Affiliations: *National Institute of Health, Department of Medical Sciences,
Ministry of Public Health
**CDC, Atlanta, Georgia, USA
Source: Thai Journal of Pediatrics 1999; 38(3): 190-199
Language: Thai with English abstract
Measles is the rash illness caused by measles virus. This disease is contagious infection of childhood. Measles virus is member of the paramyxoviridae family and belongs to the genus Morbillivirus. In Thailand, there has been measles immunization programme since 1984. Although the measles vaccine coverage is 80% or greater, outbreak have continued in Thailand. In the mid year of 1993-1994, the measles cases were report dramatically increasing. Thus, National Institute of Health, Department of Medical Sciences collected the whole blood from measles patients during rash and isolated virus in the B95a cell line. The isolated viruses were characterized by nucleotide sequence and compared to that of vaccine strain(Schwarz strain), The result showed that hemagglutinin gene (H-gene) sequences of five isolates were 3% different from Schwarz strain. Two of these five isolates were selected to study the antigenic variation by microneutralization test, It was found that serum specimens from fourteen vaccines neutralized the viruses but showed variation in antibody titers. This study indicated that genetic and antigenic variation existed among measles isolated during 1993-1994 but these variation did not affect the efficacy of vaccine presently used in EPI in Thailand.