AS a crack team of epidemiologists scours Hong Kong for fresh cases of a
killer strain of flu that has spread from chickens into people, there are fears
that the disease may already have taken hold in remote parts of China. The WHO
is now stepping up disease monitoring in the region.
Influenza experts are desperate to keep tabs on the new strain, fearing a
repeat of earlier pandemics that killed millions.
The alarm was sounded last week when three further cases of flu caused by the
virus H5N1 were reported by the Hong Kong authorities. The first human case of
H5N1 infection occurred in Hong Kong in May, when a three-year-old boy died.
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Experts are worried because H5N1, which kills poultry, has never been known
to infect people before. Initially, the WHO said the virus would probably only
cause mild disease, except in the sick or elderly. Doctors made this assumption
because the boy also suffered from Reye鈥檚 syndrome, an inflammation of the
brain.
But the WHO鈥檚 early advice is now looking unduly rosy. Already one of the
latest victims, a 54-year-old man, has died, presumably as a result of the
infection. 鈥淚 don鈥檛 consider 54 to be very old,鈥� says Daniel Lavanchy, the WHO鈥檚
chief medical officer for influenza in Geneva.
Epidemiologists are now looking for evidence that the virus is being passed
from person to person鈥攁 factor which would raise the spectre of a
pandemic. 鈥淚f there turn out to be human to human cases, that will be very bad
news indeed,鈥� says Lavanchy. So far it seems that each of the Hong Kong patients
could have caught the virus directly from poultry, but Lavanchy notes that the
possibility of human to human transmission has not been ruled out.
Flu strains that have jumped from other animals to people are thought be more
virulent because our immune systems have no experience of fighting them. The
strains that caused previous pandemics are thought to have come from pigs or
poultry.
But as the world鈥檚 attention focuses on Hong Kong, unconfirmed reports claim
that farmers in southern China have been found carrying antibodies to
H5N1鈥攕uggesting that the virus may have already have taken hold there.
Experts fear that resources in China are spread too thin to give a good
assessment of the situation. 鈥淪urveillance in China is a real problem. We have
to think of ways of beefing up the monitoring there,鈥� says Alan Hay, head of the
WHO鈥檚 collaborative influenza centre at the National Institute of Medical
Research in London. 鈥淲e鈥檙e very concerned about surveillance and we鈥檒l work with
the Chinese authorities to do what鈥檚 necessary,鈥� says a WHO spokesman in
Geneva.
The London centre, together with the three other international WHO influenza
centres in Atlanta, Tokyo and Melbourne, has already started working on a
vaccine against the H5N1 strain. But Hay says that it will be at least six
months before anything is available for widespread use.
