FREE SHIPPING over $40
OVER 10000 FIVE-STAR REVIEWS
5% OFF ALL SUBSCRIPTIONS
100% HAPPINESS GUARANTEE
Analyze Diet
0
PLoS neglected tropical diseases2020; 14(11); e0008841; doi: 10.1371/journal.pntd.0008841

West Nile virus in California, 2003-2018: A persistent threat.

Abstract: The California Arbovirus Surveillance Program was initiated over 50 years ago to track endemic encephalitides and was enhanced in 2000 to include West Nile virus (WNV) infections in humans, mosquitoes, sentinel chickens, dead birds and horses. This comprehensive statewide program is a function of strong partnerships among the California Department of Public Health (CDPH), the University of California, and local vector control and public health agencies. This manuscript summarizes WNV surveillance data in California since WNV was first detected in 2003 in southern California. From 2003 through 2018, 6,909 human cases of WNV disease, inclusive of 326 deaths, were reported to CDPH, as well as 730 asymptomatic WNV infections identified during screening of blood and organ donors. Of these, 4,073 (59.0%) were reported as West Nile neuroinvasive disease. California's WNV disease burden comprised 15% of all cases that were reported to the U.S. Centers for Disease Control and Prevention during this time, more than any other state. Additionally, 1,299 equine WNV cases were identified, along with detections of WNV in 23,322 dead birds, 31,695 mosquito pools, and 7,340 sentinel chickens. Annual enzootic detection of WNV typically preceded detection in humans and prompted enhanced intervention to reduce the risk of WNV transmission. Peak WNV activity occurred from July through October in the Central Valley and southern California. Less than five percent of WNV activity occurred in other regions of the state or outside of this time. WNV continues to be a major threat to public and wild avian health in California, particularly in southern California and the Central Valley during summer and early fall months. Local and state public health partners must continue statewide human and mosquito surveillance and facilitate effective mosquito control and bite prevention measures.
Get Full Text
Publication Date: 2020-11-18 PubMed ID: 33206634PubMed Central: PMC7710070DOI: 10.1371/journal.pntd.0008841Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
LinkedInCopy
  • Journal Article
  • Research Support
  • N.I.H.
  • Extramural
  • Research Support
  • U.S. Gov't
  • Non-P.H.S.
  • Research Support
  • U.S. Gov't
  • P.H.S.

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article documents the ongoing threat of West Nile virus (WNV) in California, based on data collected between 2003 and 2018 from the California Arbovirus Surveillance Program. The study reveals the persisting presence of WNV, evidenced by numerous human cases, infected animals, and positive mosquito pools.

Overview of the Research

  • The study was conducted as part of the longstanding California Arbovirus Surveillance Program. This program surveils infectious mosquito-borne diseases including West Nile virus (WNV).
  • In partnership with the California Department of Public Health (CDPH), University of California, and other public health agencies, the study gathered and analyzed data from 2003 to 2018.
  • The aim of the research was to understand and document the presence and impact of WNV in California.

Findings from the Research

  • During the observed period, there were 6,909 reported human cases of WNV, which resulted in 326 deaths.
  • Out of the reported cases, 59.0% (4,073 cases) were identified as West Nile neuroinvasive disease, a more severe and invasive form of the illness.
  • Surprisingly, California’s WNV burden made up 15% of all cases that were reported to the U.S. Centers for Disease Control and Prevention (CDC) during the same period, a higher percentage than any other state.
  • The study also uncovered a significant number of infections in animals and birds, with over 1,299 equine WNV cases, 23,322 affected dead birds, and 7,340 sentinel chickens testing positive for WNV.
  • The monitoring of mosquito pools also revealed substantial infection levels with 31,695 mosquito pools tested positive for the virus.

Implications of the Research

  • One of the patterns observed in the study data is that the highest WNV activity generally occurred from July to October in the Central Valley and southern California, with less than five percent occurring in other regions or outside this time frame.
  • This suggests that WNV poses the most significant threat during the summer and early fall months in southern California and the Central Valley.
  • In conclusion, the presence of WNV is a persistent issue for public health and wildlife avian health in California.
  • In response to the findings, the authors suggest that local and state public health partners must continue their surveillance efforts and implement effective mosquito control and bite prevention measures.

Cite This Article

APA
Snyder RE, Feiszli T, Foss L, Messenger S, Fang Y, Barker CM, Reisen WK, Vugia DJ, Padgett KA, Kramer VL. (2020). West Nile virus in California, 2003-2018: A persistent threat. PLoS Negl Trop Dis, 14(11), e0008841. https://doi.org/10.1371/journal.pntd.0008841

Publication

PLoS neglected tropical diseases
ISSN: 1935-2735
NlmUniqueID: 101291488
Country: United States
Language: English
Volume: 14
Issue: 11
Pages: e0008841

Researcher Affiliations

Snyder, Robert E
  • California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America.
Feiszli, Tina
  • California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America.
Foss, Leslie
  • California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America.
Messenger, Sharon
  • California Department of Public Health, Division of Communicable Disease Control, Richmond, California, United States of America.
Fang, Ying
  • Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America.
Barker, Christopher M
  • Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America.
Reisen, William K
  • Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America.
Vugia, Duc J
  • California Department of Public Health, Division of Communicable Disease Control, Richmond, California, United States of America.
Padgett, Kerry A
  • California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America.
Kramer, Vicki L
  • California Department of Public Health, Vector-Borne Disease Section, Richmond and Sacramento, California, United States of America.

MeSH Terms

  • Animals
  • Base Sequence
  • Birds / virology
  • California / epidemiology
  • Chickens / virology
  • Culex / virology
  • Epidemiological Monitoring
  • Horses / virology
  • Humans
  • Mosquito Vectors / classification
  • Mosquito Vectors / virology
  • RNA, Viral / genetics
  • Seasons
  • Sequence Analysis, RNA
  • West Nile Fever / epidemiology
  • West Nile Fever / veterinary
  • West Nile virus / genetics
  • West Nile virus / isolation & purification

Grant Funding

  • R01 AI055607 / NIAID NIH HHS
  • U01CK000516 / ACL HHS
  • U50 CK000410 / NCEZID CDC HHS
  • U01 CK000516 / NCEZID CDC HHS
  • U01 EH000418 / NCEH CDC HHS

Conflict of Interest Statement

The authors have declared that no competing interests exist.

References

This article includes 94 references
  1. Reisen W, Lothrop H, Chiles R, Madon M, Cossen C, Woods L. West Nile virus in California. Emerg Infect Dis 2004;10(8):1369–78.
    doi: 10.3201/eid1008.040077pmc: PMC3320391pubmed: 15496236google scholar: lookup
  2. Jia XY, Briese T, Jordan I, Rambaut A, Chi HC, Mackenzie JS. Genetic analysis of West Nile New York 1999 encephalitis virus. Lancet 1999;354(9194):1971–2.
    doi: 10.1016/s0140-6736(99)05384-2pubmed: 10622305google scholar: lookup
  3. Centers for Disease Control and Prevention. Outbreak of West Nile-like viral encephalitis—New York, 1999. MMWR 1999;48(38):845–9.
    pubmed: 10563521
  4. U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. West Nile Virus in the United States: Guidelines for Surveillance, Prevention, and Control. 4th ed. Fort Collins, Colorado; 2013.
  5. United States Department of Agriculture, Animal and Plant Health Inspection Service. Equine West Nile Virus Case Reporting and Surveillance Information, 2018. .
  6. Komar N, Langevin S, Hinten S, Nemeth N, Edwards E, Hettler D. Experimental infection of North American birds with the New York 1999 strain of West Nile virus. Emerg Infect Dis 2003;9(3):311–22.
    doi: 10.3201/eid0903.020628pmc: PMC2958552pubmed: 12643825google scholar: lookup
  7. Centers for Disease Control and Prevention. West Nile virus disease cases and deaths reported to CDC by year and clinical presentation, 1999–2019. .
  8. Petersen LR. Epidemiology of West Nile Virus in the United States: Implications for Arbovirology and Public Health. J Med Entomol 2019;56(6):1456–62.
    doi: 10.1093/jme/tjz085pubmed: 31549728google scholar: lookup
  9. Longshore WA Jr.. Introduction. Am J Hyg 1960;71:363–7.
    doi: 10.1093/oxfordjournals.aje.a120119pubmed: 14418180google scholar: lookup
  10. Longshore WA Jr., Stevens IM, Hollister AC Jr., Gittelsohn A, Lennette EH. Epidemiologic observations on acute infectious encephalitis in California, with special reference to the 1952 outbreak. Am J Hyg 1956;63(1):69–86.
    doi: 10.1093/oxfordjournals.aje.a119793pubmed: 13282889google scholar: lookup
  11. Howitt BF. Human Equine Encephalomyelitis and St. Louis Encephalitis in California, 1939–1941. Am J Public Health Nations Health 1942;32(5):503–15.
    doi: 10.2105/ajph.32.5.503pmc: PMC1526920pubmed: 18015614google scholar: lookup
  12. Reeves WC, Hammon WM, Longshore WA Jr., Mc CH, Geib AF. Epidemiology of the arthropod-borne viral encephalitides in Kern County, California, 1943–1952. Publ Public Health Univ Calif 1962;4:1–257.
    pubmed: 14491029
  13. Reeves WC, Milby MM, Reisen WK. Development of a statewise arbovirus surveillance program and models of vector populations and virus transmission. Sacramento, California: California Mosquito and Vector Control Association, Inc.; 1990. p. 431–59.
  14. California Department of Public Health Vector-Borne Disease Sectin. California Mosquito-Borne Virus Surveillance & Response Plan. Sacramento, CA: California Department of Public Health; 2017.
  15. Lanciotti RS, Roehrig JT, Deubel V, Smith J, Parker M, Steele K. Origin of the West Nile virus responsible for an outbreak of encephalitis in the northeastern United States. Science 1999;286(5448):2333–7.
    doi: 10.1126/science.286.5448.2333pubmed: 10600742google scholar: lookup
  16. Bin H, Grossman Z, Pokamunski S, Malkinson M, Weiss L, Duvdevani P. West Nile fever in Israel 1999–2000: from geese to humans. Ann N Y Acad Sci 2001;951:127–42.
    doi: 10.1111/j.1749-6632.2001.tb02691.xpubmed: 11797770google scholar: lookup
  17. Mann BR, McMullen AR, Swetnam DM, Barrett AD. Molecular epidemiology and evolution of West Nile virus in North America. Int J Environ Res Public Health 2013;10(10):5111–29.
    doi: 10.3390/ijerph10105111pmc: PMC3823310pubmed: 24135819google scholar: lookup
  18. Brault AC, Huang CY, Langevin SA, Kinney RM, Bowen RA, Ramey WN. A single positively selected West Nile viral mutation confers increased virogenesis in American crows. Nat Genet 2007;39(9):1162–6.
    doi: 10.1038/ng2097pmc: PMC2291521pubmed: 17694056google scholar: lookup
  19. Davis CT, Ebel GD, Lanciotti RS, Brault AC, Guzman H, Siirin M. Phylogenetic analysis of North American West Nile virus isolates, 2001–2004: evidence for the emergence of a dominant genotype. Virology 2005;342(2):252–65.
    doi: 10.1016/j.virol.2005.07.022pubmed: 16137736google scholar: lookup
  20. Moudy RM, Meola MA, Morin LL, Ebel GD, Kramer LD. A newly emergent genotype of West Nile virus is transmitted earlier and more efficiently by Culex mosquitoes. Am J Trop Med Hyg 2007;77(2):365–70.
    pubmed: 17690414
  21. McMullen AR, May FJ, Li L, Guzman H, Bueno R Jr., Dennett JA. Evolution of new genotype of West Nile virus in North America. Emerg Infect Dis 2011;17(5):785–93.
    doi: 10.3201/eid1705.101707pmc: PMC3321787pubmed: 21529385google scholar: lookup
  22. Duggal NK, Reisen WK, Fang Y, Newman RM, Yang X, Ebel GD. Genotype-specific variation in West Nile virus dispersal in California. Virology 2015;485:79–85.
    doi: 10.1016/j.virol.2015.07.004pmc: PMC4619151pubmed: 26210076google scholar: lookup
  23. Nielsen CF, Armijos MV, Wheeler S, Carpenter TE, Boyce WM, Kelley K. Risk factors associated with human infection during the 2006 West Nile virus outbreak in Davis, a residential community in northern California. Am J Trop Med Hyg 2008;78(1):53–62.
    pmc: PMC2215055pubmed: 18187785
  24. Carney RM, Husted S, Jean C, Glaser C, Kramer V. Efficacy of aerial spraying of mosquito adulticide in reducing incidence of West Nile Virus, California, 2005. Emerg Infect Dis 2008;14(5):747–54.
    doi: 10.3201/eid1405.071347pmc: PMC2600250pubmed: 18439356google scholar: lookup
  25. Jean CM, Honarmand S, Louie JK, Glaser CA. Risk factors for West Nile virus neuroinvasive disease, California, 2005. Emerg Infect Dis 2007;13(12):1918–20.
    doi: 10.3201/eid1312.061265pmc: PMC2876738pubmed: 18258047google scholar: lookup
  26. Francisco AM, Glaser C, Frykman E, Cole B, Cheung M, Meyers H. 2004 California pediatric West Nile virus case series. Pediatr Infect Dis J 2006;25(1):81–4.
    doi: 10.1097/01.inf.0000195612.04911.b2pubmed: 16395112google scholar: lookup
  27. Rabe IB, Schwartz BS, Farnon EC, Josephson SA, Webber AB, Roberts JP. Fatal transplant-associated west nile virus encephalitis and public health investigation-california, 2010. Transplantation 2013;96(5):463–8.
    doi: 10.1097/TP.0b013e31829b4142pmc: PMC5679220pubmed: 23823653google scholar: lookup
  28. Patel CB, Trikamji BV, Mathisen GE, Mishra SK. Southern California neuroinvasive West Nile virus case series. Neurol Sci 2018;39(2):251–7.
    doi: 10.1007/s10072-017-3164-6pubmed: 29119349google scholar: lookup
  29. Hartley DM, Barker CM, Le Menach A, Niu T, Gaff HD, Reisen WK. Effects of temperature on emergence and seasonality of West Nile virus in California. Am J Trop Med Hyg 2012;86(5):884–94.
    doi: 10.4269/ajtmh.2012.11-0342pmc: PMC3335698pubmed: 22556092google scholar: lookup
  30. Kothera L, Nelms BM, Reisen WK, Savage HM. Population genetic and admixture analyses of Culex pipiens complex (Diptera: Culicidae) populations in California, United States. Am J Trop Med Hyg 2013;89(6):1154–67.
    doi: 10.4269/ajtmh.13-0040pmc: PMC3854894pubmed: 23958909google scholar: lookup
  31. Nelms BM, Kothera L, Thiemann T, Macedo PA, Savage HM, Reisen WK. Phenotypic variation among Culex pipiens complex (Diptera: Culicidae) populations from the Sacramento Valley, California: horizontal and vertical transmission of West Nile virus, diapause potential, autogeny, and host selection. Am J Trop Med Hyg 2013;89(6):1168–78.
    doi: 10.4269/ajtmh.13-0219pmc: PMC3854895pubmed: 24043690google scholar: lookup
  32. Kwan JL, Kluh S, Madon MB, Nguyen DV, Barker CM, Reisen WK. Sentinel chicken seroconversions track tangential transmission of West Nile virus to humans in the greater Los Angeles area of California. Am J Trop Med Hyg 2010;83(5):1137–45.
    doi: 10.4269/ajtmh.2010.10-0078pmc: PMC2963985pubmed: 21036853google scholar: lookup
  33. Kwan JL, Kluh S, Madon MB, Reisen WK. West Nile virus emergence and persistence in Los Angeles, California, 2003–2008. Am J Trop Med Hyg 2010;83(2):400–12.
    doi: 10.4269/ajtmh.2010.10-0076pmc: PMC2911193pubmed: 20682890google scholar: lookup
  34. Kwan JL, Kluh S, Reisen WK. Antecedent avian immunity limits tangential transmission of West Nile virus to humans. PLoS One 2012;7(3):e34127.
    doi: 10.1371/journal.pone.0034127pmc: PMC3311586pubmed: 22457819google scholar: lookup
  35. Kwan JL, Park BK, Carpenter TE, Ngo V, Civen R, Reisen WK. Comparison of enzootic risk measures for predicting West Nile disease, Los Angeles, California, USA, 2004–2010. Emerg Infect Dis 2012;18(8):1298–306.
    doi: 10.3201/eid1808.111558pmc: PMC3414020pubmed: 22840314google scholar: lookup
  36. Carney RM, Ahearn SC, McConchie A, Glasner C, Jean C, Barker C. Early warning system for West Nile virus risk areas, California, USA. Emerg Infect Dis 2011;17(8):1445–54.
    doi: 10.3201/eid1708.100411pmc: PMC3381548pubmed: 21801622google scholar: lookup
  37. Lothrop HD, Lothrop BB, Gomsi DE, Reisen WK. Intensive early season adulticide applications decrease arbovirus transmission throughout the Coachella Valley, Riverside County, California. Vector Borne Zoonotic Dis 2008;8(4):475–89.
    doi: 10.1089/vbz.2007.0238pmc: PMC2978539pubmed: 18494603google scholar: lookup
  38. Reisen WK, Takahashi RM, Carroll BD, Quiring R. Delinquent mortgages, neglected swimming pools, and West Nile virus, California. Emerg Infect Dis 2008;14(11):1747–9.
    doi: 10.3201/eid1411.080719pmc: PMC2630753pubmed: 18976560google scholar: lookup
  39. Reisen WK, Padgett K, Fang Y, Woods L, Foss L, Anderson J. Chronic infections of West Nile virus detected in California dead birds. Vector Borne Zoonotic Dis 2013;13(6):401–5.
    doi: 10.1089/vbz.2012.1097pmc: PMC3669600pubmed: 23488452google scholar: lookup
  40. CalSurv. California Vectorborne Disease Surveillance Gateway, 2018. .
  41. Council of State and Territorial Epidemiologists. CSTE Position Statement 14-ID-04: Arboviral Diseases, Neuroinvasvie and Non-Neuroinvasive 2015 Case Definition. .
  42. Lustig Y, Sofer D, Bucris ED, Mendelson E. Surveillance and Diagnosis of West Nile Virus in the Face of Flavivirus Cross-Reactivity. Front Microbiol 2018;9:2421.
    doi: 10.3389/fmicb.2018.02421pmc: PMC6194321pubmed: 30369916google scholar: lookup
  43. Barzon L, Pacenti M, Ulbert S, Palu G. Latest developments and challenges in the diagnosis of human West Nile virus infection. Expert Rev Anti Infect Ther 2015;13(3):327–42.
    doi: 10.1586/14787210.2015.1007044pubmed: 25641365google scholar: lookup
  44. Sambri V, Capobianchi MR, Cavrini F, Charrel R, Donoso-Mantke O, Escadafal C. Diagnosis of West Nile virus human infections: overview and proposal of diagnostic protocols considering the results of external quality assessment studies. Viruses 2013;5(10):2329–48.
    doi: 10.3390/v5102329pmc: PMC3814591pubmed: 24072061google scholar: lookup
  45. Chiles RE, Green EN, Fang Y, Goddard L, Roth A, Reisen WK. Blinded laboratory comparison of the in situ enzyme immunoassay, the VecTest wicking assay, and a reverse transcription-polymerase chain reaction assay to detect mosquitoes infected with West Nile and St. Louis encephalitis viruses. J Med Entomol 2004;41(4):539–44.
    doi: 10.1603/0022-2585-41.4.539pubmed: 15311443google scholar: lookup
  46. Brault AC, Fang Y, Reisen WK. Multiplex qRT-PCR for the Detection of Western Equine Encephalomyelitis, St. Louis Encephalitis, and West Nile Viral RNA in Mosquito Pools (Diptera: Culicidae). J Med Entomol 2015;52(3):491–9.
    doi: 10.1093/jme/tjv021pmc: PMC4581483pubmed: 26334826google scholar: lookup
  47. Lanciotti RS, Kerst AJ, Nasci RS, Godsey MS, Mitchell CJ, Savage HM. Rapid detection of west nile virus from human clinical specimens, field-collected mosquitoes, and avian samples by a TaqMan reverse transcriptase-PCR assay. J Clin Microbiol 2000;38(11):4066–71.
    doi: 10.1128/JCM.38.11.4066-4071.2000pmc: PMC87542pubmed: 11060069google scholar: lookup
  48. Shi PY, Kauffman EB, Ren P, Felton A, Tai JH, Dupuis AP 2nd. High-throughput detection of West Nile virus RNA. J Clin Microbiol 2001;39(4):1264–71.
    doi: 10.1128/JCM.39.4.1264-1271.2001pmc: PMC87922pubmed: 11283039google scholar: lookup
  49. Burkhalter KL, Lindsay R, Anderson R, Dibernardo A, Fong W, Nasci RS. Evaluation of commercial assays for detecting West Nile virus antigen. J Am Mosq Control Assoc 2006;22(1):64–9.
    doi: 10.2987/8756-971X(2006)22[64:EOCAFD]2.0.CO;2pubmed: 16646324google scholar: lookup
  50. McCaughey KM S., Woods L.. West Nile virus dead bird surveillance program. Proceedings and Papers of the Annual Conference of the California Mosquito and Vector Control Association 2003;71:38–43.
  51. California Department of Public Health, Vector-Borne Disease Section. California West Nile Virus Website, 2019. .
  52. Shi PY, Kramer LD. Molecular detection of West Nile virus RNA. Expert Rev Mol Diagn 2003;3(3):357–66.
    doi: 10.1586/14737159.3.3.357pubmed: 12779009google scholar: lookup
  53. Foss L, Padgett K, Reisen WK, Kjemtrup A, Ogawa J, Kramer V. West Nile Virus-Related Trends in Avian Mortality in California, USA, 2003–12. J Wildl Dis 2015;51(3):576–88.
    doi: 10.7589/2014-06-144pubmed: 25919466google scholar: lookup
  54. Padgett KA, Cahoon-Young B, Carney R, Woods L, Read D, Husted S. Field and laboratory evaluation of diagnostic assays for detecting West Nile virus in oropharyngeal swabs from California wild birds. Vector Borne Zoonotic Dis 2006;6(2):183–91.
    doi: 10.1089/vbz.2006.6.183pubmed: 16796516google scholar: lookup
  55. Foss L, Reisen WK, Fang Y, Kramer V, Padgett K. Evaluation of Nucleic Acid Preservation Cards for West Nile Virus Testing in Dead Birds. PLoS One 2016;11(6):e0157555.
    doi: 10.1371/journal.pone.0157555pmc: PMC4920385pubmed: 27341492google scholar: lookup
  56. Angenvoort J, Brault AC, Bowen RA, Groschup MH. West Nile viral infection of equids. Vet Microbiol 2013;167(1–2):168–80.
    doi: 10.1016/j.vetmic.2013.08.013pmc: PMC4581842pubmed: 24035480google scholar: lookup
  57. Reisen W, Lin J, Presser SB, Enge B, Hardy JL. Evaluation of new methods for sampling sentinel chickens for antibodies to WEE and SLE viruses. Proceedings of the California Mosquito and Vector Control Association 1993;61:33–6.
  58. Reisen WK, Presser SB, Lin J, Enge B, Hardy JL, Emmons RW. Viremia and serological responses in adult chickens infected with western equine encephalomyelitis and St. Louis encephalitis viruses. J Am Mosq Control Assoc 1994;10(4):549–55.
    pubmed: 7707063
  59. Oceguera LF 3rd, Patiris PJ, Chiles RE, Busch MP, Tobler LH, Hanson CV. Flavivirus serology by Western blot analysis. Am J Trop Med Hyg 2007;77(1):159–63.
    pubmed: 17620648
  60. Barker C, Kramer V, Reisen W. Decision support system for mosquito and arbovirus control in California. Earthzine 2010.
  61. Padgett KA, Reisen WK, Kahl-Purcell N, Fang Y, Cahoon-Young B, Carney R. West Nile virus infection in tree squirrels (Rodentia: Sciuridae) in California, 2004–2005. Am J Trop Med Hyg 2007;76(5):810–3.
    pmc: PMC1939863pubmed: 17488896
  62. Institute Sas. SAS/STAT 13.2 User's Guide: High Performance Procedures. Cary, NC: SAS Institute, Inc; 2014.
  63. State of California, Department of Finance. E-1 Population Estimates for Cities, Counties, and the State with Annual Percentage Change—January 1, 2016 and 2017. Sacramento, California, 2017.
  64. Barker CM. Models and Surveillance Systems to Detect and Predict West Nile Virus Outbreaks. J Med Entomol 2019.
    doi: 10.1093/jme/tjz150pubmed: 31549727google scholar: lookup
  65. Lennette EH, Longshore WA. Western equine and St. Louis encephalitis in man, California, 1945–1950. Calif Med 1951;75(3):189–95.
    pmc: PMC1521027pubmed: 14870034
  66. Reeves WC. Clinical and subclinical disease in man. Sacramento, California: California Mosquito and Vector Control Association, Inc.; 1990. p. 1–25.
  67. Reisen WK, Barker CM, Carney R, Lothrop HD, Wheeler SS, Wilson JL. Role of corvids in epidemiology of west Nile virus in southern California. J Med Entomol 2006;43(2):356–67.
    doi: 10.1603/0022-2585(2006)043[0356:rocieo]2.0.co;2pubmed: 16619622google scholar: lookup
  68. Nelms BM, Fechter-Leggett E, Carroll BD, Macedo P, Kluh S, Reisen WK. Experimental and natural vertical transmission of West Nile virus by California Culex (Diptera: Culicidae) mosquitoes. J Med Entomol 2013;50(2):371–8.
    doi: 10.1603/me12264pubmed: 23540126google scholar: lookup
  69. Southam CM, Moore AE. Anti-virus antibody studies following induced infection of man with West Nile, Ilheus, and other viruses. J Immunol 1954;72(6):446–62.
    pubmed: 13174809
  70. Busch MP, Wright DJ, Custer B, Tobler LH, Stramer SL, Kleinman SH. West Nile virus infections projected from blood donor screening data, United States, 2003. Emerg Infect Dis 2006;12(3):395–402.
    doi: 10.3201/eid1205.051287pmc: PMC3291460pubmed: 16704775google scholar: lookup
  71. Carson PJ, Borchardt SM, Custer B, Prince HE, Dunn-Williams J, Winkelman V. Neuroinvasive disease and West Nile virus infection, North Dakota, USA, 1999–2008. Emerg Infect Dis 2012;18(4):684–6.
    doi: 10.3201/eid1804.111313pmc: PMC3309699pubmed: 22469465google scholar: lookup
  72. Lindsey NP, Lehman JA, Staples JE, Fischer M. West Nile Virus and Other Nationally Notifiable Arboviral Diseases—United States, 2014. MMWR Morb Mortal Wkly Rep 2015;64(34):929–34.
    doi: 10.15585/mmwr.mm6434a1pubmed: 26334477google scholar: lookup
  73. U.S. Centers for Disease Control and Prevention, Division of Vector-Borne Diseases. Lyme Disease: Data and Surveillance. CDC; 2019.
  74. Curren EJ, Lindsey NP, Fischer M, Hills SL. St. Louis Encephalitis Virus Disease in the United States, 2003–2017. Am J Trop Med Hyg 2018;99(4):1074–9.
    doi: 10.4269/ajtmh.18-0420pmc: PMC6159600pubmed: 30182919google scholar: lookup
  75. Kilpatrick AM, Pape WJ. Predicting human West Nile virus infections with mosquito surveillance data. Am J Epidemiol 2013;178(5):829–35.
    doi: 10.1093/aje/kwt046pmc: PMC3755645pubmed: 23825164google scholar: lookup
  76. De Angelis D, Presanis AM, Birrell PJ, Tomba GS, House T. Four key challenges in infectious disease modelling using data from multiple sources. Epidemics 2015;10:83–7.
    doi: 10.1016/j.epidem.2014.09.004pmc: PMC4383805pubmed: 25843390google scholar: lookup
  77. Ritz B, Tager I, Balmes J. Can lessons from public health disease surveillance be applied to environmental public health tracking?. Environ Health Perspect 2005;113(3):243–9.
    doi: 10.1289/ehp.7450pmc: PMC1253746pubmed: 15743709google scholar: lookup
  78. Dicker R, U.S. Centers for Disease Control and Prevention. Principles of epidemiology in public health practice: an introduction to applied epidemiology and biostatistics. 2006.
  79. Marier R. The reporting of communicable diseases. Am J Epidemiol 1977;105(6):587–90.
    doi: 10.1093/oxfordjournals.aje.a112424pubmed: 868863google scholar: lookup
  80. Sickbert-Bennett EE, Weber DJ, Poole C, MacDonald PD, Maillard JM. Completeness of communicable disease reporting, North Carolina, USA, 1995–1997 and 2000–2006. Emerg Infect Dis 2011;17(1):23–9.
    doi: 10.3201/eid1701.100660pmc: PMC3204630pubmed: 21192850google scholar: lookup
  81. Campos-Outcalt D, England R, Porter B. Reporting of communicable diseases by university physicians. Public Health Rep 1991;106(5):579–83.
    pmc: PMC1580304pubmed: 1910194
  82. Doyle TJ, Glynn MK, Groseclose SL. Completeness of notifiable infectious disease reporting in the United States: an analytical literature review. Am J Epidemiol 2002;155(9):866–74.
    doi: 10.1093/aje/155.9.866pubmed: 11978592google scholar: lookup
  83. Meyer TE, Bull LM, Cain Holmes K, Pascua RF, Travassos da Rosa A, Gutierrez CR. West Nile virus infection among the homeless, Houston, Texas. Emerg Infect Dis 2007;13(10):1500–3.
    doi: 10.3201/eid1310.070442pmc: PMC2851536pubmed: 18257995google scholar: lookup
  84. Murray K, Baraniuk S, Resnick M, Arafat R, Kilborn C, Cain K. Risk factors for encephalitis and death from West Nile virus infection. Epidemiol Infect 2006;134(6):1325–32.
    doi: 10.1017/S0950268806006339pmc: PMC2870518pubmed: 16672108google scholar: lookup
  85. Ronca SE, Murray KO, Nolan MS. Cumulative Incidence of West Nile Virus Infection, Continental United States, 1999–2016. Emerg Infect Dis 2019;25(2):325–7.
    doi: 10.3201/eid2502.180765pmc: PMC6346444pubmed: 30666940google scholar: lookup
  86. Moreno-Madrinan MJ, Turell M. History of Mosquitoborne Diseases in the United States and Implications for New Pathogens. Emerg Infect Dis 2018;24(5):821–6.
    doi: 10.3201/eid2405.171609pmc: PMC5938790pubmed: 29664379google scholar: lookup
  87. Nielsen CF, Reisen WK, Armijos MV, Maclachlan NJ, Scott TW. High subclinical West Nile virus incidence among nonvaccinated horses in northern California associated with low vector abundance and infection. Am J Trop Med Hyg 2008;78(1):45–52.
    pubmed: 18187784
  88. Gujral IB, Zielinski-Gutierrez EC, LeBailly A, Nasci R. Behavioral risks for West Nile virus disease, northern Colorado, 2003. Emerg Infect Dis 2007;13(3):419–25.
    doi: 10.3201/eid1303.060941pmc: PMC2725886pubmed: 17552095google scholar: lookup
  89. Wheeler SS, Barker CM, Fang Y, Armijos MV, Carroll BD, Husted S. Differential Impact of West Nile Virus on California Birds. Condor 2009;111(1):1–20.
    doi: 10.1525/cond.2009.080013pmc: PMC2892874pubmed: 20589226google scholar: lookup
  90. Thiemann TC, Lemenager DA, Kluh S, Carroll BD, Lothrop HD, Reisen WK. Spatial variation in host feeding patterns of Culex tarsalis and the Culex pipiens complex (Diptera: Culicidae) in California. J Med Entomol 2012;49(4):903–16.
    doi: 10.1603/me11272pmc: PMC3542768pubmed: 22897051google scholar: lookup
  91. Thiemann TC, Wheeler SS, Barker CM, Reisen WK. Mosquito host selection varies seasonally with host availability and mosquito density. PLoS Negl Trop Dis 2011;5(12):e1452.
    doi: 10.1371/journal.pntd.0001452pmc: PMC3243726pubmed: 22206038google scholar: lookup
  92. Hadfield J, Brito AF, Swetnam DM, Vogels CBF, Tokarz RE, Andersen KG. Twenty years of West Nile virus spread and evolution in the Americas visualized by Nextstrain. PLoS Pathog 2019;15(10):e1008042.
    doi: 10.1371/journal.ppat.1008042pmc: PMC6822705pubmed: 31671157google scholar: lookup
  93. Beasley DW, Davis CT, Guzman H, Vanlandingham DL, Travassos da Rosa AP, Parsons RE. Limited evolution of West Nile virus has occurred during its southwesterly spread in the United States. Virology 2003;309(2):190–5.
    doi: 10.1016/s0042-6822(03)00150-8pubmed: 12758166google scholar: lookup
  94. Di Giallonardo F, Geoghegan JL, Docherty DE, McLean RG, Zody MC, Qu J. Fluid Spatial Dynamics of West Nile Virus in the United States: Rapid Spread in a Permissive Host Environment. J Virol 2016;90(2):862–72.
    doi: 10.1128/JVI.02305-15pmc: PMC4702690pubmed: 26512086google scholar: lookup

Citations

This article has been cited 15 times.
  1. Russell MC, Bliss DA, Fischer GA, Riehle MA, Rappazzo KM, Ernst KC, Hilborn ED, DeFlorio-Barker S, Combrink L. Evaluating Associations Between Drought and West Nile Virus Epidemics: A Systematic Review. Microorganisms 2025 Dec 15;13(12).
    doi: 10.3390/microorganisms13122851pubmed: 41472054google scholar: lookup
  2. Sambado S, Sipin TJ, Rennie Z, Larsen A, Cunningham J, Quandt A, Sousa D, MacDonald AJ. The paradoxical impact of drought on West Nile virus risk: insights from long-term ecological data. Proc Biol Sci 2025 Sep;292(2054):20251365.
    doi: 10.1098/rspb.2025.1365pubmed: 40897323google scholar: lookup
  3. MacDonald AJ, Sousa D, Quandt A, Sambado S, Sipin TJ, Rennie Z, Larsen AE. Extreme climate whiplash events drive divergent responses of mosquito-borne disease. PNAS Nexus 2025 Aug;4(8):pgaf223.
    doi: 10.1093/pnasnexus/pgaf223pubmed: 40757237google scholar: lookup
  4. Tavares Y, Day J, Giordano BV, Eastmond B, Burkett-Cadena N, Guralnick RP, Martin E, Campbell LP. Regional variation in the landscape ecology of West Nile virus sentinel chicken seroconversion in Florida. PLoS One 2024;19(10):e0305510.
    doi: 10.1371/journal.pone.0305510pubmed: 39453894google scholar: lookup
  5. Parker N. Exploring the role of temperature and other environmental factors in West Nile virus incidence and prediction in California counties from 2017-2022 using a zero-inflated model. PLoS Negl Trop Dis 2024 Jun;18(6):e0012051.
    doi: 10.1371/journal.pntd.0012051pubmed: 38913741google scholar: lookup
  6. Foss L, Feiszli T, Kramer VL, Reisen WK, Padgett K. Epidemic versus endemic West Nile virus dead bird surveillance in California: Changes in sensitivity and focus. PLoS One 2023;18(4):e0284039.
    doi: 10.1371/journal.pone.0284039pubmed: 37023091google scholar: lookup
  7. Beissinger SR, Peterson SM, Hall LA, Van Schmidt N, Tecklin J, Risk BB, Richmond OM, Kovach TJ, Kilpatrick AM. Stability of patch-turnover relationships under equilibrium and nonequilibrium metapopulation dynamics driven by biogeography. Ecol Lett 2022 Nov;25(11):2372-2383.
    doi: 10.1111/ele.14111pubmed: 36209497google scholar: lookup
  8. Danforth ME, Snyder RE, Feiszli T, Bullick T, Messenger S, Hanson C, Padgett K, Coffey LL, Barker CM, Reisen WK, Kramer VL. Epidemiologic and environmental characterization of the Re-emergence of St. Louis Encephalitis Virus in California, 2015-2020. PLoS Negl Trop Dis 2022 Aug;16(8):e0010664.
    doi: 10.1371/journal.pntd.0010664pubmed: 35939506google scholar: lookup
  9. McNeil C, Verlander S, Divi N, Smolinski M. The Landscape of Participatory Surveillance Systems Across the One Health Spectrum: Systematic Review. JMIR Public Health Surveill 2022 Aug 5;8(8):e38551.
    doi: 10.2196/38551pubmed: 35930345google scholar: lookup
  10. Danforth ME, Snyder RE, Lonstrup ETN, Barker CM, Kramer VL. Evaluation of the effectiveness of the California mosquito-borne virus surveillance & response plan, 2009-2018. PLoS Negl Trop Dis 2022 May;16(5):e0010375.
    doi: 10.1371/journal.pntd.0010375pubmed: 35533207google scholar: lookup
  11. Trout Fryxell RT, Camponovo M, Smith B, Butefish K, Rosenberg JM, Andsager JL, Day CA, Willis MP. Development of a Community-Driven Mosquito Surveillance Program for Vectors of La Crosse Virus to Educate, Inform, and Empower a Community. Insects 2022 Feb 3;13(2).
    doi: 10.3390/insects13020164pubmed: 35206737google scholar: lookup
  12. Metzger ME, Wekesa JW, Kluh S, Fujioka KK, Saviskas R, Arugay A, McConnell N, Nguyen K, Krueger L, Hacker GM, Hu R, Kramer VL. Detection and Establishment of Aedes notoscriptus (Diptera: Culicidae) Mosquitoes in Southern California, United States. J Med Entomol 2022 Jan 12;59(1):67-77.
    doi: 10.1093/jme/tjab165pubmed: 34617571google scholar: lookup
  13. Warang A, Zhang M, Zhang S, Shen Z. A panel of real-time PCR assays for the detection of Bourbon virus, Heartland virus, West Nile virus, and Trypanosoma cruzi in major disease-transmitting vectors. J Vet Diagn Invest 2021 Nov;33(6):1115-1122.
    doi: 10.1177/10406387211039549pubmed: 34414840google scholar: lookup
  14. Danforth ME, Fischer M, Snyder RE, Lindsey NP, Martin SW, Kramer VL. Characterizing Areas with Increased Burden of West Nile Virus Disease in California, 2009-2018. Vector Borne Zoonotic Dis 2021 Aug;21(8):620-627.
    doi: 10.1089/vbz.2021.0014pubmed: 34077676google scholar: lookup
  15. Ogunlade ST, Meehan MT, Adekunle AI, Rojas DP, Adegboye OA, McBryde ES. A Review: Aedes-Borne Arboviral Infections, Controls and Wolbachia-Based Strategies. Vaccines (Basel) 2021 Jan 8;9(1).
    doi: 10.3390/vaccines9010032pubmed: 33435566google scholar: lookup
Subscribe to our newsletter
Join 99,970 horse owners like you who receive our email updates on horse health and nutrition.