Spreading flu raises spectre of pandemic

Outbreaks of swine flu in Mexico and the US have the potential to cause a worldwide pandemic, the head of the World Health Organisation said on Saturday — but there are fears that it may already be too late to contain the outbreak. The US Centers for Disease Control said the spread of the virus cannot be contained.

WHO director-general Margaret Chan urged health authorities in all countries to be on high alert for unusual patterns of disease and any rise in severe flu or pneumonia cases. “This is an animal strain of the H1N1 virus and it has pandemic potential because it is infecting people,” Chan said.

WHO has warned for several years that a new virus strain could spark a human influenza pandemic that could sweep around the globe and kill millions.

The new H1N1 flu strain — a mixture of swine, human and avian flu viruses which has killed up to 68 people among 1,004 suspected cases in Mexico and infected eight in the US — is still poorly understood and the situation is evolving quickly, Chan said. “It would be prudent for health officials within countries to be alert to outbreaks of influenza-like illness,” added Chan.

Health officials worldwide should also be alert to large incidences of severe or fatal flu-like illness in groups other than young children and the elderly, the ages usually at highest risk from normal seasonal flu, she said. Most of the dead in Mexico were aged between 25 and 45.  

“Influenza viruses are notoriously unpredictable and full of surprises, as we are seeing right now,” Chan said. “We need to know how the virus is spread, what is the transmission pattern and whether or not it is going to cause severe disease and in what age group,” she said.

An emergency committee of 15 experts was meeting on Saturday to advise her about raising the world pandemic flu alert to 4 from 3. Such a high level of alert — meaning that sustained human-to-human transmission of a new virus has been detected — has not been reached in recent years, even with the H5N1 avian flu circulating in Asia and Egypt, and would “really raise the hackles of everyone around the world,” said Dr. Robert G. Webster, a flu virus expert.

The experts would also address the issue of travel advisories. “We do not yet have a complete picture of the epidemiology or the risk, including possible spread beyond the currently affected areas,” Chan said. “Nonetheless, in the assessment of WHO, this is a serious situation which must be watched very closely.”

Some Asian nations enforced checks Saturday on passengers and pork products from Mexico. Japan’s biggest international airport stepped up health surveillance, while the Philippines said it may quarantine passengers with fevers who have been to Mexico. Health authorities in Thailand and Hong Kong said they were closely monitoring the situation. “We have to remain alert,” said Dr Ashish Chandra Dhariwal, joint director, National Institute of Communicable Diseases, New Delhi. He said the situation would be assessed over the weekend and an advisory issued soon.

Mexico City said schools would remain closed and all public events suspended until further notice.

Meanwhile, even New York city schools reported cases of flu among over 75 school students, prompting officials to sterilise schools.