Herpes simplex keratitis in South India: Clinico-virological correlation

Purpose: A retrospective cross-section study to analyze the prevalence of h erpes simplex virus-induced keratitis (HSK) among 3,000 patients attending a corneal clinic in South India between 1995 and 1997, and to evaluate labo ratory techniques for detecting HSK, Methods: The clinico-virological correlation was studied using herpes simpl ex virus (HSV) isolation on the Vero cell line, HSV-specific antigen detect ion by indirect immunofluorescence (IF) microscopy, and serum anti-HSV IgG quantitation, IgM estimation, and tear secretory IgA (sIgA) detection by EL ISA. Observations: HSK had a prevalence of 7.8% (234 patients) in this study. A virological correlation could be obtained in 44.4% of the cases that had ep ithelial manifestations and in 14.8% of the cases that had only stromal dis ease. In 161 cases where both culture and IF microscopy were used, IF detec ted 27 cases (26.8%) more than cell culture. The difference in sensitivity between cell culture and IF was found to be statistically significant (McNe mar's test, P < .05). An elevation in IgG titer was seen in 17 (30.4%) case s. IgM was detected in only 2 cases of the 62 (3.2%) analyzed. Of the 138 c ases analyzed, sIgA was positive in 28 (20.3%) cases. A proved diagnosis co uld be made in 58% of cases when the specimen was collected during the firs t week after disease onset, and in only 5% when the time interval increased to 4 weeks. Conclusions: HSV antigen detection by indirect IF is a rapid and sensitive diagnostic tool for HSK. Tear secretory IgA (sIgA) is a specific marker for acute herpetic keratitis, and the detection of HSV-specific tear sIgA is a valuable adjunct to virus isolation and antigen detection in the laborator y diagnosis of HSK. For a successful diagnosis, the specimen should be coll ected as soon as possible after HSK onset. Jpn J Ophthalmol 1999;43:303-307 . (C) 1999 Japanese Ophthalmological Society.