A cool breeze whispers across your yard as you sit comfortably in a lawn chair watching the waning sun. The fantastic reds, oranges, and yellows light up the evening sky and the sibilant rustling of the leaves on the trees couples with melodic burbling of a nearby brook. Nothing could improve on this dulcet moment, but something could definitely intrude—such as the cacophonous buzzing of a mosquito exploring the sanctum of your inner ear.

In recent years, that zinging buzz has graduated from a mild annoyance to a very real health concern. While the summer and fall seasons are characterized by picnics, baseball, and water sports, it’s also the season of mosquitoes; and since 1999, mosquito season has also become synonymous with West Nile Virus (WNV). The mosquito’s buzzing intrusion into your otherwise perfect summer day need not strike fear into your heart. With a few simple precautions, you can prevent WNV from affecting yourself, your family, and your community.

A Longer History Than You Might Think

While WNV is a relatively new disease in the United States, in the worldwide community it has been around for quite a while. Since 1937—when the first reported human case of WNV was discovered in a woman from the West Nile District of Uganda—WNV has been spreading throughout the world. Since the first human case, WNV has spread across Africa, Eastern Europe, West Asia, and the Middle East. Eventually, the disease found its way to the Eastern United States. No concrete evidence points to exactly when WNV arrived on American shores, but scientists from the U.S. Center for Disease Control (CDC) agree that it first appeared in the early summer of 1999.

What Is West Nile Virus?

If you want to get technical, WNV belongs to the Flaviviridae family. There are approximately 70 different known types of Flaviviruses, 13 of which cause diseases in humans—you might recognize some of WNV’s cousins, which include dengue, yellow fever, and encephalitis. Flaviviruses, as you might expect, are typically transmitted through mosquitoes and ticks and hosted largely in birds. WNV pertains to the Japanese Encephalitis serocomplex, and is closely related to St. Louis Encephalitis. Tracing the roots of the first cases of WNV reported in New York City indicates that the virus probably came from Israel or the Middle East.

If we took all that scientific jargon and boiled it down into simple terms, what you really need to know is this: WNV is a virus with over 70 variations that can infect humans, birds, horses, and other mammals. Its life cycle relies on birds as vertebrae hosts and mosquitoes as vectors (organisms that transmit a pathogen). Transmission of the virus happens when mosquitoes bite infected birds and are infected themselves. The virus is stored in the mosquito’s salivary glands and is spread to new hosts when the mosquito stops for a meal.

Unfortunately, WNV seems to have established itself as a seasonal epidemic in North America. With flare ups happening every summer and continuing through the fall, and with the serious potential of the disease, WNV is not something to dismiss lightly.

West Nile Virus Infections

Very few people are actually infected with WNV; relatively few mosquitoes actually carry the virus. In fact, according to the CDC, less than one percent of people bitten by mosquitoes will develop any symptoms of the disease. People who are outdoors more are most at risk of being infected, while people over the age of 50 are more at risk for developing symptoms of WNV. Very few children and healthy adults have to worry about WNV. Transmission through medical procedures—such as blood transfusions or transplants—or through pregnancy and nursing is very unlikely.

Symptoms

If you do get infected with WNV, the odds are still in your favor. Approximately 80 percent of infected people will not develop any symptoms, reports the CDC. The vast majority of people who do develop symptoms will only experience mild symptoms, and only about one out of every 150 people will develop serious symptoms. Most symptoms of WNV will appear within 3-14 days of infection.

West Nile Fever. Of the few people that develop any symptoms from WNV, most will experience mild symptoms like fever, headache, body ache, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach, or back. Development of such symptoms has been called West Nile Fever. West Nile Fever will gradually improve on its own, generally over a few days (though some cases have reported the symptoms lasting up to several weeks), and does not require medical attention.

West Nile Encephalitis, Meningitis, and Poliomyelitis. Serious symptoms resulting from WNV infection are very rare—less than one percent of people infected by the virus will develop them—and remember, less than one percent of people bitten by mosquitoes will be infected by WNV. Those that do develop serious symptoms are at risk of neuroinvasive diseases like encephalitis, meningitis, or poliomyletis. Neuroinvasive diseases affect a person’s nervous system, causing swelling in the brain, spinal cord, or the membrane that surrounds the brain or spinal cord. Symptoms include severe headaches, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. If you experience any of the above, seek medical help immediately.

Treatment

Most cases of WNV can be dealt with by using the same treatments you would use for mild flu symptoms. If you actually do develop any symptoms, you can treat them with medication for headaches, body aches, or fevers.

Serious symptoms require medical attention and may result in hospitalization. But again, don’t jump to conclusions; only one out of every five people infected by the virus will actually develop any symptoms at all.

Is There a Vaccine?

To date, no human vaccine for WNV has been developed, although the outlook is promising. A vaccine has been developed and licensed for horses, but its effectiveness has not been fully evaluated and has not been tested on humans. Not only is its effectiveness in humans completely unknown, but it could be potentially harmful if ingested. Veterinary vaccines are not manufactured to the same standards as those used for human vaccines. They also do not undergo the rigorous testing required for human vaccines. As such, taking veterinarian vaccines or medications could be extremely harmful to humans.

Preventing West Nile Virus

As with any disease, the best way to treat WNV is to not contract it; and the best way to avoid contracting WNV is to not get bit by mosquitoes. It sounds next to impossible, but preventing mosquito bites is not only plausible, but fairly simple.

Personal Prevention

A few simple steps can prevent mosquito bites—and thus WNV infection.

Always use an insect repellent. There are many different types of repellents on the market today, but the most effective are those that contain DEET (N, N-dyethyl-meta-toluamide). According to a study reported in the New England Journal of Medicine, products that do not contain DEET do not offer as much protection or last as long as those that do. One product in the study that contained a soybean-oil base provided a similar benefit of those with a low concentration of DEET. Nonetheless, the study reports that among those products tested on humans and mosquitoes, only those containing DEET offered long-lasting protection.

The study also provided general guidelines for how long a DEET-based product will prevent mosquito bites. According to the study, a product containing

• 23.8% DEET provides an average of 5 hours of protection
• 20% DEET provides almost 4 hours of protection
• 6.65% DEET provides almost 2 hours of protection
• 4.75% DEET and 2% soybean oil provides roughly 1.5 hours of protection

(Fradin MS, Day JF. Comparative efficacy of insect repellents against mosquito bites. N Engl J Med. 2002;347(1):13-8.)

You may have heard that DEET repellents aren’t safe. This is one myth you can discredit completely. Because DEET is so widely used, extensive testing on its safety has been conducted. In its R.E.D. facts sheet report on DEET, the EPA stated that “the normal use of DEET does not present a health concern to the general U.S. population.” DEET products are also safe for pregnant and breast-feeding women.

That’s not to say that DEET repellents can be used without caution. In some rare cases, DEET has caused allergic reactions and seizures. Should you develop either, cease using it and seek medical help—make sure to take the product with you. Additionally, DEET is an eye and mouth irritant. Rather than spraying it directly onto your face, spray some on your hands and then apply it to your face. Instead of spraying the repellant on children, spray it on your hands and then apply it on them. Avoid putting the repellant on a child’s hands as they have a tendency to rub their eyes or put fingers in their mouths. Don’t apply DEET repellants under clothing or in enclosed areas.

If you are outside longer than expected, sweat profusely, or get wet, reapply the repellent.

Wear Long Sleeves, Long Pants, and Socks. OK, it’s summer; you’re supposed to be wearing shorts, t-shirts, and sandals. Using an insect repellant on exposed skin can protect exposed areas, but whenever possible—and especially during peak mosquito hours—cover up with clothes. Additionally, spray your clothes with the repellent as mosquitoes can bite through thinner material.

Avoid Peak Mosquito Hours. While a few species of mosquitoes are active throughout the entire day, most are biting during dusk and dawn hours. Take extra care, or go indoors, during these times.

Don’t Rely on Mosquito Control Programs. Many communities utilize a mosquito control program, but that doesn’t mean you can relax on your preventative efforts. Even if your community has such a program, you should still do your part in preventing mosquito bites.

Home Prevention

Now that you know how to protect yourself, what about protecting your home and family?

Invest in Good Screens. Making sure that your doors and windows are covered with screens that are in good condition is an important step in preventing mosquito bites.

Remove Mosquito Breeding Sites. Mosquitoes need standing water in order to propagate. Remove standing water—or replace it on a weekly basis—from flower pots, buckets, barrels, and any other objects that can hold water (such as swing seats, pet dishes, bird baths, and clogged rain gutters). With no places to lay their eggs around your home, mosquitoes will have to go elsewhere.

Protect Your Children. Make sure that your children are wearing insect repellant and that infant carriers are covered by mosquito netting when outdoors.

Community Prevention

Creating a mosquito-free oasis in the middle of a mosquito-epidemic will do little good—mosquitoes aren’t afraid of crossing over fences. You’ll need to help your community prevent WNV breakouts as well.

Mosquito Control Programs. You can find out from local health authorities if your community has a mosquito control program. If there isn’t one, work with your local government to develop a program. The American Mosquito Control Association (www.mosquito.org) has great advice on initiating and maintaining a mosquito control program.

Neighborhood Cleanups. Removing mosquito breeding sites from around your home is an important step. Take that step a bit farther and remove mosquito breeding sites from your community. Civic and youth organizations, or even neighborhood groups can organize neighborhood cleanups to remove containers from vacant lots and parks and encourage homeowners to do the same for their own property.

Report Dead Birds. Dead birds may be a sign of WNV in your area. According to the CDC, 284 species of wild and captive birds have been infected by the virus. This doesn’t mean that every dead bird you see died from WNV, but reporting dead birds to local authorities may prevent an outbreak in your community. Remember, never handle a bird carcass with your bare hands. Contact local authorities for instructions on reporting and disposing of the dead body.

It’s All about Prevention

When it comes to West Nile Virus, it’s all about prevention. All indications tend toward West Nile Virus being here for the long haul, but there’s plenty you can do to prevent personal infection or an outbreak in your area. As an added benefit, these same steps can help prevent the many other mosquito-borne diseases. Just like the proverbial “ounce of prevention,” a few minor steps now can prevent bigger problems later.