West Nile Virus: Here's the Scoop

The recent news coverage of the mosquito borne West Nile Virus has many people concerned, and rightly so. Here in California, we're awaiting the impending arrival of the virus and since greenfeet.com is located in the heart of the agricultural area (rice fields are major mosquito breeding grounds) we decided a little research needed to be done. So, here's what we found:

What is the West Nile Virus?

West Nile Virus was first isolated from a woman in the West Nile District of Uganda in 1937. West Nile Virus is a mosquito borne flavivirus that has been found in Eastern Europe, parts of Asia, Africa and the Middle East. It was first detected in the U.S. in 1999 in New York City. It is closely related to the St. Louis encephalitis virus currently found in the U.S.

The West Nile Virus is hosted by birds. Mosquitoes are the vehicle by which it is transmitted. Only certain species of mosquitoes carry the virus and very few are actually infected. A mosquito first becomes infected by feeding on a bird with the virus in its blood (black crows, jays, ravens and magpies are just a few of the 70 species in which the virus has appeared). The virus is then transmitted to its new human or animal host from the mosquito's saliva when it bites.

Humans are accidental hosts for the West Nile Virus (as are horses). Human to human transmission does not occur and the virus spreads most frequently during prime mosquito season; from May to October.

What are the symptoms of West Nile Virus?

Most people with the virus experience no symptoms at all. Of those who become sick, symptoms can include fever, chill, nausea, headache, body aches, mild skin rash or swollen lymph nodes. In a few cases, the illness will progress to encephalitis (inflammation of the brain). The incubation period between the time of the bite and onset of symptoms ranges from 5-15 days. Estimations are that 1 in 150 people who become infected will require hospitalization. Of the 66 confirmed cases in the U.S. in 2001, nine (14%) died. The elderly, those with compromised immune systems and the very young are most at risk. There is no cure or specific treatment for infection of the West Nile Virus but supportive care is important. While there is no vaccine for humans, there is one available for horses.

What can we all do to prevent it?

Mosquito control is the best defense. Here are a few suggestions to help control the mosquitoes in your area. Some may seem like common sense - but they may be suggestions you've overlooked.

• Avoid outdoor activity during dawn and dusk when mosquitoes are the most active. This is very important for the very young and the elderly.
• Get in the habit of using mosquito repellent. We recommend natural repellents - there are some out there that are effective and are safe for use by all ages. Be sure to spray all exposed areas of skin including head and back of the neck. If you must use DEET, please don't spray it directly on your skin. It's been shown that after application to the skin, 56% of the DEET applied was absorbed into the skin and can remain in the body for up to two days. Wear long pants and sleeves, spray only on clothing and never use DEET on small children (there are cases where children have died from the use of DEET).
• Check to make sure that windows and doors have tight fitting screens. If they have tears or holes, repair or replace.
• Inspect weather stripping and caulking around windows, door jambs and floor moldings. Mosquitoes are experts into entering a home in the most inconspicuous ways.
• Install a bat house. A single, small American brown bat can gobble up to600 mosquitoes an hour - not bad pest control.
• Teach the kids to close the doors and sliders behind them. This, of course, is a feat in itself.
• Check for areas of standing water. Inspect under the house, gutters (clean and repair if necessary), old tires, holes in the yard, bird baths, wheelbarrows, etc. Standing water is a mosquito's paradise.
• For standing water such as ponds and birdbaths, use either mosquito dunks or mosquito fish. Mosquito Dunks are doughnut shaped pellets that contain millions of beneficial bacteria that dine on mosquito larvae. They are not to be used in places where humans or animals drink. Mosquito fish can usually be obtained for free from your local Mosquito control District. If you're unsure if you have one, call your local city or county offices and inquire. If you find standing water on public property, notify the city or county maintenance department and they will take measures to prevent mosquito infestation.
• Eat garlic. Not only is garlic good for your digestion, but apparently it keeps mosquitoes at bay. According to lore, mosquitoes are not fond of the garlic odor that oozes from your pores and are less likely to bite. We hear the same goes for Vampires.
• Plant basil. Mosquitoes are not fond of the pungent odor and are less likely to enter your home. Consider a plant or two on a sunny windowsill. You'll keep the bugs away as well as having the makings for fresh pesto anytime of the year.

It's important to note that there are many species of mosquitoes and they all respond differently to different methods of prevention. So, try and see what works for your home. Share with your neighbors. Together, using natural and predatory control, we can keep the mosquito population in check and diminish the threat of exposure to illnesses such as the West Nile Virus. Do you have a method that works for you? Email us and let us know!

greenfeet would like to thank the California Department of Health Services and the Center for Disease Control for providing information for this article.