GENETIC RELATEDNESS OF SINDBIS VIRUS-STRAINS FROM EUROPE, MIDDLE-EAST, AND AFRICA

The relatedness of 40 strains of Sindbis virus (SIN) from Europe, the Middle East, and Africa was investigated by limited sequencing within the gene encoding the E2 glycoprotein corresponding to amino acid resi dues 117 to 229 and encompassing one of the major neutralization epito pes. Phylogenetic analyses using distance matrix and parsimonious meth ods identified two major genetic clusters of western SIN strains, alth ough the variability was less than that of the corresponding region fo r Venezuelan equine encephalomyelitis virus with a maximum divergence of 12.4% versus 28.5%, respectively. One cluster comprising 19 strains included the HR derivate of the Egypt SIN prototype, AR339, and strai ns from Israel, Saudi-Arabia, Italy, Slovak Republic, Azerbaijan, as w ell as three Swedish strains. Another cluster of 17 strains included t he Ockelbo virus (OCK) prototype, Edsbyn 5/82, and the majority of SIN strains from northern Europe including strains from Sweden, Norway, a nd Karelia, as well as two strains from South Africa. A third cluster, supported by the Neighbor Joining method, was made up of four strains from South Africa, Uganda, and Cameroon. Residue 212, either Set or T hr, previously appointed important for the differences in neutralizati on assays between SIN and Edsbyn 5/82, respectively, correlated with t he two major genetic clusters, but was a Thr for two of the three Swed ish strains in the SIN prototype cluster, and a Ser in one Swedish and one Karelian strain in the OCK cluster, The finding of strains simila r to prototype SIN in Middle Sweden and of strains in South Africa rel ating to the northern cluster of SIN strains supports the notion of th e dispersal of SIN by migrating birds as previously suggested for New World alphaviruses. (C) 1996 academic Press, Inc.