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Letter
Mild Severe Acute Respiratory
Syndrome
Gang Li,* Zhixin Zhao,* Lubiao Chen,* and Yihua Zhou*
*Sun Yat Sen University, Guangzhou, Guangdong Province, China
Suggested citation
for this article:
Li G, Zhao ZX, Chen LB, Zhou YH. Mild severe acute respiratory syndrome.
Emerg Infect Dis [serial online] 2003 Sept [date cited]. Available
from: URL: http://www.cdc.gov/ncidod/EID/vol9no9/03-0461.htm
To the Editor: Severe acute respiratory syndrome (SARS) is a recently
recognized infectious disease caused by a novel human coronavirus (SARS-CoV)
(1). The first case of SARS, diagnosed as communicable
atypical pneumonia, occurred in Guangdong Province, China, in November
2002. Thousands of patients with SARS have been reported in over 30 countries
and districts since February 2003.
SARS is clinically characterized by fever, dry cough, myalgia, dyspnea,
lymphopenia, and abnormal chest radiograph results (1–3).
According to the World Health Organization (WHO) (4),
the criteria to define a suspected case of SARS include fever (>38°C),
respiratory symptoms, and possible exposure during 10 days before the
onset of symptoms; a probable case is defined as a suspected case with
chest radiographic findings of pneumonia and other positive evidence.
Although most reported patients with SARS met the WHO criteria, we found
two SARS case-patients who did not exhibit typical clinical features.
Case 1 was in a 28-year-old physician. He had close contact with three
SARS patients on February 1, 2003. After 10 days, he had mild myalgia
and malaise with a fever of 37.3°C. He had no cough and no other symptoms.
Leukocyte and lymphocyte counts were normal. The chest radiograph showed
no abnormalities. He did not receive any treatment except rest at home.
His symptoms disappeared after 2 days. He completely recovered and returned
to work 4 days after onset of symptoms. After 12 weeks, his serum was
positive for immunoglobulin (Ig) G against SARS-CoV in an indirect enzyme-linked
immunosorbent assay (ELISA) with inactivated intact SARS-CoV as the coated
antigen.
Case 2 was in a 13-year-old boy whose mother had been confirmed to have
SARS on February 4, 2003. Fever developed in the boy 20 days after his
mother’s onset of the disease. He did not come into contact with other
confirmed SARS patients during this period. He had a mild headache and
diarrhea with a fever from 37.2°C to 37.8°C for 3 days. No other symptoms
and signs developed, and a chest radiograph showed no abnormalities. He
completely recovered after 5 days. After 12 weeks, his serum was positive
for IgG against SARS-CoV, detected with an ELISA.
In both case-patients, SARS had been initially excluded in spite of their
close contacts with SARS patients because their symptoms could be explained
as a common cold, and no specific diagnostic approaches were considered
when they were sick since the causative agent of SARS was not identified
until March 2003 (5). However, their serum specimens
were positive for IgG against SARS-CoV by ELISA. Those results strongly
indicate that both patients had been infected with SARS-CoV, although
their signs and symptoms did not meet the criteria for the SARS case definition.
Mild SARS-CoV infection may not easily be defined clinically, and such
patients may potentially spread the disease if they are not isolated.
References
- Peiris
JSM, Lai ST, Poon LLM, Guan Y, Yam LY, Lim W, et al. Coronavirus as
a possible cause of severe acute respiratory syndrome. Lancet 2003;361:1319–25.
- Tsang
KW, Ho PL, Ooi GC, Yee WK, Wang T, Chan-Yeumg M, et al. A cluster of
cases of severe acute respiratory syndrome in Hong Kong. N Engl
J Med 2003;348:1977–85.
- Booth
CM, Matukas LM, Tomlinson GA, Rachlis AR, Rose DB, Dwosh HA, et al.
Clinical features and short-term outcomes of 144 patients with SARS
in the greater Toronto area. JAMA 2003;289:2801–9.
- World Health Organization. Case definitions for surveillance of severe
acute respiratory syndrome (SARS). (Revised 1 May 2003). [Accessed June
6, 2003] Available from: URL: http://www.who.int/csr/sars/casedefinition/en/
- Stohr K. A multicentre collaboration to investigate the cause of severe
acute respiratory syndrome. Lancet 2003; 341:1730–3.
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