Setting the record straight on West Nile virus

Sep 6, 2019, 14:16 PM by Fred Speer

There has been much discussion lately about the threat posed by mosquitoes and West Nile virus (WNV). With confirmed cases in Los Angeles, Clark, your neighborly pest control, termite, and lawn care expert, would like to share some important facts on what West Nile virus is and isn’t, and how Californians can protect themselves and their families.

According to the Centers for Disease Control and Prevention (CDC), a small percentage of people who contract West Nile virus — roughly one in five — develop a fever and experience headaches, body aches, vomiting, diarrhea, or a rash. Even rarer, about one in 150 people who are infected with West Nile virus can develop a serious illness, such as inflammation of the spinal cord or brain.

Milder cases of West Nile virus (e.g., with such symptoms as fever, headache, body aches, nausea) improve without treatment, and people do not necessarily need to seek medical attention, although you may choose to do so. If you develop more serous symptoms, such as unusually severe headaches or confusion, seek medical attention immediately.

What is West Nile virus?

West Nile virus is a mosquito-borne disease that was originally found in Africa. It was first detected in the eastern United States in1999. Since then, the virus has spread across the continental United States and is well established in most states, including California.

How do you get West Nile virus?

In most cases, WNV is spread by the bite of an infected mosquito. Mosquitoes are WNV carriers (vectors) that become infected when they feed on infected birds. Infected mosquitoes can then spread WNV to humans and other animals when they bite.

What type of mosquito spreads West Nile virus?

The main species of mosquitoes that spread WNV are in the genus Culex. Culex mosquitoes are widespread in California and will feed on birds, other animals, and humans. Mosquitoes get the virus by feeding on an infected bird and may transmit the virus to humans the next time they bite. Culex mosquitoes tend to bite in the morning and evening and are not known to spread Zika, dengue, or chikungunya viruses.

How can you lower the risk of West Nile virus?

To lower your risk to mosquito bites and West Nile virus, the California Department of Public Health and the Centers for Disease Control and Prevention (CDC) recommend the following:

  • Avoid mosquito-infested areas at dawn and dusk.
  • Consider wearing long-sleeved shirts and long pants when you are outdoors. The mosquitoes that transmit WNV bite in the early morning and evening, so it’s important to wear proper clothing and repellent if outside during these times.

  • Use Environmental Protection Agency (EPA)-registered repellents containing DEET, picaridin, or oil of lemon eucalyptus. These are effective defenses against mosquitoes when used as labeled. Do not use permethrin products directly on your skin, and if you’re also using sunscreen, apply sunscreen first and insect repellent second.

  • Check your window screens for holes to make sure that mosquitoes cannot enter your home.

  • Dump stagnant water. Do not allow water to collect and stagnate in old tires, flowerpots, swimming pools, birdbaths, pet bowls, or other containers. These are prime breeding grounds for mosquitoes.

  • Clean and chlorinate swimming pools, and drain water from pool covers.

  • Stock garden ponds with goldfish or other mosquito-eating fish. These eat mosquito eggs, larvae (“wrigglers”), and pupae (“tumblers”).

  • Empty and wash birdbaths and wading pools weekly.

  • Cover rain barrels and empty weekly.

If you have questions about mosquitoes, call or text Clark at (800) WE-NEED-YOU (936-3339) or email Even though Clark does not offer mosquito services, we can answer your basic questions and put you in touch with your local mosquito and vector control agency for more information.

Until next time, the pest management professionals at Clark Pest Control thank you for helping to keep unwanted pests out of your home and yard.

Subscribe To Our Blog

Search our Blog