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• Re: The severe acute respiratory syndrome coronavirus in tears
  Tommy R Tong
  Published on: 14 July 2004

• Published on: 14 July 2004

  Re: The severe acute respiratory syndrome coronavirus in tears

  • Tommy R Tong, Pathologist
  • Other Contributors:
    • Thomas Sik-to Lai

  Dear Editor

  We welcome Loon SC et al's article [1]. Earlier, we published our finding of the SARS CoV in specimens collected by the novel technique of conjunctiva upper respiratory tract irrigation (CURTI), but not in paired nose and throat swabs, very early in the course of the disease [2]. In designing CURTI, we considered safety to medical personnel but also, in finding a method that samples all three portal...

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  Dear Editor

  We welcome Loon SC et al's article [1]. Earlier, we published our finding of the SARS CoV in specimens collected by the novel technique of conjunctiva upper respiratory tract irrigation (CURTI), but not in paired nose and throat swabs, very early in the course of the disease [2]. In designing CURTI, we considered safety to medical personnel but also, in finding a method that samples all three portals of entry for upper respiratory viral pathogens ¡V the eyes, nose and mouth. Loon et al's finding now complements our study by showing that SARS CoV indeed can be found in tears.

  While we agree with their conclusion that the ability to isolate the virus early in the course is important, we do not feel that the eyes are important organs that propagate the virus, other than to ophthalmologists and to unwary close contacts. For instance, the eyes cannot generate infectious aerosol. Rather, we feel that the eyes are important portals of entry and have not been given sufficient attention - witness medical personnel in full personal protection gears and N95 masks but without watertight goggles, and sometimes without splashguards at all.

  We also feel that employing the services of ophthalmologists for the purpose of collecting tear specimens for the diagnosis of SARS is difficult to achieve in most medical environments. On the other hand, our method of CURTI is entirely self-help, deployable to quarantine locations, and avoids unnecessary contact between an infectious source and susceptible individuals.

  The finding of SARS CoV in tear raises several additional questions:

  1. How does the virus end up in the tear? Was it due to direct inoculation at the time of infection to permissive conjunctival epithelial cells, either by hands or aerosols, or was it the result of secretion from a lacrimal gland infected hematogenously? The lacrimal glands are not very different anatomically from the salivary glands. Yet saliva has been shown to be a poor specimen for the laboratory diagnosis of SARS.[3]

  2. Was there any evidence of conjunctivitis, lacrimitis, or evidence of infection of the globe or nasolacrimal sac?

  3. Is there any means or advantage in sampling the nasolacrimal sac, to which the tear drains, and could the nasolacrimal duct system be itself a hideout for the SARS CoV during the incubation period?

  References

  (1) Loon SC, Teoh SC, Oon LL, Se-Thoe SY, Ling AE, Leo YS, Leong HN. The severe acute respiratory syndrome coronavirus in tears. Br J Ophthalmol. 2004 Jul;88(7):861-3.

  (2) 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 Nov;41(11):5352.

  (3) Drosten C, Chiu LL, Panning M, Leong HN, Preiser W, Tam JS, Gunther S, Kramme S, Emmerich P, Ng WL, Schmitz H, Koay ES. Evaluation of Advanced Reverse Transcription-PCR Assays and an Alternative PCR Target Region for Detection of Severe Acute Respiratory Syndrome-Associated Coronavirus. J Clin Microbiol. 2004 May;42(5):2043-7.

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  Conflict of Interest:
  None declared.

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