In Hong Kong today, health officials reported five more deaths from SARS -- Severe Acute Respiratory Syndrome. They say they are considering stricter travel curbs to limit the spread of the disease, which has now infected more than 3,400 people in 22 countries. As David Cohler reports, the World Health Organization told Mainland China today it, too, must broaden its efforts.

The World Health Organization believes the SARS outbreak originated in China's Guangdong province, and is being spread by air travelers. It says China has failed to report all its cases, and the capital, Beijing, could have several times the officially announced number. Henk Bekedam is the organization's representative in Beijing.

[Henk Bekedam, WHO rep. in Beijing]
"The problem is that the military hospitals do not report -- and I think that's an issue that very clearly, very clearly, is now being advised by WHO that needs to be changed."

As in many countries, the Chinese armed forces have their own network of hospitals, clinics, and medical staff. The WHO says China has indicated its willingness to count SARS cases among military personnel -- but must not delay any longer.

[Henk Bekedam, WHO rep. in Beijing]
"This time there's not much time to have a learning process -- because we know that SARS is spreading."

Scientists believe that SARS is caused by a new form of the coronavirus. Researchers at the University of Hong Kong say a new genetic sequencing of the virus proves that it originated in animals, then spread to humans. But they say the virus is new to science, and the specific mechanism of transmission is still a mystery. While researchers seek to unlock that mechanism, Asian countries are taking ever stricter measures to control the disease?s spread. At airports, bus terminals, train stations, and on the streets -- people are wearing masks. And squadrons of masked workers spray disinfectant -- not quite sure yet how effective it is.