GENETIC-ANALYSIS OF MEASLES VIRUSES ISOLATED IN THE UNITED-STATES, 1995-1996

Genetic analysis was conducted on 28 wild type measles viruses isolate d from outbreaks or cases in the United States during 1995-1996. These viruses were members of at least 6 distinct genetic groups, However, none of these viruses was related to the group 2 viruses that were ass ociated with the resurgence of measles in the United States between 19 89 and 1992 except for a single importation from the Philippines, The sequence data support and extend previous findings showing that transm ission of group 2 viruses within the United States was interrupted aft er 1993, The data also suggest that all measles cases that occurred in the United States in 1995-1996 were the result of importation of viru s, even in instances when the source was unknown, Molecular epidemiolo gic studies can provide a means to measure the success of measles cont rol programs by helping to identify the transmission pathways of the v irus.