New diseases pose threat to world health

At least 30 new diseases are expected to appear over the next three decades as a result of environmental disruption, global warming and behavioural change, the Royal Society warned yesterday.

At least 30 new diseases are expected to appear over the next three decades as a result of environmental disruption, global warming and behavioural change, the Royal Society warned yesterday.

The reappearance of Sars (Severe Acute Respiratory syndrome) in China, the lethal pneumonia-like disease that killed 800 people in 27 countries last year, is a signal to the world of the threat from emerging infections, scientists said.

The first new case of Sars since last year's outbreak was confirmed last week in a television journalist from Guangzhou, the southern Chinese city in the province of Guangdong. A second unlinked case was reported to have been confirmed yesterday in a 20-year-old waitress. A third suspect case is being investigated.

International experts meeting at the Royal Society in London yesterday to debate the lessons of Sars were told that the frequency of epidemic outbreaks was increasing.

Professor Tony McMichael, director of the National Centre for Epidemiology and Population Health at the Australian University, Canberra, said: "Sars, Aids, Ebola and Marburgs disease have all emerged in the past 30 to 40 years. There have been 30 new diseases since 1975 and we can expect a similar number in the future."

Most new infections occurred as a result of increased human contact with animals. Aids is believed to have arisen when humans moved into the forests of Africa on logging expeditions and butchered chimpanzees for their meat, Professor McMichael said.

Malik Peiris, professor of microbiology at Hong Kong University and one of the first scientists to identify the Sars virus, said there was an urgent need to monitor viruses that jumped from animals to humans. Many did not cause disease in animals so were not picked up by conventional veterinary checks.

"We were fortunate Sars was a global health problem solved with a global effort. It will not be the last and a global effort to solve future health problems will be very important," he said

Professor Nan Shan Zhong of the Guangzhou Respiratory Disease Research Institute said there were clues that suggested a link between Sars and the civet cat, bred as a delicacy in China.

The virus was highly concentrated in the cats' faeces and the first cases last year occurred in animal traders. Thousands of the cats have been killed in the past week after the Chinese government ordered a cull following the latest cases of Sars and banned their sale in markets.

Raccoon-dogs and other similar animals have been included in the cull.

Professor Zhong said that it would be 20 to 30 days before it became clear whether the cull had curbed the virus but he remained optimistic. "I suppose there will not be another outbreak," he said.