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Letter
SARS-CoV Sampling from 3 Portals
Tommy R. Tong*
*Princess Margaret Hospital, Hong Kong, Special Administrative Region,
China
Suggested
citation for this article
To the Editor: Wang et al. detected severe acute respiratory syndrome–associated
coronavirus (SARS-CoV) from throat wash and saliva specimens and suggested
that these specimens have advantages over other specimens, including ease
of procurement and safety for medical personnel (1).
The virus has been detected with variable success from nasopharyngeal
aspirates, nose and throat swabs, and tears (2,3). Advocates
of all of these sampling methods emphasize the need for early diagnosis
of SARS. The probability for nosocomial transmission to healthcare workers
when they obtain specimens from patients has not been adequately addressed.
In a study of outbreak control for SARS, Chowell et al. suggest "…
the strong sensitivity of R0 to the transmission rate
β indicates that efforts in finding intervention strategies that
manage to systematically lower the contact rate of persons of all age
groups promise an effective means for lowering R0"
(4).
An important component of a comprehensive strategy to lower the contact
rate is improving the safety measures recommended for clinical specimen
collection by healthcare workers. Recognizing the importance of obtaining
multiple specimens and the difficulties associated with obtaining samples
from the 3 usual portals of entry, we devised and tested a novel method
of specimen collection, conjunctiva–upper respiratory tract irrigation
(5). We coupled our specimen collection method with detailed
written instructions to enable the patients themselves to perform the
entire procedures. Almost all other specimen collection methods require
assistance from healthcare workers or have other limitations, such as
inability to sample all 3 portals. The method is not perfect because some
persons have difficulty performing the procedure; however, self-instillation
of the irrigation into the nostrils, with or without the addition of a
throat wash or saliva, is likely to improve the success rate. The data
supplied by Loon et al. (3) and Wang et al. (1)
confirm that collecting specimens by a method that involves minimal contact
between a possible source of infection and susceptible persons is desirable.
The author has shares
of a company that owns a patent-pending conjunctiva-upper respiratory
tract irrigation system.
References
- Wang WK, Chen SY, Liu IJ, Chen YC, Chen HL, Yang CF,
et al. Detection
of SARS-associated coronavirus in throat wash and saliva in early diagnosis.
Emerg Infect Dis. 2004;10:1213–9.
- Chan PK, To WK, Ng KC, Lam RK, Ng TK, Chan RC, et al. Laboratory
diagnosis of SARS. Emerg Infect Dis. 2004;10:825–31.
- Loon SC, Teoh SC, Oon LL, Se-Thoe SY, Ling AE, Leo YS, et al. The
severe acute respiratory syndrome coronavirus in tears. Br J Ophthalmol.
2004;88:861–3.
- Chowell G, Castillo-Chavez C, Fenimore PW, Kribs-Zaleta CM, Arriola
L, Hyman JM. Model
parameters and outbreak control for SARS. Emerg Infect Dis. 2004;10:1258–63.
- Tong TR, Lam BH, Ng TK, Lai ST, Tong MK, Chau TN. Conjunctiva–upper
respiratory tract irrigation for early diagnosis of severe acute respiratory
syndrome. J Clin Microbiol. 2003;41:5352.
Suggested citation
for this article:
Tong TR. SARS-CoV sampling
from 3 portals [letter]. Emerg Infect Dis [serial on the Internet]. 2005
Jan [date cited]. Available from http://www.cdc.gov/ncidod/EID/vol11no01/04-0645.htm
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