Application of Fluorescent Antibody Technique and Plaque Reduction Test for Measuring the Measles Virus Antibody Titers among Selected Children ofMianeh Villages

Measles, a viral exanthema ofchildhood, is the most contagious infection of humans. Measles virus is a member of the genus Morbillivirus ofthe family Paramyxoviridae. Despite the million's lives saved by the global measles vaccination program ofthe World Health Organization (WHO) some 1 million infants and children continue to die each year from measles. In order to reduce the above mentioned figure more than 90% of children having 9 months of age or more must be immunized against measles.It is of great importance to do continuous serum surveys to measure herd immunity to disease. Several serologic tests are used to show the level ofmeasles antibody, and each test has its own advantages and disadvantages.In this study it was attempted to apply indirect immunofluorescent test (IIF), serum neutralization test (SNT), and plaque reduction test (PRT) to detect and measure measles antibodies. One hundred and twenty sera collected from children under the age of 5 living in some villages of Mianeh were tested with the IIF and SNT. Fifty of the sera were also tested using the PRT.To run the tests most of the reagent were used; e.g. fluoresceine-conjugated antihuman rabbit immunoglobulin measles antigen, and purified human IgG were first prepared. Taking the PRT as a gold standard test, the results obtainend from the IIF and SNT were compared with those ofthe PRT. Sensitivity and specificity ofthe IIF were equal to 84% and 67% respectively, whereas they were equal to 97% and 83% for the SNT.