1. Comparison of the Efficiency and Cost of West Nile Virus Surveillance Methods in California
- Author
-
Healy, Jessica M, Reisen, William K, Kramer, Vicki L, Fischer, Marc, Lindsey, Nicole P, Nasci, Roger S, Macedo, Paula A, White, Gregory, Takahashi, Richard, Khang, La, and Barker, Christopher M
- Subjects
Epidemiology ,Health Sciences ,Emerging Infectious Diseases ,West Nile Virus ,Rare Diseases ,Vector-Borne Diseases ,Prevention ,Biodefense ,Infectious Diseases ,Vaccine Related ,Infection ,Good Health and Well Being ,Animals ,California ,Chickens ,Costs and Cost Analysis ,Culicidae ,Female ,Humans ,Insect Vectors ,Poultry Diseases ,Prevalence ,RNA ,Viral ,Sentinel Surveillance ,West Nile Fever ,West Nile virus ,Surveillance methods ,Birds ,Cost effectiveness ,Public Health and Health Services ,Tropical Medicine - Abstract
Surveillance systems for West Nile virus (WNV) combine several methods to determine the location and timing of viral amplification. The value of each surveillance method must be measured against its efficiency and costs to optimize integrated vector management and suppress WNV transmission to the human population. Here we extend previous comparisons of WNV surveillance methods by equitably comparing the most common methods after standardization on the basis of spatial sampling density and costs, and by estimating optimal levels of sampling effort for mosquito traps and sentinel chicken flocks. In general, testing for evidence of viral RNA in mosquitoes and public-reported dead birds resulted in detection of WNV approximately 2-5 weeks earlier than serological monitoring of sentinel chickens at equal spatial sampling density. For a fixed cost, testing of dead birds reported by the public was found to be the most cost effective of the methods, yielding the highest number of positive results per $1000. Increased spatial density of mosquito trapping was associated with more precise estimates of WNV infection prevalence in mosquitoes. Our findings also suggested that the most common chicken flock size of 10 birds could be reduced to six to seven without substantial reductions in timeliness or sensitivity. We conclude that a surveillance system that uses the testing of dead birds reported by the public complemented by strategically timed mosquito and chicken sampling as agency resources allow would detect viral activity efficiently in terms of effort and costs, so long as susceptible bird species that experience a high mortality rate from infection with WNV, such as corvids, are present in the area.
- Published
- 2015