Common cold may have spawned killer virus, scientists say

The hunt for the cause of the pneumonia-like illness that has spread global fear narrowed yesterday when two more laboratories said they had isolated the virus responsible.

The hunt for the cause of the pneumonia-like illness that has spread global fear narrowed yesterday when two more laboratories said they had isolated the virus responsible.

Cockroaches were blamed by officials in Hong Kong for the spread of some cases of severe acute respiratory syndrome (Sars). The infection caused 45 new cases and caused two more deaths in Hong Kong yesterday.

Two more areas of the densely populated territory reported clusters of cases, bringing the total to 928 since 12 March with 25 deaths.

The Central Public Health Laboratory in Colindale, north London, said it had found evidence of a hitherto unknown corona virus in samples taken from Sars patients.

"The isolation of this particular type of coronavirus from these patients represents significant progress in finding the cause of Sars," Dr Maria Zambon, who is leading the British team, said in a statement.

Scientists led by Malik Peiris, the head of virology at the University of Hong Kong, reported in The Lancet that the corona virus was now the main suspect.

Ten laboratories around the world have implicated the corona virus in the epidemic and work is going on to identify it and trace its origin. Corona- viruses are thought to be the second most common cause of cold symptoms after rhinoviruses.

Normally in humans coronaviruses produce mild symptoms such as sore throats, coughs, sneezing and headaches. But the new coronavirus appears to be in a different league, producing a severe pneumonia-like illness, a collapse of lung function and death. Scientists are still uncertain whether other viruses might also play a role.

In Hong Kong, 283 cases of the illness have been recorded in one housing estate, Amoy Gardens, and the residents of the blockhit worst have been interned in government-run quarantine camps. Attention has focused on a leaking sewage pipe as a possible vehicle for spread of the disease but no proof has been found.

Doctors are puzzled because coronaviruses can only survive outside the body for two to three hours. Hong Kong's deputy director of health, Leung Pak-yin, said yesterday that cockroaches might have carried infected waste from sewage pipes into flats in Amoy Gardens. If so, the disease could be even harder to contain.

Sars has infected more than 2,600 people and caused more than 100 deaths in 20 countries around the world in the past month. In Britain, the fifth patient with the disease, a man admitted to Addenbrooke's hos- pital, Cambridge at the weekend, was stable yesterday.

Many countries have stepped up efforts to contain the disease. Two Chinese runners have been asked to pull out of Sunday's Rotterdam marathon because of concerns about the spread of the virus, which is believed to have originated in China.

The Singapore government said web-based cameras might be used to enforce home quarantine orders on those who had had close contact with Sars patient. Singapore reported five more cases yesterday, bringing the total to 118 with nine deaths.

In Thailand, Thaksin Shinawatra, the Prime Minister, promised to pay one million baht (£15,000) to the family of anyone who died of Sars. He was trying to demonstrate confidence in the measures taken to curb the disease.

In Guangdong, the southern Chinese province thought to have been the source of the outbreak, Huang Qingdao, the director of the provincial health department, said yesterday that the rate of new infections was slowing and that the disease was "effectively controlled". There were 21 cases in the first week of April compared with 344 in the month of March and 688 in February, he said.