25 March 2003
Alternate Theories Emerge on Cause of Fast-Spreading Flu
(Health officials express confidence in effective containment of
illness) (900)
By Charlene Porter
Washington File Staff Writer
Washington -- An international research collaboration that
participants describe as "unprecedented" has produced several
alternate hypotheses on the cause of a previously unknown flu-like
disease. The head of the U.S. Centers for Disease Control and
Prevention (CDC) announced in a March 24 news briefing at the agency's
Atlanta, Georgia, headquarters that a coronavirus -- related to the
virus causing the common cold -- has emerged as a likely cause of the
illness.
Other international teams previously identified a paramyxovirus -- a
cause of measles and mumps -- as the suspected agent behind a disease
that begins with a high fever and respiratory symptoms such as a cough
or difficulty in breathing. What is causing real concern in medical
circles is the way the illness, Severe Acute Respiratory Syndrome
(SARS), can rapidly worsen to become a form of sometimes-fatal
pneumonia.
The World Health Organization (WHO) reports 17 deaths from the illness
as of March 25. In frequently updated reports, WHO shows that the
number of probable or suspected cases of SARS worldwide rose from 456
on March 24 to 487 on March 25.
The WHO count on SARS includes cases reported on February 1 or later,
so does not include more than 300 cases in a similar disease outbreak
reported in China's Guangdong province beginning last November. A WHO
team is now working with Chinese health authorities to determine
whether there is a connection in all these cases.
CDC Director Julie Gerberding announced her agency's detection of the
coronavirus in patient specimens analyzed by U.S. researchers, at the
same time expressing respect for different findings being reported by
"world class" laboratories elsewhere.
"Right now, for us, this is a hypothesis. It is our leading hypothesis
based on careful science," Gerberding said March 24. "But there are a
lot of other potential explanations for what we're finding here, and
we are exercising caution and not being dogmatic that we have the
answer here."
Gerberding also noted that laboratories in Europe, Asia and North
America are conducting their analyses using specimens from different
SARS patients, taken at different stages of their illnesses. That fact
could account for the discovery of dissimilar findings from the
research teams.
As the medical detective work unfolds on different continents, WHO
officials said in a briefing March 25 in Geneva that several
hypotheses can be drawn from the various findings. Dr. Klaus Stohr
with WHO's Department of Communicable Disease Surveillance and
Response said either corona viruses or paramoxy viruses of previously
unknown types might be causing SARS.
"The third hypothesis ... is that these two pathogens have to come
together to cause this very severe outbreak," said Stohr. A fourth
idea presented at the Geneva briefing is that the occurrence of the
two viruses could be by chance alone and not related.
The disease has appeared in 13 countries, but the Hong Kong Special
Administrative Region of China is the most severely affected area,
reporting 286 cases and 10 deaths. Other hard-hit nations are
Singapore with 65 cases and Vietnam with 58 cases.
WHO issued a global advisory about SARS 10 days ago, advising
travelers, national health authorities and medical practitioners to be
alert for the signs of the disease. At the WHO briefing, officials
said the fact that outbreaks have not occurred beyond these several
areas in Asia is a sign that the medical officials have been
successful in preventing widespread export of the disease.
In the United States alone, authorities have issued 62,000 cards to
passengers disembarking from international flights and ships, CDC
briefers said. The cards warn passengers about the need to seek
medical attention if they show any of the symptoms and have been
traveling in the affected regions.
Gerberding said all of the 39 suspected cases in the United States fit
the pattern of disease transmission that was suspected early on.
"Thirty-two out of 39 of these individuals have traveled to parts of
the world where cases are prominent. The others are either health care
personnel or close family members who have been in direct contact with
a suspect case. So we are not seeing spread in the community at this
point in time."
The search for the cause of SARS is keeping medical researchers at
work around the clock, but Gerberding also expressed compassion for
those who are sick and their families. Since they don't know the virus
causing the disease, doctors can't advise a particular treatment to
attack it, she said, but instead are treating the pneumonia that has
been the worst symptom.
"The patients are in good hands and receiving good medical care,"
Gerberding said. "The fact that many of them are improving both here
domestically and internationally suggests that the majority of people
will be able to survive this illness if they are in good medical care,
and we are optimistic that will be the case for most people."
Further, Gerberding said, medical experts at the Department of Defense
are joining the collaborative effort against SARS by testing various
anti-viral agents in order to identify the most effective drugs for
treating the disease.
WHO officials said the mortality rate for cases worldwide so far is
four percent, which they consider quite serious. "We want zero
mortality rate," said WHO's Executive Director of Communicable
Diseases Dr. David Heymann.
(The Washington File is a product of the Office of International
Information Programs, U.S. Department of State. Web site:
http://usinfo.state.gov)
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