Volume 77, Issue 2
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645


Studies examining the evolution of West Nile virus since its introduction into North America have identified the emergence of a new dominant genotype (WN02) that has displaced the introduced genotype (NY99). The mechanistic basis for this displacement, however, remains obscure. Although we found no detectable difference between the genotypes in either replication or fitness, there were significant differences in mosquitoes. After peroral infection, the extrinsic incubation period (EIP) of the WN02 genotype was up to 4 days shorter than the EIP of the NY99 genotype; however, after intrathoracic inoculation, there was no difference in EIP between the genotypes, suggesting that differences in genotype interaction with the mosquito midgut are likely to play a role in this phenotype. These results suggest a model for the displacement of the NY99 genotype, where earlier transmission of WN02 viruses leads to higher WN02 infection rates in avian reservoir hosts.


Article metrics loading...

The graphs shown below represent data from March 2017
Loading full text...

Full text loading...



  1. Burke DS, Monath TP, 2001. Flaviviruses. Knipe DM, Howley PM, eds. Fields Virology. 4th ed. Philadelphia: Lippincott William & Wilkins, 1043–1126.
  2. Lindenbach BD, Rice CM, 2001. Flaviviridae: The Virus and Their Replication. Fields Virology. 4th ed. Philadelphia: Lippincott William & Wilkins.
  3. Weaver SC, Barrett ADT, 2004. Transmission cycles, host range, evolution and emergence of arboviral disease. Nat Rev Microbiol 2 : 789–801. [Google Scholar]
  4. Campbell GL, Marfin AA, Lanciotti RS, Gubler DJ, 2002. West Nile virus. Lancet Infect Dis 2 : 519–529. [Google Scholar]
  5. Blitvich BJ, Fernandez-Salas I, Contreras-Cordero JF, Marlenee NL, Gonzalez-Rojas JI, Komar N, Gubler DJ, Calisher CH, Beaty BJ, 2003. Serologic evidence of West Nile virus infection in horses, Coahuila State, Mexico. Emerg Infect Dis 9 : 853–856. [Google Scholar]
  6. Cruz L, Cardenas VM, Abarca M, Rodriguez T, Reyna RF, Serpas MV, Fontaine RE, Beasley DW, da Rosa AP, Weaver SC, Tesh RB, Powers AM, Suarez-Rangel G, 2005. Serological evidence of West Nile virus activity in El Salvador. Am J Trop Med Hyg 72 : 612–615. [Google Scholar]
  7. Davis CT, Ebel GD, Lanciotti RS, Brault AC, Guzman H, Siirin M, Lambert A, Parsons RE, Beasley DW, Novak RJ, Elizondo-Quiroga D, Green EN, Young DS, Stark LM, Drebot MA, Artsob H, Tesh RB, Kramer LD, Barrett AD, 2005. Phylogenetic analysis of North American West Nile virus isolates, 2001–2004: evidence for the emergence of a dominant genotype. Virology 342 : 252–265. [Google Scholar]
  8. Dupuis AP, Marra PP, Kramer LD, 2003. Serologic evidence of West Nile virus transmission, Jamaica, West Indies. Emerg Infect Dis 9 : 860–863. [Google Scholar]
  9. Dupuis AP, Marra PP, Reitsma R, Jones MJ, Louie KL, Kramer LD, 2005. Serologic evidence for West Nile virus transmission in Puerto Rico and Cuba. Am J Trop Med Hyg 73 : 474–476. [Google Scholar]
  10. Lanciotti RS, Roehrig JT, Deubel V, Smith J, Parker M, Steele K, Crise B, Volpe KE, Crabtree MB, Scherret JH, Hall RA, MacKenzie JS, Cropp CB, Panigrahy B, Ostlund E, Schmitt B, Malkinson M, Banet C, Weissman J, Komar N, Savage HM, Stone W, McNamara T, Gubler DJ, 1999. Origin of the West Nile virus responsible for an outbreak of encephalitis in the northeastern United States. Science 286 : 2333–2337. [Google Scholar]
  11. Lorono-Pino MA, Blitvich BJ, Farfan-Ale JA, Puerto FI, Blanco JM, Marlenee NL, Rosado-Paredes EP, Garcia-Rejon J, Gubler DJ, Calisher CH, Beaty BJ, 2003. Serologic evidence of West Nile virus infection in horses, Yucatan State, Mexico. Emerg Infect Dis 9 : 857–859. [Google Scholar]
  12. Mattar S, Edwards E, Laguado J, Gonzalez M, Alvarez J, Komar N, 2005. West Nile virus antibodies in Columbian horses. Emerg Infect Dis 11 : 1497–1498. [Google Scholar]
  13. Ebel GD, Carricaburu J, Young D, Bernard KA, Kramer LD, 2004. Genetic and phenotypic variation of West Nile virus in New York, 2000–2003. Am J Trop Med Hyg 71 : 493–500. [Google Scholar]
  14. Snappin KW, Holmes EC, Young DS, Bernard KA, Kramer LD, Ebel GD, 2007. Declining growth rate of West Nile virus in North America. J Virol 81 : 2531–2534. [Google Scholar]
  15. Ciota AT, Lovelace AO, Ngo KA, Le AN, Maffei JG, Franke MA, Payne AF, Jones SA, Kauffman EB, Kramer LD, 2007. Cell-specific adaptation of two flaviviruses following serial passage in mosquito cell culture. Virology 357 : 165–174. [Google Scholar]
  16. Holland JJ, De La Torre JC, Clarke DK, Duarte E, 1991. Quantitation of relative fitness and great adaptability of clonal populations of RNA viruses. J Virol 65 : 2960–2967. [Google Scholar]
  17. Aitken THG, 1977. An in vitro feeding technique for artificially demonstrating virus transmission by mosquitoes. Mosq News 37 : 130–133. [Google Scholar]
  18. Novella IS, Ball LA, Wertz GW, 2004. Fitness analyses of vesicular stomatitis strains with rearranged genomes reveal replicative disadvantages. J Virol 78 : 9837–9841. [Google Scholar]
  19. Kramer LD, Ebel GD, 2003. Dynamics of flavivirus infection in mosquitoes. Adv Virus Res 60 : 187–232. [Google Scholar]
  20. Macdonald G, 1961. Epidemiologic models in studies of vector-borne diseases. Public Health Rep 76 : 753–764. [Google Scholar]
  21. Anderson JR, Rico-Hesse R, 2006. Aedes aegypti vectorial capacity is determined by the infecting genotype of dengue virus. Am J Trop Med Hyg 75 : 886–892. [Google Scholar]
  22. Rico-Hesse R, Harrison LM, Salas RA, Tovar D, Nisalak A, Ramos C, Boshell J, de Mesa MT, Nogueira RM, da Rosa AT, 1997. Origins of dengue type 2 viruses associated with increased pathogenicity in the Americas. Virology 230 : 244–251. [Google Scholar]
  23. Thu HM, Lowry K, Myint TT, Shwe TN, Han AM, Khin KK, Thant KZ, Thein S, Aaskov J, 2004. Myanmar dengue outbreak associated with displacement of serotypes 2, 3, and 4 by dengue 1. Emerg Infect Dis 10 : 593–597. [Google Scholar]
  24. Wittke V, Robb TE, Thu HM, Nisalak A, Nimmannitya S, Kalayanrooj S, Vaughn DW, Endy TP, Holmes EC, Aaskov JG, 2002. Extinction and rapid emergence of strains of dengue 3 virus during an interepidemic period. Virology 301 : 148–156. [Google Scholar]
  25. Armstrong PM, Rico-Hesse R, 2001. Differential susceptibility of Aedes aegypti to infection by the American and Southeast Asian genotypes of dengue type 2 virus. Vector Borne Zoonotic Dis 1 : 159–168. [Google Scholar]
  26. Armstrong PM, Rico-Hesse R, 2003. Efficiency of dengue serotype 2 virus strains to infect and disseminate in Aedes aegypti. Am J Trop Med Hyg 68 : 539–544. [Google Scholar]
  27. Cologna R, Armstrong PM, Rico-Hesse R, 2005. Selection for virulent dengue viruses occurs in humans and mosquitoes. J Virol 79 : 853–859. [Google Scholar]

Data & Media loading...


  • Received : 27 Feb 2007
  • Accepted : 27 Apr 2007

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error