What Is West Nile Virus?
West Nile virus is a mosquito-borne virus that can infect humans, birds, horses and other mammals. In most humans, West Nile virus infection causes a mild or moderate, short-lived flu-like illness, or causes no symptoms at all.However in some cases, particularly among persons 50 years of age and older, it can cause serious neurological diseases such as encephalitis, meningitis, or paralysis. West Nile virus first appeared in North America in New York City in 1999. Since then, the virus has spread across the continental United States.Visit CDC – West Nile Virus for more information on West Nile virus nationally.
What Are The Symptoms Of West Nile Virus?
Most people who are infected with West Nile virus either have no symptoms (80%) or experience a mild or moderate illness with symptoms such as fever, headache, fatigue, or body aches before fully recovering. It is estimated that 20% of people who become infected with WNV will develop West Nile Fever. Of these, 1/150 persons may develop the more serious neuroinvasive West Nile.Some persons may also develop a rash or swollen lymph glands. In some individuals, particularly persons 50 years of age and older, West Nile virus can cause serious disease that affects the brain and spinal tissue. Severe illness may include encephalitis (inflammation of the brain), meningitis (inflammation of the membrane around the brain and spinal cord), or acute flaccid paralysis (a polio-like syndrome in which muscles become very weak or paralyzed). Symptoms of more severe disease may include headache, high fever, stiff neck, nausea and vomiting, confusion, coma, tremors, convulsions, muscle weakness and/or paralysis. At its most serious, West Nile virus can cause permanent neurological damage and death. Among those people who need to be hospitalized for West Nile virus, 10-15% die of their illness. People who do develop symptoms normally become ill 3-15 days following the bite of an infected mosquito.
How Is West Nile Virus Spread?
- Infected Mosquitoes. Most often, WNV is spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds. Infected mosquitoes can then spread WNV to humans and other animals when they bite.
- Transfusions, Transplants, and Mother-to-Child. In a very small number of cases, WNV also has been spread through blood transfusions, organ transplants, breastfeeding and even during pregnancy from mother to baby.
- Not through touching. WNV is not spread through casual contact such as touching or kissing a person with the virus.
How Is West Nile Virus Prevented?
Prevent Mosquito Bites
A single mosquito bite can make you sick. Why take a chance? Use repellent on yourself, your friends and your family.Many people who are bitten by an infected mosquito won’t get sick—others aren’t as lucky. Since 1999, more than 30,000 people in the United States have been reported as getting sick with West Nile virus. Occasionally, an infected person may develop more severe disease such as “West Nile encephalitis,” “West Nile meningitis” or “West Nile meningoencephalitis.”
Control what you can.
Improve your odds of avoiding mosquito spread viruses by using a repellent on exposed skin and clothes while outdoors.Insect Repellent: It keeps you from being what’s for dinner.
CDC recommends Think of repellent as you would an important article of clothing, and increase your chances of avoiding aches and fatigue that come with West Nile fever, dengue fever, or any number of other mosquito borne diseases.What repellent should I use? CDC – Recommended Repellents for West Nile Virus . The most important step is to pick one and use it. DEET, picaridin, IR3535 and the plant-based oil of lemon eucalyptus are all repellents recommended by CDC. All contain an EPA-registered active ingredient and have been studied to make sure they are effective and safe.When should you wear repellent? Mosquitoes can bite anytime. Most of the mosquitoes that carry West Nile virus bite from around sundown (dusk) to around sun-up (dawn). Keep repellant in an easily accessible place. Put a bottle in the car, by the door, in a purse or backpack.Prevention is the best defense against West Nile Virus. Arlington residents are reminded to enjoy the outdoors, and remember the Four D’s:
- Dusk and dawn are the times of day you should try to stay indoors. This is when infected mosquitoes are most active.
- Dress in long sleeves and pants when you’re outside. For extra protection, you may want to spray thin clothing with repellent.
- DEET is an ingredient to look for in your insect repellent. Follow label instructions, and always wear repellent when outdoors.
- Drain standing water in your yard and neighborhood where mosquitoes can breed. This includes old tires, flowerpots, clogged rain gutters, etc. Mosquitoes may develop in any water stagnant for more than three or four days.
How is West Nile Virus treated?
There is no specific treatment for West Nile virus. Most people who become infected will get better on their own. In more severe cases, intensive supportive therapy is indicated, i.e., hospitalization, intravenous (IV) fluids and nutrition, airway management, ventilator support if needed, prevention of secondary infections and proper nursing care.
Who is most at risk for getting severe West Nile virus disease from being bitten by an infected mosquito?
- People over 50 at higher risk to get severe illness. People over the age of 50 are more likely to develop serious symptoms of WNV if they do get sick and should take special care to avoid mosquito bites.
- Being outside means you’re at risk. The more time you’re outdoors, the more time you could be bitten by an infected mosquito. Pay attention to avoiding mosquito bites if you spend a lot of time outside, either working or playing.
- Immunocompromised persons, such as persons who have received organ transplants.
How long does it take to get sick if bitten by an infected mosquito?
Most people who are infected with West Nile virus have no symptoms or experience only mild illness. If illness does occur, symptoms generally appear between 3 to 15 days of being bitten by an infected mosquito.
Can you get West Nile virus directly from birds?
There is no evidence that a person can get the virus from handling live or dead infected birds. However, persons should avoid bare-handed contact when handling any dead animals and use gloves or double plastic bags to place the carcass in a garbage can.
What is being done to protect residents against West Nile Virus?
The City of Arlington relies upon surveillance, both by residents and City crews, to identify and eliminate any standing water which could serve as a breeding place for mosquitoes and larvae. Typically larvae will thrive in still, shallow water less than 15 inches deep. Bird baths, pet bowls, wading pools, tire swings or any similar receptacle with standing water can serve as a breeding place for mosquitoes.COA utilizes progressive methods of protection which include public education, larvacide, and adulticide.
Would the City of Arlington ever spray for mosquitoes?
Spraying or adulticide isn’t the first line of defense against mosquitoes in Arlington, because for a number of years now, health authorities have concurred it is a less effective means of protection against mosquito-borne illness. However, if the problem does progress and there is a need for mitigation beyond surveillance and larvacide, the City of Arlington is prepared to move ahead with a spraying plan.In accordance with the Centers for Disease Control’s guidelines, which specify mosquito spraying is most effective when it is targeted and strategic in nature, the City may consider spraying in an area which meets the following criteria:
- A cluster of human West Nile Virus cases and,
- Positive West Nile Virus mosquito sampling in a targeted area
- Concurrent larvacide treatment
Will the public be notified in advance about spraying activities?
*** Advance notice will be provided if a decision is made to spray. The spraying location, schedule and time will be provided to the news media and posted on the city’s website.
What health risks are posed to people and pets from pesticides for adult mosquitoes?
Effect on human health is one of the primary factors considered in regulation of pesticides. Pesticides that can be used for mosquito control have been judged by the EPA not to pose an unreasonable risk to human health. People who are concerned about exposure to a pesticide, such as those with chemical sensitivity or breathing conditions such as asthma can reduce their potential for exposure by staying indoors during the application period (typically nighttime).A recently published study, CDC – MMWR – Surveillance for Acute Insecticide-Related Illness Associated with Mosquito-Control Efforts examined illnesses in nine states associated with exposure to pesticides used to control mosquito populations from 1999-2002. This study found that “application of certain insecticides poses a low risk for acute, temporary health effects among person in areas that were sprayed and among workers handling and applying insecticides.” For more information on pesticides and health, consult the U.S. EPA – Pesticides, which oversees the registration of these chemicals. The National Pesticide Information Center (NPIC) (NPIC) can also provide information through a toll-free number, 1-800-858-7378 or online.
- Remember the 4 Ds on West Nile Virus – English
- Remember the 4 Ds on West Nile Virus – Espanol
- Remember the 4 Ds on West Nile Virus – Vietnamese
- Texas Department of State Health Services – West Nile Virus
- West Nile Virus – What You Need to Know
- West Nile Virus – Frequently Asked Questions
- Useful Links (Health)