Abstract
We have identified environmental and demographic variables, available in January, that predict the relative magnitude and spatial distribution of West Nile virus (WNV) for the following summer. The yearly magnitude and spatial distribution for WNV incidence in humans in the United States (US) have varied wildly in the past decade. Mosquito control measures are expensive and having better estimates of the expected relative size of a future WNV outbreak can help in planning for the mitigation efforts and costs. West Nile virus is spread primarily between mosquitoes and birds; humans are an incidental host. Previous efforts have demonstrated a strong correlation between environmental factors and the incidence of WNV. A predictive model for human cases must include both the environmental factors for the mosquito-bird epidemic and an anthropological model for the risk of humans being bitten by a mosquito. Using weather data and demographic data available in January for every county in the US, we use logistic regression analysis to predict the probability that the county will have at least one WNV case the following summer. We validate our approach and the spatial and temporal WNV incidence in the US from 2005 to 2013. The methodology was applied to forecast the 2014 WNV incidence in late January 2014. We find the most significant predictors for a county to have a case of WNV to be the mean minimum temperature in January, the deviation of this minimum temperature from the expected minimum temperature, the total population of the county, publicly available samples of local bird populations, and if the county had a case of WNV the previous year.
Highlights
West Nile virus (WNV) is a mosquito-borne flavivirus first identified in Uganda in 1937
In 2012, the USA experienced one of the worst years on record for human WNV 1, with a higher than expected number of 5,674 cases reported to the CDC 2; this is in contrast to the three-year period from 2009 to 2011, during which a total of 3,809 cases were reported
Laboratory and field studies have shown that WNV transmission is associated with environmental factors such as temperature, precipitation, drought, and land use, as well as biological factors such as bird community structure and anthropological variables, including urbanization and human density 8,45
Summary
West Nile virus (WNV) is a mosquito-borne flavivirus first identified in Uganda in 1937. WNV continues to be a public health hazard in the continental United States 13 years after its introduction into New York City in 1999 where it initially caused significant bird mortality and neuroinvasive disease (NID) in humans. In 2012, 2,873 NID cases were reported from 976 counties across the 48 contiguous states, the District of Colombia and Puerto Rico. There were 270 fatalities among the NID cases 3. About 20-30% of the people infected with WNV develop symptoms and less than 1% of people infected develop NID. The states with the highest incidence of WNV in 2012 were North and South Dakota, Louisiana, Texas, and Mississippi, indicating a large geographic range of intense transmission that year 3
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
