May 6, 2003 -- Outbreaks of mysterious infectious diseases are nothing new. In fact, the world has seen one or two new infections each year for the past decade. So why does the current epidemic of SARS (severe acute respiratory syndrome) matter?
Experts say SARS not only speaks volumes about the current state of the science of infectious disease, but it also serves as a wake-up call about the increasing vulnerability of global public health.
"SARS is not just a blip on the radar screen," says Anthony S. Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (NIAID). "In a very short period of time, it has emerged as a new infectious disease that has likely jumped from animals -- although we're not 100% sure about that yet -- and it became a global public health threat in a matter of weeks."
Fauci says people speak of globalism in political and economic terms, but SARS is an example of the globalism of health in the extreme. "Within the hours of an airplane ride, a disease can become global," Fauci tells WebMD.
He says SARS reminds us that the threat of emerging and reemerging infectious diseases is always present.
Although some recent disease outbreaks, such as the hantavirus and Legionnaire's disease epidemics of the late 20th century, later turned out to be relatively minor in scope and were quickly contained, Fauci says SARS is likely here to stay.
SARS Threat May Never Be Completely Over
Through a combination of sheer luck, advance warning, and good infection control practices, both Fauci and CDC director Julie Gerberding, MD, acknowledge the U.S. has thus far been spared from the worst of SARS. The country has not yet experienced widespread transmission of the disease or had any SARS-related deaths.
"I would reframe luck as good fortune in this case," says Gerberding. "And for us, good fortune in this case comes in the form of a prepared public health and clinical community. But to some extent, we have been fortunate that a particularly contagious patient has not slipped through the cracks."
"Just a single person can set off a cascade of transmission with very serious consequences for the community," says Gerberding.
Gerberding points to the example of Taiwan, where a single SARS-infected traveler is thought to have infected a large number of close contacts and healthcare workers and spurred the epidemic in that country. The ripple effects of similarly effective disease transmitters, known as "superspreaders," continue to be felt in other areas that experienced clusters of SARS outbreaks, such as Hong Kong and Toronto.
That's why Gerberding says SARS will continue to pose a threat to the U.S. as long as the disease is being actively transmitted anywhere in the world.
Speed of SARS Rivaled by Science
At the same time, Fauci says the speed with which researchers were able to isolate and sequence the previously unknown coronavirus that causes SARS demonstrates how far the science of infectious diseases has come. It took years to identify HIV as the causes of AIDS, for example, but now the cause of a newly emerging disease can be sequenced in a matter of days or weeks.
But there is still much work to be done. Tests to screen for SARS quickly and accurately still need to be refined, and research into potential treatments or vaccines is still in the early stages. Laboratories at the U.S. Department of Defense are currently testing all available drugs and even those currently under development by pharmaceutical companies for potential activity against the SARS virus.
Preliminary results show a particular type of antiviral drugs known as interferons, which are commonly used to treat hepatitis C virus infection, might be effective against the SARS virus. But experts say the dosages needed to kill the virus in the test tube may never be feasible in humans. And a vaccine is months if not years away from widespread use.
Lessons of SARS
While the research on SARS is only in its infancy, experts say it's already clear that one of the lasting lessons of SARS may actually be political.
"It teaches us that it's not a good idea for politicians to stonewall about public health threats because you can't fight Mother Nature," says Martin Blaser, MD, chairman of the department of medicine and professor of microbiology at New York University. "The best time to jump on it is early. After it's spread, it's much harder to contain and that's what the situation in China has taught us."
Chinese officials have been criticized for initially withholding information on an outbreak of an atypical pneumonia in the Guangdong province in November 2002. That outbreak is now believed to be the first documented cases of what later became known as SARS.
Fauci says SARS has also prompted a new level international cooperation on both a scientific and political level through the World Health Organization and other international efforts. And he says those lessons will likely pay off in the future in dealing with the next great disease outbreak.
In fact, Gerberding seems to already be taking these lessons to heart. In closing today's briefing on the status of SARS, she urged the public to take precautions against the West Nile virus, because the peak season for disease-carrying mosquitoes is right around the corner.
"Emerging infectious diseases are appearing right and left, and we can't ignore one because we are concentrating on another," says Gerberding.