THURSDAY, April 10, 2003 (HealthDayNews) -- Just as experts have suspected, a new coronavirus is probably behind the deadly respiratory illness known as SARS, several international research teams report.
Three studies rushed into publication in the last two days have zeroed in what is being called a "novel" form of coronavirus, which until now had never caused more than mild illness in humans.
Hong Kong scientists came to that conclusion after studying 50 patients with the disease and finding evidence of the viral activity in 90 percent of them.
The report was rushed to early online publication in The Lancet, along with a commentary from two U.S. experts and guidelines on managing the deadly disease, which begins with a fever of greater than 100.4 degrees and can progress quickly to breathing difficulties so severe that mechanical ventilation is required.
But U.S. health officials cautioned Thursday that confirmation of the finding is still needed. Before saying for sure that a coronavirus causes SARS, two more steps need to be done, Dr. Julie Gerberding, director of the U.S. Centers for Disease Control and Prevention (CDC), told a news conference. "We need to demonstrate the presence of coronavirus in affected tissue," such as the lung, and "we must have an animal model," she says.
At the telebriefing, Gerberding also announced that the CDC will post enhanced guidelines for contacts of SARS patients, covering what schools and workplaces should do to help containment efforts. She also urged people not to stigmatize Asian residents, as has been reported in some communities. "This is not a disease in any way related to being Asian," she says.
As of Thursday, the number of reported SARS cases totals 2,722 in 17 countries, with 111 deaths, according to the World Health Organization (WHO). The United States has 166 suspected cases in 30 states, the CDC says. The bulk of the global cases are concentrated in Southeast Asia, where SARS is believed to have originated in China's Guangdong province last November.
[The New York Times reported on Thursday that a senior retired military physician in China accused the country's health ministry of lying about the number of people hospitalized with SARS in Beijing, noting the number in military hospitals alone could be "up to 100."
[And the World Health Organization warned on Thursday that many Beijing hospitals were not making daily reports on SARS cases and authorities were not systematically tracing people who had contact with those infected.}
In the Lancet report, Malik Peiris of the University of Hong Kong and his colleagues report they first identified a new type of coronavirus from two patients with SARS and then found evidence of the same virus activity in 90 percent of the 50 patients they studied.
They then compared those results with 40 control patients with no evidence of SARS and did not find any of the coronavirus activity in them.
The new coronavirus is not one of two known human forms that can trigger the common cold or diarrhea, Peiris' team says. Nor is it identical to the recognized coronaviruses in animals, lending credence to the idea that the SARS virus is brand new or as yet unrecognized and that it may have originated in animals.
Among the many unanswered questions, the researchers add, is whether the virus acts alone or whether another virus also invades the body and speeds progression of the disease.
Another team, writing in the May 15 issue of The New England Journal of Medicine, also accuses this bug of causing the disease and suggests naming it after one of its victims. Dr. Carlo Urbani, a WHO expert on communicable diseases and a member of the team that wrote the article, died of SARS on March 29. He had contracted the disease in Vietnam, where he was treating an American businessman, who also died. The team says the virus should be named "Urbani SARS-associated coronavirus."
A third team of virologists from France, Germany and the Netherlands, writing in the same issue of The New England Journal of Medicine, also reached the conclusion that they were dealing with a new virus.
The journals decided to release the articles early because experts are in the midst of dealing with the SARS crisis.
While the virus is thought to be mainly spread by "droplets" -- an infected person coughs or sneezes and spreads the virus to those nearby -- the U.S. Centers for Disease Control and Prevention hasn't ruled out airborne transmission or the possibility that objects that become contaminated could spread the disease, because coronaviruses can live on surfaces for several hours.
The Hong Kong team now adds one more possibility -- fecal-oral transmission, since the virus may be shed in the feces. Many viruses and bacteria are spread in this way, such as in day-care settings when hand washing practices are poor or in restaurants if food handlers don't wash their hands properly.
One notable strong point of the study is the use of control patients, says Dr. Ann R. Falsey, an associate professor of medicine at the University of Rochester School of Medicine and Dentistry and co-author of an accompanying commentary in the journal.
Still, puzzles remain, Falsey says: "The problem with this is they have just identified the virus and have only sequenced a small part. They might be amplifying part of the gene that's not the most effective to use [for study]."
Meanwhile, the race is on to find an effective treatment. Researchers at the U.S. Army Medical Research Institute for Infectious Disease at Fort Detrick, Md., and at the University of Virginia, among others, will test drugs already on the market and those in development, planning to look at 2,000 possibilities, according to the Associated Press.
Among the possibilities: combining ribivarin, an anti-viral used to treat a respiratory virus in infants, with steroids to calm down the immune system. Some experts are pessimistic it will work. But finding an existing drug that can zap the SARS virus would save five years or more -- the minimum time most experts say is needed to develop a drug from scratch.
More information
For updated information on SARS, visit the World Health Organization or the U.S. Centers for Disease Control and Prevention. For the latest on exposure guidelines, click here.
