There is no sign of the global SARS outbreak abating, with a worrying surge in new cases in Hong Kong on Friday, and a senior Chinese health official warning that the outbreak is not under control.
Epidemiologist Zhong Nanshan, director of the Respiratory Disease Research Institute in the Guandong province where SARS originated, disputed the Chinese government鈥檚 claims to have controlled SARS. 鈥淟ooking at this from a medical point of view, this disease has not been effectively controlled at all,鈥� he said. 鈥淭he origin of this disease is still not clear, so how can you say it has been controlled?鈥� He said 鈥渃ontained鈥� might be a better description.
Following initial work, the World Health Organization is to strengthen its investigative team in China. 鈥淭his is necessary for us to have a better understanding of the disease and develop more effective control and treatment strategies for SARS,鈥� says Hitoshi Oshitani, a WHO regional adviser in Manilla, the Philippines.
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By Friday, Severe Acute Respiratory Syndrome (SARS) had killed at least 117 people and infected over 3000 in over 30 countries. The key problem hampering the efforts of health officials to halt the outbreak is their continued lack of understanding about how the virus that causes the disease spreads.
As a result, draconian protective measures are being implemented in many countries around the world, with thousands being held in quarantine. On Friday, the Hong Kong authorities also barred people who have had close contact with SARS victims from leaving the region. Police have hunted down a number of people who fled quarantine.
In Singapore, the authorities aim to ensure compliance by installing internet-linked cameras in the homes of quarantined people. And in Canada, blood donations from people who have visited SARS-affected regions have been stopped, as a precaution.
Super-spreaders
Most SARS victims are either closely related to other victims or healthcare personnel working with patients. The virus probably spreads via direct inhalation of the body fluids expelled by coughing, or by touching surfaces soon after they are infected.
But investigators are still examining how some unrelated people have contracted SARS. 鈥淪uper-spreaders鈥�, who survive the disease but are highly infectious, are one possibility. A young Singaporean woman is now believed to be linked to virtually all of that country鈥檚 130 cases.
New information has also emerged from the investigation of the Amoy Gardens housing complex in Hong Kong, where 200 resident caught SARS. The virus was found in basins and toilets, say officials, suggesting the virus travelled through the clogged sewage system. Malik Pieris, head of virology at the University of Hong Kong, also reports that tests show the virus can survive in faeces.
Speculation that rats or cockroaches can spread the disease have been dismissed, as have Russian claims that the SARS virus is a biological weapon.
Permanent fixture
New studies published in the New England Journal of Medicine on Thursday confirm earlier reports that the virus is a coronavirus. A team led by Christian Drosten at the University of Hamburg, Germany, found a novel strain of the virus, only distantly related to known members of the family. High concentrations of viral RNA were found in sputum. Low concentrations were also found in blood during the acute phase of infection.
Some medical officials, as well as politicians in Hong Kong and Singapore, have suggested that SARS cannot now be eradicated, and has become a permanent fixture in the Far East, and possibly elsewhere.
鈥淲hether it is here to stay in North America I think remains to be seen, but I think we should assume that it may well be,鈥� said Jim Hughes, head of infectious diseases at the CDC.
Journal reference: New England Journal of Medicine (DOI: 10.1056/NEJMoa030781 and DOI: 10.1056/NEJMoa030781)