Sars

The SARS epidemic sent a panic through Asia.

There are seven coronaviruses that can affect people. The common cold is one, as are its more virulent cousins: SARS, severe acute respiratory virus, and MERS, Middle East respiratory virus.

SARS and MERS are examples of two earlier coronaviruses.

How do they treat SARS?

Health officials in China say the recent surge of new SARS cases may be leveling off in Beijing.

Natural epidemics like the Ebola virus or SARS have the power to terrify, but even more chilling is the idea of disease used as a weapon.

City officials have extended a quarantine on people exposed to SARS, including cordoning off a second hospital.

The spokesman for the World Health Organization, Iain Simpson, says there is no conclusive evidence linking the animal, the civet cat, to the SARS outbreak.

He says extra care is necessary in Hong Kong because there is the danger that SARS or a variation of the disease could reemerge.

Using data from the known cases of MERS, the researchers found that, on average, someone with the disease is likeliest to infect at most, only one other person. SARS patients were likely to infect three others. That level of contagiousness made it a pandemic.