Genetic divergence and dispersal of Yellow Fever Virus, Brazil

CNPq (Brazilian Agency for Scientific and Technologic Development, process 302770/02-0) and the National Institutes of Health (grant AI 50175)Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. World Health Organization Collaborating Center for Arbovirus Reference and Research. Belém, PA, Brasil.University of Texas Medical Branch. Galveston, TX, USA.University of Texas Medical Branch. Galveston, TX, USA.University of Texas Medical Branch. Galveston, TX, USA.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. World Health Organization Collaborating Center for Arbovirus Reference and Research. Belém, PA, Brasil.University of Texas Medical Branch. Galveston, TX, USA.An analysis of 79 yellow fever virus(YFV) isolates collected from 1935 to 2001 in Brazil showed a single genotype (South America) circulating in the country, with the exception of a single strain from Rôndonia, wich represented South America genotype II. Brazilian YFV strains have diverged into two clades; an older clade appears to have become extinct and another has become the dominant lineage in recent years. Pairwise nucleotide diversity between strains ranged from 0 per cent to 7.4 per cent, while amino acid divergence ranged from 0 per cent to 4.6 per cent. Phylogenetic analysis indicated traffic of virus variants through large geographic areas and suggested that migration of infected people may be an important mechanism of virus dispersal. Isolation of vaccine virus from a patient with a fatal case suggests that vaccine-related illness may have been misdiagnosed in the past