Characterizing Areas with Increased Burden of West Nile Virus Disease in California, 2009–2018

Danforth, Mary E.; Fischer, Marc; Snyder, Robert E.; Lindsey, Nicole P.; Martin, Stacey W.; Kramer, Vicki L.

doi:10.1089/vbz.2021.0014

Cited by 5 publications

(6 citation statements)

References 29 publications

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“…WNND is most likely to be diagnosed and reported, due to its severity of disease, but it is estimated that fewer than 5% of non-neuroinvasive disease cases are diagnosed and reported [ 2 , 19 ]. For every neuroinvasive disease case, there are an estimated 30–70 non-neuroinvasive cases, which means the true annual incidence of WNV in California is between 19 and 45 cases per 100,000 people [ 21 ], considerably higher than the observed incidence of 1.1 cases per 100,000 during this time-period [ 23 ]. WNV reporting is also likely influenced by additional factors such as access to healthcare and socio-economic status, which could lead to underreporting from some areas.…”

Section: Discussionmentioning

confidence: 99%

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Evaluation of the effectiveness of the California mosquito-borne virus surveillance & response plan, 2009–2018

Danforth

Snyder²,

Lonstrup³

et al. 2022

PLoS Negl Trop Dis

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Local vector control and public health agencies in California use the California Mosquito-Borne Virus Surveillance and Response Plan to monitor and evaluate West Nile virus (WNV) activity and guide responses to reduce the burden of WNV disease. All available data from environmental surveillance, such as the abundance and WNV infection rates in Culex tarsalis and the Culex pipiens complex mosquitoes, the numbers of dead birds, seroconversions in sentinel chickens, and ambient air temperatures, are fed into a formula to estimate the risk level and associated risk of human infections. In many other areas of the US, the vector index, based only on vector mosquito abundance and infection rates, is used by vector control programs to estimate the risk of human WNV transmission. We built models to determine the association between risk level and the number of reported symptomatic human disease cases with onset in the following three weeks to identify the essential components of the risk level and to compare California’s risk estimates to vector index. Risk level calculations based on Cx. tarsalis and Cx. pipiens complex levels were significantly associated with increased human risk, particularly when accounting for vector control area and population, and were better predictors than using vector index. Including all potential environmental components created an effective tool to estimate the risk of WNV transmission to humans in California.

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Section: Discussionmentioning

confidence: 99%

“…California reported 4,035 (18%) of all US cases, more than any other state, and disproportionate to its 12% of the nation’s population [ 21 , 22 ]. The majority of California’s cases have occurred in Southern California and the Central Valley [ 21 , 23 ].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the effectiveness of the California mosquito-borne virus surveillance & response plan, 2009–2018

Danforth

Snyder²,

Lonstrup³

et al. 2022

PLoS Negl Trop Dis

Self Cite

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“…Many of the top ten counties for dead bird reports in either time period had the greatest number of human WNV cases in 2009–2018 [ 64 ]: Fresno, Los Angeles, Orange, Riverside, Sacramento, San Bernardino, and Stanislaus. This suggests that dead bird reporting activity generally occurs in the same regions where human WNV cases occur, making dead birds a relevant WNV surveillance tool.…”

Section: Discussionmentioning

confidence: 99%

Epidemic versus endemic West Nile virus dead bird surveillance in California: Changes in sensitivity and focus

et al. 2023

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Since 2003, the California West Nile virus (WNV) dead bird surveillance program (DBSP) has monitored publicly reported dead birds for WNV surveillance and response. In the current paper, we compared DBSP data from early epidemic years (2004–2006) with recent endemic years (2018–2020), with a focus on specimen collection criteria, county report incidence, bird species selection, WNV prevalence in dead birds, and utility of the DBSP as an early environmental indicator of WNV. Although fewer agencies collected dead birds in recent years, most vector control agencies with consistent WNV activity continued to use dead birds as a surveillance tool, with streamlined operations enhancing efficiency. The number of dead bird reports was approximately ten times greater during 2004–2006 compared to 2018–2020, with reports from the Central Valley and portions of Southern California decreasing substantially in recent years; reports from the San Francisco Bay Area decreased less dramatically. Seven of ten counties with high numbers of dead bird reports were also high human WNV case burden areas. Dead corvid, sparrow, and quail reports decreased the most compared to other bird species reports. West Nile virus positive dead birds were the most frequent first indicators of WNV activity by county in 2004–2006, followed by positive mosquitoes; in contrast, during 2018–2020 mosquitoes were the most frequent first indicators followed by dead birds, and initial environmental WNV detections occurred later in the season during 2018–2020. Evidence for WNV impacts on avian populations and susceptibility are discussed. Although patterns of dead bird reports and WNV prevalence in tested dead birds have changed, dead birds have endured as a useful element within our multi-faceted WNV surveillance program.

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“…The chikungunya virus (CHIKV) which re-emerged in Kenya in 2004, spread like a wild fire causing large-scale outbreaks with high morbidity in several countries of Asia, Europe, Oceania, the Caribbeans and the South and North Americas [1,2]. Similar is the case with West Nile virus (WNV), that caused massive outbreaks in North America, South America and Europe with high morbidity and mortality, since it was first detected in New York in 1999 [3,4].…”

Section: Introductionmentioning

confidence: 96%

“…Emerging and re-emerging arthropod borne viruses continue to be a major threat to humanity as they not only inflict high morbidity and mortality but also devastate the economy of many countries especially in the tropical and subtropical countries [1][2][3][4]. During the last few decades, mosquito-borne viruses have emerged as a major public health concern, replacing malaria that had the dubious distinction as a major mosquito borne killer disease across the globe.…”

Section: Introductionmentioning

confidence: 99%

Abundance of Phasi-Charoen-like virus in Aedes aegypti mosquito populations in different states of India

et al. 2022

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Mosquitoes are known to harbor a large number of insect specific viruses (ISV) in addition to viruses of public health importance. These ISVs are highly species specific and are non-pathogenic to humans or domestic animals. However, there is a potential threat of these ISVs evolving into human pathogens by genome alterations. Some ISVs are known to modulate replication of pathogenic viruses by altering the susceptibility of vector mosquitoes to pathogenic viruses, thereby either inhibiting or enhancing transmission of the latter. In the present study, we report predominance of Phasi Charoen-like virus (PCLV, Family: Phenuviridae) contributing to >60% of the total reads in Aedes aegypti mosquitoes collected from Pune district of Maharashtra state using next generation sequencing based metagenomic analysis of viromes. Similar results were also obtained with mosquitoes from Assam, Tamil Nadu and Karnataka states of India. Comparison of Pune mosquito sequences with PCLV Rio (Brazil) isolate showed 98.90%, 99.027% and 98.88% homologies in the S, M and L segments respectively indicating less genetic heterogeneity of PCLV. The study also demonstrated occurrence of transovarial transmission as seen by detection of PCLV in eggs, larvae, pupae and male mosquitoes. Ae. aegypti mosquitoes collected from Pune also showed a large number of reads for viruses belonging to Baculoviridae, Rhabdoviridae, Genomoviridae and Bunyaviridae families. The role of PCLV in the replication of dengue and chikungunya virus is yet not clear. It warrants further studies to know the significance of PCLV and other ISVs on the replication and transmission of Ae. aegypti borne pathogenic viruses, especially in the absence of prophylactics or therapeutics.

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Characterizing Areas with Increased Burden of West Nile Virus Disease in California, 2009–2018

Cited by 5 publications

References 29 publications

Evaluation of the effectiveness of the California mosquito-borne virus surveillance & response plan, 2009–2018

Evaluation of the effectiveness of the California mosquito-borne virus surveillance & response plan, 2009–2018

Epidemic versus endemic West Nile virus dead bird surveillance in California: Changes in sensitivity and focus

Abundance of Phasi-Charoen-like virus in Aedes aegypti mosquito populations in different states of India

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