Volume 85, Issue 3
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



The mosquito-transmitted pathogen West Nile virus (WNV) is not yet present in the Galápagos Archipelago of Ecuador. However, concern exists for fragile endemic island fauna after population decreases in several North American bird species and pathology in certain reptiles. We examined WNV vector competency of a Galápagos strain of mosquito ( Say). Field specimens were tested for their capacity to transmit the WN02-1956 strain of WNV after incubation at 27°C or 30°C. Rates of infection, dissemination, and transmission all increased with days post-exposure to WNV, and the highest rates were observed at 28 days. Infection rates peaked at 59% and transmission rates peaked at 44% (of mosquitoes tested). Vector efficiency increased after day 14. Rates of infection but not of transmission were significantly influence by temperature. No vertical transmission was detectable. We demonstrate that Galápagos are competent WNV vectors, and therefore should be considered an animal and public health risk for the islands and controlled wherever possible.


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  1. Kramer LD, Styer LM, Ebel GD, , 2008. A global perspective on the epidemiology of West Nile virus. Annu Rev Entomol 53: 6181.[Crossref]
  2. Dupuis AP, Marra PP, Reitsma R, Jones MJ, Louie KL, Kramer LD, , 2005. Short report: serologic evidence for West Nile virus transmission in Puerto Rico and Cuba. Am J Trop Med Hyg 73: 474476.
  3. Komar N, Clark GG, , 2006. West Nile virus activity in Latin America and the Caribbean. Rev Panam Salud Publica–Pan American J Public Health 19: 112117.[Crossref]
  4. Mattar S, Edwards E, Laguado J, Gonzalez M, Alvarez J, Komar N, , 2005. West Nile Virus antibodies in Colombian horses. Emerg Infect Dis 11: 14971498.[Crossref]
  5. Morales MA, Barrandeguy M, Fabbri C, Garcia JB, Vissani A, Trono K, Gutierrez G, Pigretti S, Menchaca H, Garrido N, Taylor N, Fernandez F, Levis S, Enria D, , 2006. West Nile virus isolation from equines in Argentina, 2006. Emerg Infect Dis 12: 15591561.[Crossref]
  6. Bosch I, Herrera F, Navarro JC, Lentino M, Dupuis A, Maffei J, Jones M, Fernandez E, Perez N, Perez-Eman J, Guimaraes AE, Barrera R, Valero N, Ruiz J, Velasquez G, Martinez J, Comach G, Komar N, Spielman A, Kramer L, , 2007. West Nile virus, Venezuela. Emerg Infect Dis 13: 651653.[Crossref]
  7. Invasive Species in Galapagos Carrion V, , 2009. , Conservation and Sustainable Development. Available at: www.galapagoapark.org
  8. UNESCO: United Nations Educational Scientific and Cultural Organization, 2010. Galápagos Islands. World Heritage List. Available at: http://whc.unesco.org/en/list/1.
  9. Thiel T, Whiteman NK, Tirape A, Baquero MI, Cedeno V, Walsh T, Uzcategui GJ, Parker PG, , 2005. Characterization of canarypox-like viruses infecting endemic birds in the Galápagos Islands. J Wildl Dis 41: 342353.[Crossref]
  10. Padilla LR, Santiago-Alarcon D, Merkel J, Miller RE, Parker PG, , 2004. Survey for Haemoproteus spp., Trichomonas gallinae, Chlamydophila psittaci, and Salmonella spp. in Galápagos Islands Columbiformes. J Zoo Wildl Med 35: 6064.[Crossref]
  11. Daszak P, Cunningham AA, Hyatt AD, , 2000. Emerging infectious diseases of wildlife—threats to biodiversity and human health. Science 287: 443449.[Crossref]
  12. Wikelski M, Foufopoulos J, Vargas H, Snell H, , 2004. Galápagos birds and diseases: invasive pathogens as threats for island species. Ecology and Sociery 9: 5.[Crossref]
  13. Briese T, Bernard KA, , 2005. West Nile virus: an old virus learning new tricks? J Neurovirol 11: 469475.[Crossref]
  14. Centers for Disease Control and Prevention, 2009. Bird Species: Vertebrate Ecology. West Nile Virus Activity. Bird Species Reported to CDCs West Nile Virus Avian Mortality Database from 1999–Present. Atlanta: Division of Vector Borne Infectious Diseases, Centers for Disease Control and Prevention.
  15. LaDeau SL, Kilpatrick AM, Marra PP, , 2007. West Nile virus emergence and large-scale declines of North American bird populations. Nature 447: 710713.[Crossref]
  16. Kilpatrick AM, LaDeau SL, Marra PP, , 2007. Ecology of West Nile virus transmission and its impact on birds in the western hemisphere. Auk 124: 11211136.[Crossref]
  17. Peterson AT, Komar N, Komar O, , 2004. Priority contribution West Nile virus in the New World: potential impacts on bird species. Bird Conserv Int 14: 215232.[Crossref]
  18. Kilpatrick AM, Daszak P, Goodman SJ, Rogg H, Kramer LD, Cedeno V, Cunningham AA, , 2006. Predicting pathogen introduction: West Nile virus spread to Galápagos. Conserv Biol 20: 12241231.[Crossref]
  19. Causton C, Peck SB, Sinclair BJ, Roque-Albelo L, Hodgson CJ, Landrye B, , 2006. Alien insects: threats and implications for conservation of Galápagos Islands. Ann Entomol Soc Am 99: 121143.[Crossref]
  20. Bataille A, Cunningham AA, Cedeño V, Cruz M, Eastwood G, Fonseca DM, Causton CE, Azuero R, Loayza J, Martinez JD, Goodman SJ, , 2009. Evidence for regular ongoing introductions of mosquito disease vectors into the Galápagos Islands. Proc Biol Sci 276: 37693775.[Crossref]
  21. Centers for Disease Control and Prevention, 2007. West Nile virus activity – United States, 2006. MMWR Morb Mortal Wkly Rep 56: 556559.
  22. Bataille A, Cunningham AA, Cedeno V, Patino L, Constantinou A, Kramer LD, Goodman SJ, , 2009. Natural colonization and adaptation of a mosquito species in Galápagos and its implications for disease threats to endemic wildlife. Proc Natl Acad Sci USA 106: 1023010235.[Crossref]
  23. Whiteman NK, Goodman SJ, Sinclair BJ, Walsh T, Cunningham AA, Kramer LD, Parker PG, , 2005. Establishment of the avian disease vector Culex quinquefasciatus Say, 1823 (Diptera: Culicidae) on the Galápagos Islands, Ecuador. Ibis 147: 844847.[Crossref]
  24. Gratz NG, Steffen R, Cocksedge W, , 2000. Why aircraft disinsection? Bull World Health Organ 78: 9951004.
  25. Keyghobadi N, LaPointe D, Fleischer RC, Fonseca DM, , 2006. Fine-scale population genetic structure of a wildlife disease vector: the southern house mosquito on the island of Hawaii. Mol Ecol 15: 39193930.[Crossref]
  26. LaPointe DA, Hofmeister EK, Atkinson CT, Porter RE, Dusek RJ, , 2009. Experimental infection of Hawai`I `Amakihi (Hemignathus virens) with West Nile virus and competence of a co-occurring vector, Culex quinquefasciatus: potential impacts on endemic Hawaiian avifauna. J Wildl Dis 45: 257271.[Crossref]
  27. Reisen WK, Meyer RP, Milby MM, Presser SB, Emmons RW, Hardy JL, Reeves WC, , 1992. Ecological observations on the 1989 Outbreak of St. Louis Encephalitis virus in the southern San Joaquin Valley of California. J Med Entomol 29: 472482.[Crossref]
  28. Molaei G, Andreadis TG, Armstrong PM, Bueno R, Dennett JA, Real SV, Sargent C, Bala A, Randle Y, Guzman H, da Rosa AT, Wuithiranyagool T, Tesh RB, , 2007. Host feeding pattern of Culex quinquefasciatus (Diptera: Culicidae) and its role in transmission of West Nile virus in Harris County, Texas. Am J Trop Med Hyg 77: 7381.
  29. Tempelis DH, , 1974. Host-feeding patterns of mosquitoes, with a review of advances in analysis of blood meals by serology. J Med Entomol 11: 635653.[Crossref]
  30. Anderson SL, Richards SL, Tabachnick WJ, Smartt CT, , 2010. Effects of West Nile virus dose and extrinsic incubation temperature on temporal progression of vector competence in Culex pipiens quinquefasciatus . J Am Mosq Control Assoc 26: 103107.[Crossref]
  31. Tempelis CH, Hayes RO, Hess AD, Reeves WC, , 1970. Blood-feeding habits of 4 species of mosquito found in Hawaii. Am J Trop Med Hyg 19: 335.
  32. Vaidyanathan R, Scott TW, , 2007. Geographic variation in vector competence for West Nile virus in the Culex pipiens (Diptera: Culicidae) complex in California. Vector Borne Zoonotic Dis 7: 193198.[Crossref]
  33. Sardelis MR, Turell MJ, Dohm DJ, O'Guinn ML, , 2001. Vector competence of selected North American Culex and Coquillettidia mosquitoes for West Nile virus. Emerg Infect Dis 7: 10181022.[Crossref]
  34. Goddard LB, Roth AE, Reisen WK, Scott TW, , 2002. Vector competence of California mosquitoes for West Nile virus. Emerg Infect Dis 8: 13851391.[Crossref]
  35. Vanlandingham DL, McGee C, Klinger KA, Vessey N, Fredregillo C, Higgs S, , 2007. Short report: relative susceptibilities of south Texas mosquitoes to infection with West Nile virus. Am J Trop Med Hyg 77: 925928.
  36. Kilpatrick AM, Meola MA, Moudy RM, Kramer LD, , 2008. Temperature, viral genetics, and the transmission of West Nile virus by Culex pipiens mosquitoes. PLoS Pathog 4: e1000092, doi: 10.1371/journal.ppat.1000092.[Crossref]
  37. Jupp PG, , 1974. Laboratory Studies on Transmission of West Nile Virus by Culex (Culex) univittatus Theobald- Factors influencing transmission rate. J Med Entomol 11: 455458.[Crossref]
  38. Tabachnick WJ, , 2010. Challenges in predicting climate and environmental effects on vector-borne disease episystems in a changing world. J Exp Biol 213: 946954.[Crossref]
  39. Richards S, Mores CN, Lord CC, Tabachnick WJ, , 2007. Impact of extrinsic incubation temperature and virus exposure on vector competence of Culex pipiens quinquefasciatus Say (Diptera: Culicidae) for West Nile virus. Vector Borne Zoonotic Dis 7: 629636.[Crossref]
  40. Jansen CC, Cameron E, Northill JA, Ritchie SA, Russell RC, Van Den Hurk AF, , 2008. Vector competence of Australian mosquito species for a North American strain of West Nile virus. Vector Borne Zoonotic Dis 8: 805811.[Crossref]
  41. Kilpatrick AM, Ebel GD, Fonseca DM, Kramer LD, , 2010. Spatial and temporal variation in vector competence of Culex pipiens and Cx. restuans mosquitoes for West Nile virus. Am J Trop Med Hyg 83: 607613.[Crossref]
  42. Goddard LB, Roth AE, Reisen WK, Scott TW, , 2003. Vertical transmission of West Nile virus by three California Culex (Diptera: Culicidae) species. J Med Entomol 40: 743746.[Crossref]
  43. Komar N, Langevin S, Hinten S, Nemeth N, Edwards E, Hettler D, Davis B, Bowen R, Bunning M, , 2003. Experimental infection of North American birds with the New York 1999 strain of West Nile virus. Emerg Infect Dis 9: 311322.[Crossref]
  44. Moudy RM, Meola MA, Morin LLL, Ebel GD, Kramer LD, , 2007. A newly emergent genotype of west Nile virus is transmitted earlier and more efficiently by Culex mosquitoes. Am J Trop Med Hyg 77: 365370.
  45. Altizer S, Dobson A, Hosseini P, Hudson P, Pascual M, Rohani P, , 2006. Seasonality and the dynamics of infectious diseases. Ecol Lett 9: 467484.[Crossref]
  46. Ebel GD, Rochlin I, Longacker J, Kramer LD, , 2005. Culex restuans (Diptera: Culicidae) relative abundance and vector competence for West Nile virus. J Med Entomol 42: 838843.[Crossref]
  47. Aitken THG, , 1977. An in vitro feeding technique for artificially demonstrating virus transmission by mosquitos. Mosq News 37: 130133.
  48. Payne AF, Binduga-Gajewska I, Kauffman EB, Kramer LD, , 2006. Quantitation of flaviviruses by fluorescent focus assay. J Virol Methods 134: 183189.[Crossref]
  49. Gunay F, Alten B, Ozsoy ED, , 2010. Estimating reaction norms for predictive population parameters, age specific mortality, and mean longevity in temperature-dependent cohorts of Culex quinquefasciatus Say (Diptera: Culicidae). J Vector Ecol 35: 354362.[Crossref]
  50. Unlu I, Mackay AJ, Roy A, Yates MM, Foil LD, , 2010. Evidence of vertical transmission of West Nile virus in field-collected mosquitoes. J Vector Ecol 5: 9599.[Crossref]
  51. Fonseca DM, Smith JL, Wilkerson RC, Fleischer RC, , 2006. Pathways of expansion and multiple introductions illustrated by large genetic differentiation among worldwide populations of the southern house mosquito. Am J Trop Med Hyg 74: 284289.
  52. Kutz SJ, Hoberg EP, Polley L, Jenkins EJ, , 2005. Global warming is changing the dynamics of Arctic host-parasite systems. Proc Biol Sci 272: 25712576.[Crossref]
  53. Styer LM, Kent KA, Albright RG, Bennett CJ, Kramer LD, Bernard KA, , 2007. Mosquitoes inoculate high doses of West Nile virus as they probe and feed on live hosts. PLoS Pathog 3: 12621270.[Crossref]
  54. Nemeth N, Gould D, Bowen R, Komar N, , 2006. Natural and experimental West Nile virus infection in five raptor species. J Wildl Dis 42: 113.[Crossref]
  55. Fang Y, Reisen WK, , 2006. Previous infection with West Nile or St. Louis encephalitis viruses provides cross protection during reinfection in house finches. Am J Trop Med Hyg 75: 480485.
  56. Garcia-Rejon JE, Blitvich BJ, Farfan-Ale JA, Lorono-Pino MA, Chi Chim WA, Flores-Flores LF, Rosado-Paredes E, Baak-Baak C, Perez-Mutul J, Suarez-Solis V, Fernandez-Salas I, Beaty B, , 2010. Host-feeing preference of the mosquito, Culex quinquefasciatus, in Yucatan State, Mexico. J Insect Sci 10: 112.[Crossref]
  57. Zinser M, Ramberg F, Willot E, , 2004. Culex quinquefasciatus (Diptera: Culicidae) as a potential West Nile virus vector in Tucson, Arizona: blood meal analysis indicates feeding on both humans and birds. J Insect Sci 4: 2022.[Crossref]
  58. Hribar LJ, Stark LM, Stoner RL, Demay DJ, Nordholt AL, Hemmen MJ, Vlach JJ, Fussell EM, , 2004. Isolation of West Nile virus from mosquitoes (Diptera: Culicidae) in the Florida Keys, Monroe County, Florida. Caribb J Sci 40: 362367.
  59. Turell MJ, O'Guinn ML, Dohm DJ, Jones JW, , 2001. Vector competence of North American mosquitoes (Diptera: Culicidae) for West Nile virus. J Med Entomol 38: 130134.[Crossref]
  60. Komar N, , 2003. West Nile virus: epidemiology and ecology in North America. Adv Virus Res 61: 185234.[Crossref]

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  • Received : 31 Dec 2010
  • Accepted : 09 May 2011

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