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2、he top right hand corner. Providing it isnt libellous or obscene, it will be posted within seven days. You can retrieve it by clicking on read eLetters on our homepage. The editors will decide as before whether to also publish it in a future paper issue. Tears and conjunctival scrapings for coronavi
3、rus in patients with SARS Severe acute respiratory syndrome (SARS) was first recognised in Guangdong Province in China and later in Hong Kong in March 2003.1Within a matter of weeks, the out- break has evolved to become a global health threat and almost 30 countries have been afflicted with the nove
4、l coronavirus strain (SARS-CoV).2SARS is a highly contagious potentially lethal disease. The main route of transmissionisbyrespiratorydroplets, though the virus has also been isolated in stool and in urine. Tears, being one of the body fluids, may potentially harbour the coronavirus. The presence of
5、 viruses in these body fluids may affect our precaution prac- tices and sites of sampling for diagnostic tests. Case series A prospective interventional case series study was conducted on the identification of the SARS-CoV virus in tear secretions and con- junctival cells of patients with confirmed
6、SARS. Approval was obtained from the ethics committee of the Chinese University of Hong Kong. Consecutive patients with probable SARS in the Prince of Wales Hospital, Hong Kong, during the epidemic period from April to May 2003 were recruited. Other than the routine samples of nasopharyngeal, mouth-
7、 wash and stool, tear swab and conjunctival scraping were taken randomly from one eye of all recruited patients. The tear swab was taken by putting a sterile cottonwool stick into the deep lower fornix of each patients eye after a single drop of topical anaesthetic agent (1% amethocaine eye drops) w
8、as applied. Conjunctival scraping was performed at the lower palpebral con- junctiva with a bent tip of a sterile 23 gauge needle. All ocular samples were collected by a single ophthalmologist with personal protec- tive equipment recommended by the infec- tion control unit of the hospital. Particula
9、r care was taken not to contaminate the samples. The samples were analysed by virus culture and RT-PCR. The SARS-CoV specific primers COR-1 (sense) 59 CAC CGT TTC TAC AGG TTA GCT AAC GA 39 and COR-2 (antisense) 59 AAA TGT TTA CGC AGG TAA GCG TAA AA 39 were used to detect the presence of SARS- CoV RN
10、A.3All the patients were further categorised as confirmed SARS with a sero- conversion or fourfold increase in antibody titre. The antibody against coronavirus was detected by indirect immunofluorescent tech- nique based on Vero cells infected with SARS-CoVisolatedfromapatientwith SARS.3 A total of
11、20 probable SARS patients were recruited and 17 were later confirmed with paired convalescent sera. Among the con- firmed cases, the mean age was 40.5 (SD 8.8) years and 12 (70.6%) were female. They were recruited during the first (n=6, 35.3%), second (n=8, 47.1%), and third (n=3, 17.6%) weeks of th
12、eir diseases. Five (29.4%) of the 17 patients were positive for SARS-CoV by PCR with the samples from nasopharynx or stool (table 1). In all tear and conjunctival scraping samples, no SARS-CoV virus could be detected by RT-PCR or isolated by viral culture. Apart from two patients having mild and sel
13、f limiting conjunctival bleeding after scrapings, no other ophthalmic complication was reported. Comment The routes of transmission of SARS other than respiratory droplets and stool are still enigmatic. In fact, tears have been reported by the World Health Organization to be one of the body fluids t
14、hat might convey the novel SARS coronavirus, though the infectiv- ity or clinical significance is not known.4 The negative findings of SARS-CoV viral genetic material or viable virus in the tear secretion or conjunctival cells of patients with serologicallyconfirmedSARSmayhave several interpretation
15、s. Firstly, RT-PCR test- ing or viral culture is known to be very specificbutlackssensitivity.Peirisand colleaguesreportedthatonly22of44 (50.0%)nasopharyngealaspiratesamples and 10 of 18 (55.6%) faecal samples from patients confirmed with SARS had corona- virus genetic material detected by RT-PCR.5
16、So negative test results can be false negative and do not exclude the presence of the virus. Sensitivity can be increased if multiple speci- mens are tested. Secondly, it is possible that the virus and its genetic material were only present for a brief period of the disease, and the samples were not collected at the right time. Thirdly, the virus might not be present in tears at all. Thelimitations ofth
