Prevalence of Herpes Simplex Virustype-1, 2 and Varicella Zoster Virus (VZV) in Eye Infection

Herpes simplex virus (HSV) is a common cause of corneal disease and is the leading infectious cause of corneal blindness among developed nations. This study is aimed to provide an estimation of the incidence of Herpes Simplex Virustype-1, 2(HSV1, 2) and Varicella Zoster Virus (VZV) in tears and swab from eye infection by polymerase chain reaction (PCR) in eye disease in a suspected community.
Fifty subjects without signs of ocular herpetic disease enrolled in the study. Serum samples from all subjects were tested for HSV IgG antibodies by enzymelinked immunosorbent assay (ELISA). Subjects were instructed to collect tear samples by touching the inner surface of the lower eyelid with an individually wrapped, sterile cotton swab and to place the swab immediately into labeled sterile tubes. Swabs were kept at 4°C until processed. Nucleic acid was extracted from the samples and PCR-amplified for HSV DNA.
Among 50 samples, 3 samples were refused because internal controls were negative. HSV infection was established in 10% (5 out of 50) of all patients. The prevalence of HSV infection in patients with no clinical suspicion of herpetic keratitis was 6%. Histopathologic evaluation revealed that among samples with positive PCR results, 100% had evidence of inflammation, 55% had giant cells, 39% had necrosis, 59% had vascularization, 67 % had ulcer and 100% of them had inclusion bodies.
Because some of the patients with no clinical suspicion of herpes infection were found positive, we suggest that HSV to be considered as one of the underlying etiologies in any patient with corneal scar and keratitis. Therefore, performing further diagnostic methods, including PCR and histopathology, is mandatory to clearly understand the infection.