The worldwide death toll taken by severe acute respiratory syndrome (SARS) reached 144 Tuesday, with 56 killed in Hong Kong - nine more dying in a single 24-hour span, the sharpest rise since the disease broke out last month.
As medical researchers scrambled to find a way to fight the pneumonia-like virus that has infected thousands of people in 21 countries, laboratories in the U.S. and Canada came up with a sequence of the suspected virus almost simultaneously.
"It's beginning to look more and more like this is it," said Caroline Astell, projects leader for the Michael Smith Genome Sciences Centre in Vancouver, British Columbia, referring to the new type of coronavirus that is believed to be the culprit in SARS.
The center was first to sequence the virus, disclosing the news Saturday. After getting one-millionth of a gram of purified viral genetic material from the National Microbiology Lab in Winnipeg, relayed by the British Columbia Centre for Disease Control, the center said, scientists worked "around the clock" to complete the sequence, news of which was disclosed at 4 a.m.
On Monday, the Centers for Disease Control in Atlanta said scientists there, too, had completed a sequence.
"At this point, it's not 100 percent certain this virus is the cause of SARS," Astell cautioned, but the evidence is strong.
"We've come up with essentially the same virus," she told BioWorld Today. "Ours was from Toronto and [the CDC's] was from Hanoi. It passed through a lot of individuals and it's the same thing."
Sequencing about 29,000 nucleotides, the two labs came up with results that differed by only 10 base pairs. The sequences were not similar enough to the version of coronavirus found in animals to determine the disease's origin, but further tests of the new virus in animals are under way at other centers to discover whether experimental primates' symptoms are similar to those seen in humans.
Meanwhile, 193 SARS cases have been reported in the U.S., none of them fatal. The CDC said procedures have slowed the spread of the disease here, in Taiwan, and in Canada, but it still is not controlled in Hong Kong, China and Singapore.
Astell noted the center, which published the sequence on its website, www.bcgsc.bc.ca, is "not a virology institute or a company - our main focus is cancer research." Anyone is free to use the sequence, she added, and "we're collaborating with two of them," those being National Microbiology Lab in Winnipeg, relayed by the British Columbia Centre for Disease Control.
Having the sequence is likely to help in the development of a much-needed vaccine and more, she said.
"My understanding is that there are general PCR primers for the coronavirus, but [having the new sequence] is going to allow people to develop diagnostic tools that are highly specific," she said.
Late last week, Hamburg, Germany-based artus GmbH declared its plans to launch Monday a SARS detection assay, the RealArt HPA-Coronavirus RT PCR Reagents kit, in the U.S. and Malaysia.
The company said the diagnostic, which provides results within two hours, was devised in cooperation with the Bernhard Nocht Institute for Tropical Medicine in Hamburg.
As a treatment for SARS, initial reports seemed to suggest the antiviral ribavarin might be useful. ICN Pharmaceuticals Inc., of Costa Mesa, Calif., said early this month it is cooperating with the World Health Organization in Geneva, the CDC, Health Canada and the FDA, which contacted the company regarding availability of the drug.
A spokesman for ICN told BioWorld Today the company had no comment beyond what already has been said, and the CDC has said more study of ribavarin has yielded less than promising results.