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PARIS: Swedish scientists say that Tamiflu—the
frontline weapon in any bird-flu pandemic—cannot be broken down by
sewage systems and this could help the virus mutate dangerously into
a drug-resistant strain.
Countries around the world are
stockpiling Tamiflu in the belief it will help curb any future
outbreak of H5N1 avian flu among humans.
Tamiflu, whose lab name is
oseltamivir, is not a cure for flu but can ease its symptoms, thus
aiding vulnerable patients such as the elderly, and reduce the time
of illness, thus easing the burden on caregivers.
Scientists led by Jerker Fick, a
chemist at Umea University, tested the survivability of the Tamiflu
molecule in water drawn from three phases in a typical sewage
system.
The first was raw sewage water;
the second was water that had been filtered and treated with
chemicals; the third was water from “activated sludge,” in which
microbes are used to digest waste material.
Tamiflu’s active ingredient
survived all three processes, which means that it is released in the
wastewater leaving the plant.
The finding is important because
of the risk that Tamiflu, if overprescribed, could end up in the
wild in concentrations high enough to let H5N1 adapt to this key
drug, the authors say.
Flu viruses are common among
waterfowl, especially dabbling ducks such as mallards, which often
forage for food near sewage outlets.
“The biggest threat is that
resistance will become common among low pathogenic influenza viruses
carried by wild ducks,” said co-author Bjoern Olsen, professor of
infectious diseases at the University of Uppsala and University of
Kalmar.
These avian viruses could then
recombinate with ordinary human flu viruses, creating new strains
that are resistant to Tamiflu, he said.
--AFP
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