Severe Acute Respiratory Syndrome (SARS) Update: Monday, March 31, 2003
Craig Sterritt, Editor, Medscape Infectious Diseases
Today’s Leading News
On Saturday, Centers for Disease Control and Prevention (CDC) Director Julie L. Gerberding, MD, expressed worry that new developments in the epidemiology of severe acute respiratory syndrome (SARS) pointed to what could become “a much larger” epidemic. After reiterating “that the disease is still primarily limited to travelers…and to [those who have had] close contact with SARS patients,” she said U.S. and international health officials were “concerned about the possibility of airborne transmission across broader areas and also the possibility that objects that become contaminated in the environment could serve as modes of spread. “Coronaviruses can survive in the environment for up to two or three hours,” she added, “and so it’s possible that a contaminated object could serve as a vehicle for transfer to someone else.” Although not confirmed as the single cause of SARS, a coronavirus is the leading suspect agent at this time. Dr. Gerberding’s statements coincided with a Hong Kong report that SARS had been transmitted to scores of people in a single apartment complex after a single resident visited a hospitalized relative with SARS. Hong Kong reported more than 100 new SARS cases over the weekend. On Saturday, the World Health Organization (WHO) announced the death of Dr. Carlo Urbani, who first identified the SARS outbreak. Dr Urbani had acquired the disease in the course of his investigations.
Epidemiology: As of March 29, the WHO cumulative tallies of suspected SARS cases and deaths were 1,550 and 54, respectively. On March 29, the CDC reported a total of 62 suspected U.S. cases in 22 states, up from 51 cases on March 27. The number of cases reported by Health Canada has increased from 37 to 98. The new figure includes both suspected and probable cases, whereas the earlier count included probable cases only.
Etiology: A new coronavirus remains the prime suspect in the search for the cause of SARS. Dr. Gerberding stated last week that viruses detected so far did not appear to be a known coronavirus. “We know from sequencing pieces of the virus DNA that it is not identical to the coronaviruses that we have seen in the past. This may very well be a new or emerging coronavirus infection, but it is very premature to assign a cause.”
Diagnosis, Treatment, Outcomes: Scientists at the University of Hong Kong announced on March 27 that they had developed a diagnostic test to rapidly identify SARS cases. The test is based on polymerase chain reaction (PCR) technology. So far, test results in confirmed SARS cases have been consistently positive, while healthy controls have consistently tested negative. Another test, an immunofluorescence assay, is also in development.
In a “virtual grand rounds” on clinical features and treatment of SARS organized by WHO last week, clinicians managing SARS patients described disease features at presentation, treatment, progression, prognostic indicators, and discharge criteria. There was general consensus that no therapy in particular demonstrated any particular effectiveness. According to a summary of the proceedings, participating clinicians agreed “that a subset of SARS patients, perhaps 10 percent, decline and need mechanical assistance to breathe. These people often have other illnesses that complicate their care. In this group, mortality is high.” According to the summary, however, the majority of patients show improvement in signs and symptoms at day 6 or 7.
Regarding treatment, the summary concluded that: “Numerous antibiotic therapies have been tried to date with little clear effect. Ribavirin with or without use of steroids has been used in an increasing number of patients. But in the absence of clinical indicators, its effectiveness has not been proven. Currently the most appropriate management measures are general supportive therapy, insuring the person is hydrated and treated for subsequent infections.”
Summary of Events to Date
On March 15, 2003, WHO issued a global alert of a multicountry outbreak of SARS, an atypical pneumonia of as yet unidentified etiology. According to WHO, the syndrome was first recognized on February 26, 2003, in Hanoi, Vietnam. According to WHO, as of March 29, 2003, SARS cases have been reported in Canada, China, France, Germany, Hong Kong, Indonesia, Italy, Ireland, Romania, Singapore, Switzerland, Taiwan, Thailand, United Kingdom, United States, and Vietnam. A total of 1,550 cases and 54 deaths have been reported to date. SARS appears to be transmitted by close contact only, most probably via airborne droplets; the majority of new cases have been reported in healthcare workers and family members of affected persons. Evidence of community spread of the disease is emerging, however.
On March 24, the CDC announced that a new coronavirus is the prime suspect in the search for the cause of SARS. Confirmation of this is pending.
On March 26, Chinese authorities officially reported a total of 792 SARS cases and 31 deaths that occurred in 7 cities of Guangdong Province between November 16, 2002, and February 28, 2003. As of March 29, WHO is reporting a total of 806 suspected SARS cases and 34 deaths in mainland China.
Health officials in Singapore have quarantined 861 people with flu-like symptoms and have closed all schools until April 6. A total of 89 SARS cases and 2 deaths have been reported there. More than 1,000 people were quarantined and schools were ordered closed in Hong Kong on March 27. This followed the identification of 51new SARS cases and a warning by a top health official that SARS was spreading among the general public.
Scientists at the University of Hong Kong announced on March 27 that they have developed a diagnostic test to rapidly identify cases of SARS. The researchers also announced that they had confirmed a coronavirus as the cause of SARS, and recommended that SARS, a provisional name for the disease, be retermed “coronavirus pneumonia” or CVP.
On March 29, Hong Kong health officials reported that SARS had been transmitted to 78 people in a single apartment complex after a single resident visited a hospitalized relative with SARS.
Source: Medscape Medical News