A study led by Dr. Herbert Kaufman, Boyd Professor of Ophthalmology at Louisiana State University Health Sciences Center in New Orleans, published in the January issue of Investigative Ophthalmology & Visual Science, found that 98% of the participants who are healthy individuals with no evidence of any symptoms did in fact shed herpes simplex virus type I (HSV-1) DNA in their tears and saliva at least once during the course of the 30-day study.
The study was undertaken to assess the frequency of shedding of HSV-1 DNA in tears and saliva of asymptomatic individuals.
While not the first, the researchers report that this study uses the most sensitive techniques in a cross-sectional assessment performed to date of the presence of HSV-1 DNA in the eyes and mouths of healthy individuals, in terms of population size and total samples collected.
HSV-1, and to a lesser extent, HSV-2 are known to be the leading causes of virus-induced blindness in the Western world, with approximately 500,000 individuals having herpetic eye disease in the United States. Humans are reservoirs for herpes viruses and shedding in infected individuals when they are asymptomatic is a major factor in the transmission of the virus.
The 50 participants, who were recruited from the general population, ranged in age from 19 to 71. Nineteen were male and 31 female. African-Americans comprised 78% of the participants. The participants were asked to provide a blood sample as well as samples from twice daily swabs of their eyes and mouths for 30 consecutive days. Samples were analyzed using methods including real-time PCR, the gold standard for HSV detection in clinical samples.
Shedding was intermittent, but overall, 49 participants (98%) shed HSV-1 DNA at least once during the study. Thirty-seven participants (74%) had positive blood test results. The percentages of positive results between the eye and mouth swabs were approximately equivalent, but one measure showed higher volume in saliva than in tears. Only one participant did not shed any HSV-1 DNA. Three participants shed HSV-1 DNA in their tears but not their saliva and two had only positive saliva swabs.