The buzz and the bite are back

West Nile Virus threat looms large after heavy rains and warm temperatures



Mosquito season is upon us - already. It's earlier this year because of heavy rains and warm temperatures, which means that the possibility of West Nile Virus is also present.

Before 1999 in this country, mosquitoes were merely an annoying and noisy pest, as anyone who loves the outdoors will attest. No rhyme is intended, but there is reason for greater concern about the mosquito these days, as anyone from the Department of Health Services in SLO County will confirm.

West Nile Virus (WNV) is a mosquito-borne virus found in Asia, Eastern Europe, Africa, and the Middle East. It was first discovered in this country in 1999 in New York City.

In 2003, a total of 45 states detected WNV activity and more than 9,300 cases, including nearly 250 deaths. In 2004, there were 822 reported cases in California - one in SLO County. Twenty-five deaths were reported in the state, all in Southern California.

The majority of people infected with the virus will experience either no symptoms or a mild to moderate illness including fever, headache, nausea, body aches, skin rash, or swollen lymph nodes. Severe cases may include viral meningitis or encephalitis, which affects the brain and may require hospitalization. Those who survive the disease can face speech and swallowing difficulties and problems with memory and balance.

"Most people won't know they have the disease, but for the elderly and very young children it can be serious, and in the case of elderly people there is a certain percentage who do die," said Steve Carnes of SLO county Environmental Health Services.

Alarming as West Nile Virus appears, chances of getting the disease are slim, due to mostly awareness and a rigid government monitoring and control.

Still, common sense should prevail.

"We've had a lot more rain than the previous three to four years, and once the rain stops and water starts to stagnate and stop flowing, that's going to create an ideal breeding ground for mosquitoes," said Carnes.

All of which means removing any source of pooled water often found in tires, cans, plant containers, fountains, clogged rain gutters, and of course nearby creeks, all places where mosquitoes lay eggs.

A single small bucket of water can produce thousands of mosquitoes every week, since the insect can mature from egg to adult in seven to 15 days.

Only certain species of mosquitoes carry WNV, and few are actually infected. They get the disease by feeding on a bird with the virus in its blood.

Health officials can't exterminate mosquitoes, but they can prevent them from passing down the disease.

"The primary emphasis in our treatment program is to target and look for the counts and adult trapping that we do to trigger when we start treating to try to prevent the next generation of the mosquitoes that do have the capability of transmitting the disease," said Carnes.

SLO County hasn't initiated a specific vector control program like other areas, but relies on the Environmental Health Department through its mosquito-abatement program.

Getting rid of standing water is the first part of the program; the second is to not get bit.

Again, common sense and awareness is the key here. It's better not to go out during dawn or dusk when mosquitoes are actively biting. Repair screens, windows, and doors to keep mosquitoes out of the house. If you are outside, wear protective clothing and use a repellant with DEET.

And, while you're out there, look for dead birds. That's a fairly certain sign that mosquitoes infected with WNV may be in your area. Such mosquitoes bite the birds, and the birds die. Infection has been reported in more than 200 bird species, but look particularly for crows, ravens, jays, and magpies.

If you find any dead birds, call the DHS at 1-877-WNV-bird.

"Dead birds is where people come into play as far as the reporting," said Carnes. "Mosquitoes bite or sting birds who get the virus and die. Then we look for sources of mosquitoes in conjunction with that."

Dogs and cats generally don't get ill when bitten. Horses can, but there is a vaccine.

As of yet, there is no vaccine for humans. Carnes says the best you can do is to be smart and protect yourself. ³


Managing Editor King Harris can be reached at

Add a comment