West nile virus risk factors

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

Overview

Risk factors for infection with West Nile virus include:^[1]

Outdoor exposure - While conclusive data are lacking, it is reasonable to infer that persons engaged in extensive outdoor work or recreational activities are at greater risk of being bitten by WNV-infected mosquitoes. Develop opportunities to inform people engaged in outdoor activities about WNV. Encourage use of repellent and protective clothing, particularly if outdoors during evening, night, or early morning hours. Local spokespersons (e.g., union officials, job-site supervisors, golf pros, gardening experts) may be useful collaborators.

Homeless persons - Extensive outdoor exposure and limited financial resources in this group present special challenges. Application of repellents with DEET or permethrin to clothing may be most appropriate for this population. Work with social service groups in your area to reach this population segment.

Persons who live in residences lacking window screens - The absence of intact window/door screens is a likely risk factor for exposure to mosquito bites. Focus attention on the need to repair screens and resources to do so. Partner with community organizations that can assist elderly persons or others with financial or physical barriers to screen installation or repair.

Risk factors for the development of more severe forms of the disease include:

Age > 50 years - While persons of any age can be infected with WNV, US surveillance data indicate that persons over age 50 are at higher risk for severe disease and death due to WNV infection.