West nile virus primary prevention

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Mosquito abatement programs successfully employ integrated pest management (IPM) principles to reduce mosquito abundance, providing important community services to protect quality of life and public health^[1].
Prevention and control of WNV and other zoonotic arboviral diseases is accomplished most effectively through a comprehensive, integrated vector management (IVM) program applying the principles of IPM.
IVM is based on an understanding of the underlying biology of the arbovirus transmission system, and utilizes regular monitoring of vector mosquito populations and WNV activity levels to determine if, when, and where interventions are needed to keep mosquito numbers below levels which produce risk of human disease, and to respond appropriately to reduce risk when it exceeds acceptable levels.
Operationally, IVM is anchored by a monitoring program providing data that describe:

Conditions and habitats that produce vector mosquitoes.
Abundance of those mosquitoes over the course of a season.
WNV transmission activity levels expressed as WNV infection rate in mosquito vectors.
Parameters that influence local mosquito populations and WNV transmission.

These data inform decisions about implementing mosquito control activities appropriate to the situation, such as:

Source reduction through habitat modification.
Larval mosquito control using the appropriate methods for the habitat.
Adult mosquito control using pesticides applied from trucks or aircraft when established thresholds have been exceeded.
Community education efforts related to WNV risk levels and intervention activities.

Monitoring also provides quality control for the program, allowing evaluation of:

Effectiveness of larval control efforts.
Effectiveness of adult control efforts.
Causes of control failures (e.g., undetected larval sources, pesticide resistance, equipment failure).

Effective IVM for WNV prevention relies on a sustained, consistent surveillance program that targets vector species.
The objectives are to identify and map larval production sites by season, monitor adult mosquito abundance, monitor vector infection rates, document the need for control based on established thresholds, and monitor control efficacy.
Surveillance can be subdivided into three categories based on the objective of the surveillance effort; these are: larval mosquito surveillance, adult mosquito surveillance and WWNV transmission activity.
However, the surveillance elements are complementary, and in combination provide the information required for IVM decisions.