Tears might spread SARS, but analysing samples taken from tear ducts could also help with detecting the virus early, doctors in Singapore said on Monday.
Dr Seng Chee Loon of the National University Hospital in Singapore and his colleagues found the virus in samples taken from tear ducts they analysed from 36 patients suspected of being infected last year.
The highly infectious respiratory illness, severe acute respiratory syndrome (SARS), has affected more than 8,000 people in nearly 30 countries and killed nearly 800, according to the World Health Organisation.
The outbreak, which first emerged in southern China in 2002, was brought under control, but public health experts fear it could re-emerge.
In the Singapore study three of the eight patients who had probable SARS had the virus in their tears. All of them were newly infected. In one patient the virus was only found in the tears.
“This is the first case series reported with the detection of the SARS coronavirus from tears and has important implications for the practice of ophthalmology and medicine,” Loon said in a report in the British Journal of Ophthalmology.
The findings suggest that the virus can be detected and isolated in the early phase of infection and could be an important diagnostic tool because analysing tears is simple and easy.
But it also may mean that the virus could be spread through tears, in addition to droplets from coughs or sneezes, which could pose an additional health hazard for healthcare workers and the general public.
“Ophthalmic practices may need to change as more stringent barrier methods, appropriate quarantine, and isolation measures are vital when managing patients with SARS,” Loon added.
Scientists identified its cause as a new virus from the family of coronaviruses that are responsible for the common cold and a range of animal illnesses.
Loon said he did not find the virus in the tears of other patients whose symptoms started earlier, which could mean sampling tear ducts may provide an early test for the illness.
“As all three positive cases had sampling performed early in the course of their illness, we hypothesise that the secretion of virus in tears occurs only during the early phase of the disease,” said Loon.
“The study also suggests that SARS, like other viruses, can involve the eyes,” he added.
Herpes viruses, chicken pox, Epstein Barr virus, hepatitis C and B, and measles have also been detected in tears.
SOURCE: British Journal of Ophthalmology, July 2004.
Revision date: June 21, 2011
Last revised: by Amalia K. Gagarina, M.S., R.D.