Sudden death was the common fear among residents of two cities over the weekend. And the source of the rumors in both cases was information technology; SMS to be more precise.

In fact, many Beijingers who had eaten pork for lunch or dinner, and not many Chinese meals are without pork, suffered a psychosomatic attack. They complained of an upset stomach or an imaginary pain after receiving an SMS from friends or relatives.

The virus was alleged to cause pyogenic encephalitis that destructs the brain, filling its cavities with pus.

Such was the fear that presidents of major hospitals held an emergency meeting to scotch the rumors.

In Shanghai, the paranoia was different. Some Hollywood fortune-teller was alleged to have sent e-mails, which were posted on online forums, saying a big earthquake and tsunami were about to hit the coastal city.

Though doctors, as in Beijing, and some other people across the two cities tried to calm down the residents, it was the authorities' prompt denial that restored order.

In Beijing, Zhao Chunhui, deputy head of the municipal health bureau, told Xinhua on Saturday: "Pork sold in Beijing has to meet strict standards. It's perfectly fit for human consumption. The rumors are nothing but lies."

An unidentified official of Shanghai's seismological bureau said major earthquakes and tsunamis cannot hit the city because of its geological features.

He told the local Wenhui Daily: "Nine tsunamis have been recorded in the history, and none of them caused great damage to the coastal regions. And their impact on Shanghai has been minimal."

Netizens praised the authorities for their timely response in both the cities, with experts saying that they should react similarly to all events that caused public panic.

Rumors gain momentum if trusted organizations don't come up with a satisfactory explanation promptly, said Meng Wei, researcher at the Institute of Journalism and Communication affiliated to the Chinese Academy of Social Sciences, yesterday.

In such an event, the authorities should communicate with traditional media sources such as newspapers and television channels, which are more trusted by the people than the Internet, he said.