Some Mosquitoes Carry Bad News

Safety Talk

Many outdoor workers are at risk for West Nile virus. This virus is fairly new to North America, but it has spread rapidly.

In humans, most West Nile virus infections cause either no symptoms or a mild flu-like illness. Severe infections include high fever, stiff neck, disorientation, tremors, muscle weakness and paralysis. The most severely affected patients may suffer an inflamed brain or brain membranes, or spinal cord or both. Severe cases may be fatal.

Incubation time — from mosquito bite to symptoms — may be from three to 15 days. West Nile virus normally passes between mosquitoes and birds, but a person or animal bitten by an infected mosquito may get it.

Outdoor workers such as farmers, foresters, landscapers, groundskeepers, painters, roofers, pavers and construction workers are most at risk, but activities off the job could expose anyone to the virus.

Do you play outdoor sports or do yard work on days off? If mosquitoes are around, try to avoid being outdoors at times when they bite most actively, usually from dusk to dawn. Some are active during the day —particularly in weedy, brushy, and wooded or shaded areas. If you can’t avoid mosquito areas, wear long-sleeved shirts, long pants and socks. Spray exposed skin with insect repellent.

Bird farm workers have been infected with West Nile virus. Others who could be exposed include veterinarians, emergency response and public safety workers and wildlife biologists. Laboratory workers should use caution when autopsying birds or handling tissues possibly infected with West Nile virus.

West Nile virus may be passed on by organ transplants, blood transfusion or possibly breast milk. Mother-to-fetus infection has occurred. However, an infected mosquito’s bite is the most common route to infection.

People over 50 years of age face the highest risk of severe West Nile illness, but all workers should follow precautions.

Here’s what you can do to avoid West Nile virus:

• Clean up potential breeding grounds for mosquitoes which include areas of standing water. Remove discarded tires from wherever you work or play. Turn over, cover or empty buckets, barrels, wheelbarrows or tarps. Any puddle or ditch filled with standing water for more than four days gives mosquitoes a breeding place, so change water in animals’ drinking troughs every few days and aerate ponds. Remove debris from rain gutters.
• Pregnant women particularly should avoid mosquitoes and wear protective clothing.
• You may be advised to use an insect repellent containing DEET (N,N-diethyl-m-toluamide or N,N-diethyl-3-methylbenzamide), according to manufacturers’ directions.
• Anyone handling dead animals should wear appropriate gloves such as medical examination gloves. Cotton, leather and other absorbent materials do not protect you from exposure to blood and other body fluids.
• Help government agencies tracking the virus by reporting dead birds and infected horses. Notify your supervisor or local health department.

Find out about how likely you are to encounter West Nile virus in your area or job, and learn how to protect yourself.