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Home / Equine Research Bank / PLoS Negl Trop Dis / West Nile virus in California, 2003-2018: A persistent threa...
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.
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Publication Date: 2020-11-18 PubMed ID: 33206634PubMed Central: PMC7710070DOI: 10.1371/journal.pntd.0008841Google Scholar: Lookup
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  • Journal Article
  • Research Support
  • N.I.H.
  • Extramural
  • Research Support
  • U.S. Gov't
  • Non-P.H.S.
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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.

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