West Nile Virus Surveillance Program

General Information

Mosquitoes acquire the virus from infected birds and pass it on to other birds, animals and people.

Horses become infected with West Nile virus after being bitten by an infected mosquito. There is no evidence that horses can transmit the West Nile virus to other horses, birds or people. 

( View the transmission cycle of WNV.)

Although the chances of a person becoming ill are small, there are some simple steps you can take to reduce them even further.  The Nebraska Department of Health and Human Services has created this web site to give you the information you need to reduce the number of mosquitoes in your yard, neighborhood and community; and to help reduce the need for more aggressive mosquito control, such as the spraying of insecticides.

Mosquito Facts

Mosquitoes are small flying insects that feed on human and animal blood or plant juices.  Only female mosquitoes bite to get a blood meal to develop eggs.  Mosquitoes are generally considered a nuisance pest, and occasionally can transmit disease.  While there are approximately 50 different species of mosquitoes in Nebraska, most mosquitoes do not transmit West Nile virus.

Where They Live and Breed

Many types of mosquitoes lay their eggs in standing water.  Weeds, tall grass and shrubbery provide an outdoor home for adult mosquitoes, which also may enter houses through unscreened windows or doors, or broken screens.  Many mosquitoes will breed in containers that hold water, such as flower pots or discarded tires.

Image of a mosquito laying eggs.


West Nile Virus and Your Health

Mild cases of West Nile infection may include a slight fever and/or headache.  Severe infections are marked by a rapid onset of a high fever, head and body aches, and usually occur five to 15 days after exposure.   There is no specific treatment of viral infections, other than to treat the symptoms and provide supportive care.  Those who are at highest risk of becoming seriously ill from West Nile infection are persons who are over the age of 50.   Healthy children and adults are at very low risk for infection.

When Mosquitoes Are Most Active

Some mosquitoes are most active between dusk and dawn when the air is calm, and that is when the females are most likely to bite.  However, others will feed at any time of day.

Protecting Your Home

PDF Homeowner's Guide to Mosquito Control

Mosquitoes can develop in any standing water that lasts more than 4 days.  To reduce the mosquito population around your home and property, reduce or eliminate all standing water and debris: 

  • Dispose of tin cans, plastic containers, ceramic pots or similar water-holding containers.

  • Clear brush from around your home

  • Remove all discarded tires on your property.  Used tires have become the most common mosquito breeding site in the country.

  • Drill holes in the bottoms of recycling containers that are kept outdoors.

  • Clean clogged roof gutters regularly (spring and fall), particularly if the leaves from surrounding trees have a tendency to plug up the drains. Roof gutters are easily overlooked but can produce millions of mosquitoes each season.

  • Turn over plastic wading pools and wheelbarrows when not in use.

  • Change the water in bird baths

  • Clean vegetation and debris from the edges of ponds.

  • Clean and chlorinate swimming pools, outdoor saunas and hot tubs.

  • Drain water from pool covers.

  • Use landscaping to eliminate stagnant water that collects on your property.


Protecting Yourself

Most mosquitoes in Nebraska do not transmit disease.   Unless you are at high risk for infection, it is not necessary to limit any outdoor activities.  Those who are at highest risk of becoming seriously ill from West Nile infection are the elderly and persons with damaged immune systems.  If West Nile virus is found in Nebraska, persons who are at highest risk should avoid mosquito bites: 

  • Avoid being outdoors at dusk and dawn, the times when mosquitoes are most active.

  • Wear shoes and socks, long pants and a long-sleeved shirt when outdoors for long periods of time.

  • Consider the use of mosquito repellent, according to directions, when it is necessary to be outdoors.

  • Make sure all windows and doors in your home have screens, and that all screens are in good repair. 


Proper Use of DEET

EPA - Mosquito Control

DEET - - the chemical N, N-diethyl-m-toluamide   - is an insect repellent that can reduce the risk of mosquito bites but must be used with caution. 

DEET is a chemical used in insect repellents. The amount of DEET in insect repellents varies from product to product, so it's important to read the label of any product you buy. The amount of DEET may range from less than 10% to more than 30%.


Studies show that products with higher amounts of DEET protect people longer. For example, products with amounts around 10% may repel pests for about 2 hours, while products with amounts of about 24% last an average of 5 hours. But studies also show that products with amounts of DEET greater than 30% don't offer any extra protection.
Information regarding applying insect repellent to children.
In addition, DHHS recommends the following precautions when using repellents containing DEET:


  • People can and should use both sunscreen and DEET when they are outdoors to protect their health. Follow the instructions on the package for proper application of each product. Apply sunscreen first, followed by repellant containing DEET.

  • Store out of the reach of children and read all instructions on the label before applying.

  • Do NOT allow young children to apply DEET themselves.

  • Do NOT apply DEET directly to children.  Apply to your own hands and then put it on the child.

  • When applying DEET, avoid the child's face and hands.

  • Avoid prolonged and excessive use of DEET.  Use sparingly to cover exposed skin: do NOT treat unexposed skin.

  • Do NOT apply repellents in enclosed areas.

  • Do NOT apply directly to your face.

  • DEET can be applied to clothing, but may damage some synthetic fabrics and plastics.

  • Wash all treated skin and clothing after returning indoors.

  • If you believe you or a child is having an adverse reaction to a repellent containing DEET, wash the treated area immediately and call your health care provider or local poison control center.

Reporting Dead Birds

Keeping track of the number of dead birds helps public health officials monitor the human health risk for West Nile virus.  View instructions on how to report or drop-off a dead bird.

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