Sars, the virus which emerged in China in February and spread to 32 countries, killing more than 800 people, might re-emerge in the autumn, say health experts.
Enormous efforts by public health doctors succeeded in containing the virus and eventually in interrupting transmission in its last bastions. Travel warnings were lifted from Canada, Hong Kong, Beijing and finally, earlier this month, Taiwan.
The World Health Organisation considers that the virus — believed to have originated in animals — has been ”pushed back out of its new human host”. But the WHO says now that ”the most pressing question is whether it will return”.
Nine expert opinions are published today in the Journal of Epidemiology and Community Health, which asks whether the Sars epidemic will recur. Three say categorically yes, four are uncertain and only two think that humans are safe from the virus.
Sars (sudden acute respiratory syndrome) is caused by a new coronavirus.
Abu Abdullah, research professor in community medicine at the University of Hong Kong, said: ”About one third of all common colds are caused by viruses from the same family and these show a winter and spring seasonality.”
He thinks that Sars could be the same. It emerged in the influenza season, which peaks between December and March. Better weather may have contributed to the epidemic tailing off.
Civet cats and other wild animals sold in food markets in southern China are believed to have been the source of the virus. ”If confirmed the animals will be a reservoir in ready contact with humans that could initiate a second Sars epidemic,” the professor writes.
Albert Lee, professor in community and family medicine at the Chinese University of Hong Kong, also thinks there is still a risk, particularly to people in poor living conditions. ”A Sars epidemic can easily recur if we do not have a healthy population, [and if we have] poor hygienic practice, inadequate infectious control measures, and poor living environment before the breakthrough in treatment and vaccine development,” he warns.
Rashid Chotani, assistant professor at the Johns Hopkins school of public health in Baltimore, says there is ”a strong possibility that the virus will re-emerge during the next winter season” and calls for better surveillance and preparedness as well as ”strict measures… to control and contain the virus in the animal markets”.
He adds that preparing for a possible pandemic ”could save thousands of lives as well as an enormous economic burden”.
Several of the scientists make the link with the deadly Ebola virus, which circulates in animal populations in Africa and then, under particular circumstances, jumps species and causes a human epidemic.
Martyn Regan, a Health Protection Agency consultant epidemiologist based in Chester, says Sars could, like influenza, still be present in the human population but unnoticed. Tests for Sars are not highly developed ”and consequently some cases will be missed”.
He added: ”How the next chapter on Sars will unfold will depend on effective targeting of enhanced surveillance programmes and rapid isolation of hospitalised cases.”
But Tze-Wai Wong, also from the Chinese University of Hong Kong, thinks that although another Sars epidemic is possible ”the probability of a large-scale epidemic is low”. He thinks that public health measures will contain any outbreak, now that the authorities are on the alert for the virus. – Guardian Unlimited Â