What can employers do to reduce

the risk to workers?

Employers should keep in mind that eliminating mosquito breeding grounds is a highly effective way of reducing mosquito populations and the number of mosquito bites.

Mosquitoes lay eggs in standing water.

Employers with workers who work outside,

and in and around areas of stagnant water

should:

• Be aware of working conditions, i.e., the

presence of equipment or areas where

water accumulates.

• Advise workers to inspect work areas and,

where possible, get rid of sources of stagnant or standing water to remove a potential breeding ground of mosquitoes.

• Reduce or eliminate mosquito populations

by disrupting mosquito breeding grounds

(i.e., whenever possible, drain ditches, gutters, etc., to get rid of sources of stagnant

or standing water).

• Advise workers to protect themselves from

skin contact with dead birds. CDC recommends using gloves or an inverted plastic

bag when handling dead birds.

What can workers do to protect

themselves?

It may not always be possible to eliminate

all potential mosquito breeding grounds.

Knowing the key steps to take to minimize

the risk of mosquito bites is important in

reducing the risk of WNV infection. Workers

who work outdoors should be aware that

the use of personal protective equipment

What are the signs and symptoms of

West Nile Virus?

In most cases, persons infected with WNV

either show no symptoms or have very mild

flu-like symptoms, called West Nile fever.

These mild cases of West Nile fever normally

last only a few days and are not believed to

cause any long-term effects. The typical time

from infection to the onset of signs and

symptoms is 3 to 14 days. Signs and symptoms of the milder illness, West Nile fever,

include tiredness, headache, fever, body

aches, swollen lymph nodes, and/or a skin

rash.

According to the Centers for Disease Control

and Prevention (CDC), severe illness is reported to occur in about 1 of every 150 persons

infected with WNV. Symptoms of severe disease may last several weeks and may have

permanent neurological effects. The signs

and symptoms of more severe infection

(West Nile encephalitis or meningitis) include

nausea/vomiting, headache, high fever, stiffness in the neck, disorientation (in very

severe cases, coma), tremors and convulsions, and muscle weakness (in very severe

cases, paralysis). Severe WNV infection is a

medical emergency and persons who

develop symptoms should seek immediate

medical assistance.

How can workers become exposed?

Flooded areas, particularly in warm climates,

provide the opportunity for mosquitoes to

breed in stagnant water. Bites from infected

mosquitoes may result in WNV.

FactSheet

West Nile Virus

West Nile Virus (WNV) infection is an illness transmitted to humans primarily by

mosquitoes. The pathpgen that causes WNV infection is a virus that is known to

infect birds and other animals as well as humans. Outdoor workers are at risk,

particularly in warmer weather (when mosquitoes are more likely to be present).

The following information below is designed to educate employers and workers

on the virus and also offer ways to reduce the risks of infection.
and techniques is essential to preventing

mosquito bites. Workers should:

• Cover as much of the skin as possible by

wearing shirts with long sleeves, long

pants and socks whenever possible. Use

light weight clothing to minimize the

potential for heat-induced illnesses.

• Use insect repellent containing an EPAregistered active ingredient (e.g., DEET,

Picaridin) on exposed skin according to

instructions on packaging. All of the EPAregistered active ingredients have demonstrated repellency however some provide

more long-lasting protection than others.

• Avoid the use of perfumes and colognes

when working outdoors; mosquitoes may

be more attracted to individuals wearing

perfumes or colognes.

• Choose a repellent that provides protection

for the amount of time that you will be outdoors/in areas of concern. The more DEET

a repellent contains, the longer time it can

protect one from mosquito bites, with protection times ranging from 1 hour (4.75%

DEET) to 5 hours (23.8% DEET).

• Spray insect repellent on the outside of

one’s clothing, as it is possible for mosquitoes to bite through thin clothing.

This is one in a series of informational fact sheets highlighting OSHA programs, policies or

standards. It does not impose any new compliance requirements. For a comprehensive list of

compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal

Regulations. This information will be made available to sensory impaired individuals upon request.

The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.

• Do NOT spray insect repellent on skin that

is under clothing.

• Never apply insect repellents over open

wounds or irritated skin.

• Do NOT spray aerosol or pump products in

enclosed areas. Do NOT spray a pump or

aerosol product directly on one’s face. First

spray on hands and carefully rub on face

(do not allow insect repellent to contact

one’s eyes and mouth).

• After working in areas where mosquitoes

are a concern, use soap and water to wash

skin that has been treated with insect repellent.

• Be extra vigilant at dusk and dawn when

mosquitoes are most active.

Additional Resources:

CDC West Nile Virus Home Page at

http://www.cdc.gov/ncidod/dvbid/westnile/

CDC information on the use of insect

repellents at

http://www.cdc.gov/ncidod/dvbid/westnile/qa/

insect_repellent.htm

OSHA at http://www.osha.gov/dts/shib/

shib082903b.html

U.S. Department of Labor

www.osha.gov (800) 321-OSHA (6742)

For more complete information:

DTSEM 09R 2012