West Nile Virus

(Are you scared yet?)

West Nile Virus (WNV) is a mosquito-borne virus that infects humans. It can cause sickness and fatalities, and it is being spread rapidly across the US by birds (it is primarily a bird disease) that act as an intermediate host. There is a lot of panic around the spread of the virus. This is caused by inaccurate and shoddy media reporting and the media's natural inclination to garner more market share with shocking stories, along with the corporate interests of pesticide companies to sell more product.

What Are The Relative Chances of Dying From WNV?

If WNV were to spread across the US and become endemic in every state, we would see a death toll of roughly 300-500 people per year, and a slightly larger number would become seriously ill. This sounds scary - a mosquito bites you, and soon you are dead. But what are your chances of dying from other causes?

(All of these are in the US unless noted)

91,871 died from influenza and pneumonia in 2000.
7,700 over age 65 (not to mention younger folks) died as a result of falls in 1995.
About 48,000 die each year from highway accidents.
18,000 deaths each year are attributed to the lack of health care insurance. <USA Today 5/22/02>
7,000 deaths per year are caused by administering the wrong drug in hospitals.
80,000 die from infections they acquired (nosocomial infections) during a hospital stay.
106,000 deaths are caused by people getting the right drugs but the side effects kill them.
About 150 people die each year worldwide from coconuts falling on them.
About 90 people each year are killed by lightning strikes.

You are almost equally likely to die from WNV as from being struck by lightning. You are 1000 times as likely to die from the flu or pneumonia or going to the hospital to presumably get healthy or even driving to the hospital. And if you don't have health insurance - and 40 million Americans don't - you have at least a hundredfold greater chance of dying because you can't even afford to go to the hospital. The average age of people dying from WNV in the US so far is 78, so this is a disease, like pneumonia and the flu, that kills mostly the weak and infirm.

It is absurd to get much more upset about dying from WNV than about a neighbor planting a coconut tree on your property line.

Well over 90% of people who are infected with WNV show no symptoms at all and never even realize they have been infected. A very small percentage get mild flu-like symptoms. Only a tiny fraction of a percent get seriously ill, and of those, only a few die. Some experts think WNV is very much like other mosquito-borne encephalitis diseases (that we don't even hear about) that already exist and are endemic in the US and kill or sicken only a few hundred people per year.

What is the REAL danger of WNV?

The real danger posed by WNV is overreaction by governments and the much greater susceptibility and mortality among animals, notably birds of the corvid group (crows, jays) and horses. The only way to reduce the spread of WNV and decrease the chances of infection is to remove the "transmission vector", that is, the mosquitoes. The methods for this, in order of effectiveness, are

Prevent mosquitos from breeding (remove habitat or use other suppressive measures)
Kill the mosquito larvae
Prevent mosquitos from landing on you (wear long sleeves, get screens, don't go outside at dawn and dusk)
Kill the adult mosquitos

The first line of response, then, is to remove habitat - dry up puddles, dump out sanding water in pots, barrels, tires, and bird baths. After this is done, if there still is a problem, the mosquito larvae may be attacked with passive measures such as oils or active pesticides such as Bti. Bti, a bacillus, is not completely harmless and its long-term effects on human health and the environment are not completely understood (go to our home page for more information on Bt). Then, exposure to adult mosquitos should be reduced by taking prudent measures (notice mosquito repellent was not mentioned - DEET, the active ingredient, has been associated with neurological damage in humans) .

Contrary to any reasoned response, when WNV appears, some state and local governments call on pesticide companies (or even the Air Force, which has equipment for massive aerial spraying) to conduct huge spraying campaigns to kill mosquitos. But this is an ineffective approach. Spraying only kills 10% of the adult mosquitos and does little to stop breeding.

The result of the spraying campaigns, which use chemical pesticides such as permethrin, malathion, and others, is to cause a disproportionate sickness and eventual death rate in the exposed human population, not to mention devastation in the environment. The chemicals used for mosquito control are universally questionable as to their safety. We can almost certainly expect a much higher death rate from being exposed to these chemicals than from WNV.

What Can You Do?

The Washington State Department of Health has provided an integrated pest management plan (IPM) template, which specifies, to some extent, that local governments should not spray adulticides except as a last resort. The emphasis should be on preventing breeding of mosquitos. Any local government may decide to pursue any plan, including immediate and repeated pesticide spraying, but they will not be covered under the state's liability protection if they do so. To be covered, they must submit and follow an approved IPM program. The city of Seattle has a more exacting IPM program , as well as King County. However, the city of Everett has decided to spray adulticides.

We need to make sure our government understands the relative risks of WNV versus spraying. We need to have them spend time educating the public that there is no reason to panic about WNV. If our government wants to panic they should be panicking about lack of health insurance, not enough drug treatment centers, and slippery bathroom floors. Write letters to the editors of local papers stating the points above. Contact your local officials. Tell them you don't want any spraying - it's a lot safer to take your chances with WNV than with malathion.

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