A RAPID CULTURE ASSAY FOR EXAMINING MEASLES-VIRUS INFECTIONS FROM URINE SPECIMENS

Background: Large numbers of measles virus (MV) specimens are processe d in our laboratory each year as part of a molecular epidemiological s tudy of MV in South Africa. The development of a sensitive, rapid viru s isolation system is needed to cope with the number of specimens proc essed. Objectives: A comparison was made of centrifugation-enhanced sh ell vial culture and standard tissue culture using B95a cells for the isolation of MV from throat swabs and urine. Study design: The rapid m ethod was initially evaluated using Schwarz vaccine virus and then com pared to standard culture using throat swab specimens. Results: The sh ell vial assay proved to be ten times more sensitive than standard cul ture in the initial evaluation. Of 43 throat swab specimens, 37 (86%) were positive and 6 (14%) negative in standard culture using B95a cell s. The specimens were removed after adsorption in standard culture, fr ozen and then used in the shell vial assay. It was found that 16/27 we re positive in the shell vial assay (24 of these 27 being positive in standard culture,) and 8 negative and 8 specimens gave an indeterminat e result. For the 45 urine specimens used in the shell vial assay, 71% were positive, 11% negative and 18% gave an indeterminate result, due to too few cells being present for antigen determination by indirect fluorescent antibody assay. Results were obtained in 4 days, as oppose d to the average of 14 days for confirmed isolation in standard cultur e. Conclusion: Rapid culture substantially reduced total test time, wa s less labour-intensive and was as sensitive as standard culture for t he isolation of measles virus from clinical specimens. (C) 1997 Elsevi er Science B.V.