Saint Louis encephalitis virus (SLEV), a member of the genus (family ), is an encephalitogenic arbovirus broadly distributed in the Americas. Phylogenetic analysis based on the full-length E gene sequences obtained for 30 Brazilian SLEV strains was performed using different methods including Bayesian and relaxed molecular clock approaches. A new genetic lineage was suggested, hereafter named genotype VIII, which co-circulates with the previously described genotype V in the Brazilian Amazon region. Genotypes II and III were restricted to São Paulo state (South-east Atlantic rainforest ecosystem). The analysis also suggested the emergence of an SLEV common ancestor between 1875 and 1973 (mean of 107 years ago), giving rise to two major genetic groups: genotype II, more prevalent in the North America, and a second group comprising the other genotypes (I and III–VIII), broadly dispersed throughout the Americas, suggesting that SLEV initially emerged in South America and spread to North America. In conclusion, the current study demonstrates the high genetic variability of SLEV and its geographical dispersion in Brazil and other New World countries.


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  1. Auguste, A. J., Pybus, O. G. & Carrington, C. V. F.(2009). Evolution and dispersal of St. Louis encephalitis virus in the Americas. Infect Genet Evol 9, 709–715.[CrossRef] [Google Scholar]
  2. Baillie, G. J., Kolokotronis, S.-O., Waltari, E., Maffei, J. G., Kramer, L. D. & Perkins, S. L.(2008). Phylogenetic and evolutionary analyses of St. Louis encephalitis virus genomes. Mol Phylogenet Evol 47, 717–728.[CrossRef] [Google Scholar]
  3. Bryant, J. E., Holmes, E. C. & Barrett, A. D. T.(2007). Out of Africa: a molecular perspective on the introduction of yellow fever virus into the Americas. PLoS Pathog 3, e75.[CrossRef] [Google Scholar]
  4. Calisher, C. H. & Gould, E. A.(2003). Taxonomy of the virus family Flaviviridae. In Advances in Virus Research, vol. 59, pp. 1–19. Edited by Maramorosch, K., Murphy, F. A. & Shatkin, A. J.. San Diego, CA. : Elsevier. [Google Scholar]
  5. Dégallier, N., Travassos da Rosa, A. P. A., Silva, J. M. C., Rodrigues, S. G., Vasconcelos, P. F. C. & Travassos da Rosa, J. F. S.(1992). As aves como hospedeiras de arbovírus na Amazônia brasileira. Boletim Museu Paraense Emílio Goeldi 8, 69–111. [Google Scholar]
  6. Diaz, L. A., Re, V., Almirón, W. R., Farias, A., Vázquez, A. & Sanchez-Seco, M. P.(2006). Genotype III Saint Louis encephalitis virus outbreak, Argentina. Emerg Infect Dis 12, 1752–1754.[CrossRef] [Google Scholar]
  7. Drummond, A. J., Pybus, O., Rambaut, A., Forsberg, R. & Rodrigo, A.(2003). Measurably evolving populations. Trends Ecol Evol 18, 481–488.[CrossRef] [Google Scholar]
  8. Drummond, A. J., Ho, S. Y. W., Phillips, M. J. & Rambaut, A.(2006). Relaxed phylogenetics and dating with confidence. PLoS Biol 4, e88.[CrossRef] [Google Scholar]
  9. Felsenstein, J.(1985). Confidence limits on phylogenies: an approach using the bootstrap. Evolution 39, 783–791.[CrossRef] [Google Scholar]
  10. Hervé, J. P., Dégallier, N., Travassos da Rosa, A. P. A., Pinheiro, F. P. & Sá Filho, G. C.(1986).Aspectos ecológicos das arboviroses. Instituto Evandro Chagas: 50 anos de Contribuição às Ciências Biológicas e à Medicina Tropical, vol. 1, pp. 409–437. Belém, Brasil. : Fundação SESP. [Google Scholar]
  11. Huelsenbeck, J. P., Ronquist, F., Nielsen, R. & Bollback, J. P.(2001). MrBAYES: Bayesian inference of phylogeny and its impact on evolutionary biology. Science 14, 2310–2314. [Google Scholar]
  12. Kramer, L. D. & Chandler, L. J.(2001). Phylogenetic analysis of the envelope gene of St. Louis encephalitis virus. Arch Virol 146, 2341–2355.[CrossRef] [Google Scholar]
  13. Kramer, L. D., Presser, S. B., Hardy, J. L. & Jackson, A. O.(1997). Genotypic and phenotypic variation of selected Saint Louis encephalitis viral strains isolated in California. Am J Trop Med Hyg 57, 222–229. [Google Scholar]
  14. Kumar, S., Tamura, K. & Nei, M.(2008).Molecular Evolutionary Genetic Analysis. Version 4.0. Philadelphia: The Pennsylvania State University.
  15. May, F. J., Li, L., Zhang, S., Guzman, H., Beasley, D. W., Tesh, R. B., Higgs, S., Raj, P., Bueno, R., Jr & other authors(2008). Genetic variation of St. Louis encephalitis virus. J Gen Virol 89, 1901–1910.[CrossRef] [Google Scholar]
  16. Medeiros, D. B., Nunes, M. R., Vasconcelos, P. F., Chang, G. J. & Kuno, G.(2007). Complete genome characterization of Rocio virus (Flavivirus: Flaviviridae), a Brazilian flavivirus isolated from a fatal case of encephalitis during an epidemic in São Paulo state. J Gen Virol 88, 2237–2246.[CrossRef] [Google Scholar]
  17. Mondini, A., Bronzoni, R., Cardeal, I., Santos, T., Lázaro, E., Nunes, S., Silva, G., Madrid, M., Rahal, P. & Figueiredo, L.(2007a). Simultaneous infection by DENV-3 and SLEV in Brazil. J Clin Virol 40, 84–86.[CrossRef] [Google Scholar]
  18. Mondini, A., Cardeal, I. L., Lázaro, E., Nunes, S. H., Moreira, C. C., Rahal, P., Maia, I. L., Franco, C., Góngora, D. V. & other authors(2007b). Saint Louis encephalitis virus, Brazil. Emerg Infect Dis 13, 176–178.[CrossRef] [Google Scholar]
  19. Ottendorfer, C. L., Ambrose, J. H., White, G. S., Unnasch, T. R. & Stark, L. M.(2009). Isolation of genotype V St. Louis encephalitis virus in Florida. Emerg Infect Dis 15, 604–606.[CrossRef] [Google Scholar]
  20. Pinheiro, F. P., LeDuc, J. W., Travassos da Rosa, A. P. A. & Leite, O. F.(1981). Isolation from St. Louis encephalitis virus from a patient in Belém, Brazil. Am J Trop Med Hyg 30, 145–148. [Google Scholar]
  21. Posada, D. & Crandall, K. A.(1998). Modeltest: testing the model of DNA substitution. Bioinformatics 14, 817–818.[CrossRef] [Google Scholar]
  22. Reisen, W. K.(2003). Epidemiology of St. Louis encephalitis virus. In Advances in Virus Research, vol. 61, pp. 139–183. Edited by Maramorosch, K., Murphy, F. A. & Shatkin, A. J.. San Diego. : Elsevier. [Google Scholar]
  23. Rocco, I. M., Santos, C. L. S., Bisordi, I., Petrella, S. M. C. N., Pereira, L. E., Souza, R. P., Coinbra, L. M., Bessa, T. A. F., Oshiro, F. M. & other authors(2005). St. Louis encephalitis: first virus isolation from a human in São Paulo State, Brazil. Rev Inst Med Trop Sao Paulo 47, 281–285.[CrossRef] [Google Scholar]
  24. Rodrigues, S. G., Oliva, O. P., Araújo, F. A. A., Martins, L. C., Chiang, J. O., Henriques, D. F., Silva, E. V. P., Rodrigues, D. S. G., Prazeres, A. S. C. & other authors(2009). Epidemiology of Saint Louis encephalitis virus in the Brazilian Amazon region and in the State of Mato Grosso do Sul, Brazil: elevated prevalence of antibodies in horses. Rev Panam Salud Publica 1, 81–86. [Google Scholar]
  25. Saitou, N. & Nei, M.(1987). The neighbor-joining method: a new method for reconstruction phylogenetic trees. Mol Biol Evol 4, 406–425. [Google Scholar]
  26. Sanger, F., Nicklen, S. & Coulson, A. R.(1977). DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A 74, 5463–5467.[CrossRef] [Google Scholar]
  27. Santos, C. L. S., Sallum, M. A. M., Franco, H. M., Oshiro, F. M. & Rocco, I. M.(2006). Genetic characterization of St. Louis encephalitis virus isolated from human in São Paulo, Brazil. Mem Inst Oswaldo Cruz 101, 57–63.[CrossRef] [Google Scholar]
  28. Spense, L. P.(1980). St. Louis encephalitis in tropical America. In St. Louis Encephalitis, pp. 451–471. Edited by Monath, T. P.. Washington, DC. : American Public Health Association. [Google Scholar]
  29. Swofford, D. L.(1999).paup: Phylogenetic analysis using parsimony (and other methods), version 4. Sunderland, Mass: Sinauer Associates.
  30. Travassos da Rosa, A. P. A., Vasconcelos, P. F. C., Travassos da Rosa, J. F. S., Dégallier, N., Sá Filho, G. C. & Hervé, J. P.(1985).Encefalites na Amazônia Brasileira. 1 Seminário Nacional de Zoonoses, 19–22 November 1985, p. 15. Belo Horizonte: Minas Gerais.
  31. Travassos da Rosa, A. P. A., Travassos da Rosa, J. F. S., Pinheiro, F. P. & Vasconcelos, P. F. C.(1997). Arboviroses. In Doenças Infecciosas e Parasitárias. Enfoque Amazônico, pp. 208–225. Edited by Leão, R. N. Q.. Belém, Brazil. : CEJUP. [Google Scholar]
  32. Tsai, T. F. & Mitchell, C. J.(1988). St. Louis encephalitis. In The Arboviruses: Epidemiology and Ecology, pp. 431–458. Edited by Monath, T. P.. Boca Raton, FL. : CRC Press. [Google Scholar]
  33. Twiddy, S. S. & Holmes, E. C.(2003). The extent of homologous recombination in members of the genus Flavivirus. J Gen Virol 84, 429–440.[CrossRef] [Google Scholar]
  34. Vasconcelos, P. F. C., Travassos da Rosa, J. F. S., Travassos da Rosa, A. P. A., Dégallier, N., Pinheiro, F. P. & Sá Filho, G. C.(1991). Epidemiologia das encefalites por Arbovírus na Amazônia Brasileira. Rev Inst Med Trop Sao Paulo 33, 465–476 (in Portuguese ).[CrossRef] [Google Scholar]
  35. Vasconcelos, P. F. C., Travassos da Rosa, A. P. A., Pinheiro, F. P., Shope, R. E., Travassos da Rosa, J. F. S., Rodrigues, S. G., Dégallier, N. & Travassos da Rosa, E. S.(1998). Arboviruses pathogenic for man in Brazil. In An Overview of Arbovirology in Brazil and Neighbouring Countries, pp. 72–99. Edited by Travassos da Rosa, A. P. A., Vasconcelos, P. F. C. & Travassos da Rosa, J. F. S.. Belém, Brazil. : Instituto Evandro Chagas. [Google Scholar]
  36. Zanotto, P. M. A., Gao, G. F., Venugopal, K., Gritsun, T. S., Marin, S., Jiang, W. R., Reid, H. W. & Gould, E. A.(1995). An RNA virus cline across the Northern Hemisphere. Virology 210, 152–159.[CrossRef] [Google Scholar]
  37. Zanotto, P. M. A., Gould, E. A., Gao, G. F., Harvey, P. H. & Holmes, E. C.(1996). Population dynamics of flaviviruses revealed by molecular phylogenies. Proc Natl Acad Sci U S A 93, 548–553.[CrossRef] [Google Scholar]

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vol. , part 10, pp. 2420 - 2427

SLEV strains included in the phylogenetic analysis of the E gene using Bayesian and relaxed molecular clock methods [PDF](28 KB)

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