 cases spark fears that virus may have mutated
The government is concerned the bird flu virus might have mutated, and there are more chickens that are infected but not showing any symptoms, after the mainland reported four human cases not connected with a poultry outbreak.
Mainland authorities were investigating the bird flu cases to prevent the spread of the virus, Secretary for Food and Health York Chow Yat-ngok said yesterday.
'There are two main areas we are concerned about. One is that if there is no avian flu outbreak in poultry and yet there are human cases, does that mean the virus has changed?' said Dr Chow.
'Secondly, we are worried about whether there are more so called 'silently infected' chickens that actually might be carrying the virus and transmitting the disease, and yet do not show any symptoms or die from those illnesses.'
The two possibilities had yet to be examined by mainland authorities, he said, adding that there was no sign that bird flu had been transmitted from human to human.
Risk of bird flu is higher during winter, but he said the government did not expect a surge in cases over the Lunar New Year as long as people did not carry living poultry across the border.
The World Health Organisation said it expected the Ministry of Health to continue to keep it updated on the H5N1 cases, and advised people to avoid contact with poultry during the Lunar New Year.
The UN agency said it was 'prepared to provide technical assistance if requested' - a phrase used by the WHO to encourage countries to report cases of bird flu promptly so an international team can be sent to help investigate the cases.
The Ministry of Health on the mainland has informed the WHO China Office of all four cases.
The WHO's global pandemic alert level remains at Phase 3, meaning 'no or very limited human-to-human transmission'.
'During the Chinese New Year holiday season, when people are more exposed to poultry as poultry consumption rises, people are urged to maintain normal precautions against avian influenza, such as ensuring all poultry is well cooked and always washing hands after contact with raw meat,' the organisation said yesterday.
Since the global resurgence of H5N1 in 2003, there have been 34 cases on the mainland, in 22 of which the victim has died, including a 27-year-old woman on Saturday and a migrant worker who died in Beijing earlier this month.
Meanwhile, the Centre for Health Protection controller Thomas Tsang Ho-fai warned of the coming flu season, which covers the next four weeks.
There were as many as 100 institutional outbreaks a week during last year's peak period, and the centre expected 20 to 30 outbreaks per week this year.
The centre will update lists of institutions with flu outbreaks every 24 hours on its website.
It also sent schools updated guidelines to tackle the illness, including criteria on when to suspend classes.
High risk
The mainland has reported 34 human cases of H5N1 since 2003
Out of those, the number of cases that have proved fatal is: 22
