title: Herpes simplex keratitis in South India: clinico-virological correlation.
abstract: OBJECTIVE
  A retrospective cross-section study to analyze the prevalence of herpes simplex virus-induced keratitis (HSK) among 3,000 patients attending a corneal clinic in South India between 1995 and 1997, and to evaluate laboratory techniques for detecting HSK.
  
  
  METHODS
  The clinico-virological correlation was studied using herpes simplex virus (HSV) isolation on the Vero cell line, HSV-specific antigen detection by indirect immunofluorescence (IF) microscopy, and serum anti-HSV IgG quantitation, IgM estimation, and tear secretory IgA (sIgA) detection by ELISA.
  
  
  METHODS
  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 epithelial manifestations and in 14.8% of the cases that had only stromal disease. In 161 cases where both culture and IF microscopy were used, IF detected 27 cases (26.8%) more than cell culture. The difference in sensitivity between cell culture and IF was found to be statistically significant (McNemar's test, P < .05). An elevation in IgG titer was seen in 17 (30.4%) cases. IgM was detected in only 2 cases of the 62 (3.2%) analyzed. Of the 138 cases analyzed, sIgA was positive in 28 (20.3%) cases. A proved diagnosis could be made in 58% of cases when the specimen was collected during the first 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 laboratory diagnosis of HSK. For a successful diagnosis, the specimen should be collected as soon as possible after HSK onset.
authors.affiliation: Department of Microbiology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai, India.
authors.forename: N P
authors.initials: NP
authors.lastname: Pramod
authors.forename: P
authors.initials: P
authors.lastname: Rajendran
authors.forename: K A
authors.initials: KA
authors.lastname: Kannan
authors.forename: S P
authors.initials: SP
authors.lastname: Thyagarajan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D000956:Antigens, Viral / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D002522:Chlorocebus aethiops; D003315:Cornea / Q000821:virology*; D003430:Cross-Sectional Studies; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D018259:Herpesvirus 1, Human / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D007194:India / Q000453:epidemiology; D007223:Infant; D016849:Keratitis, Herpetic / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D013666:Tears / Q000276:immunology; D014709:Vero Cells / Q000382:microbiology; D014776:Virus Cultivation
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D007071:Immunoglobulin A, Secretory