West Nile Virus and Insect Borne Diseases

WebMD Live Events Transcript

West Nile virus is making its way from coast to coast. And Lyme disease and Rocky Mountain spotted fever are still out there. We talked about insect-borne illnesses: precautions, insect control, symptoms, and more with our "diseases in the news" expert, Georges Benjamin, MD, and Virginia Caine, MD, on July 27, 2004.

The opinions expressed herein are the guests' alone and have not been reviewed by a WebMD physician. If you have questions about your health, you should consult your personal physician. This event is meant for informational purposes only.

MODERATOR:
Welcome, doctors. It is great to have two public health experts with such a depth of knowledge about infectious disease with us today. Let's start off with questions about West Nile disease.

MEMBER QUESTION:
West Nile was confirmed in our neighborhood this summer, so the local municipality is sending out the sprayer trucks. Are the chances of getting West Nile so great that we have to breathe this pesticide? What else is it killing besides the mosquitoes? What about my dogs who spend a lot of time outside?

CAINE:
Most of the mosquito trucks spray a biodegradable product so that the chemical agent usually dissolves within 30 minutes. But if you have allergies or certain respiratory disorders, we usually like to give a 24-hour notice, so you can make sure all your doors and windows are shut and can try not to be out in that air within the 24 hours after spraying in the outside environment.

BENJAMIN:
Also, many communities use a variety of mosquito-control efforts, so in addition to the spraying there are other methods. The most effective thing is getting rid of standing water.

CAINE:
Such as no abandoned tires.

BENJAMIN:
Secondly, there are larvacides. These are things you can put in water, so if you have a pool or fish pond they get rid of the baby mosquitoes. But getting rid of standing water is a very important thing people can do. You will be amazed where you can find standing water:

  • Wading pools
  • Pots and planters around the yard
  • If you have a swing that has an indentation in the swing, and that swing is not used very often, it can hold water after rainfall
  • Gutters that are backed up
  • Toys or tools that are left in the yard
CAINE:
We ask anybody who has a wading pool to change the water on a weekly basis, if they can't get rid of it on a daily basis. Birdbaths should be cleaned too, as well.

MEMBER QUESTION:
Are mosquitoes only a risk at dawn and dusk? Is that the only time they are out (do they sleep during the day)?

CAINE:
You're at the highest risk from mosquitoes from dusk to dawn. That's their time for feeding, so your chances are higher of getting bit, but mosquitoes can bite you any time of the day.

BENJAMIN:
Also, when West Nile first entered the U.S., the type of mosquito that was infected tended to be more active in the dusk and the dawn; however, in some parts of the country we're beginning to see mosquitoes that are infected that bite at any time. So the recommendation about dusk and dawn is still valid, but people, if they're going out camping or out picnicking or outdoors, should always protect themselves from mosquitoes.

CAINE:
People should think about using protective clothing and also using a propellant spray containing DEET. The DEET should not be sprayed on a person's skin, but on the clothing items.

BENJAMIN:
You should read the product insert very carefully and talk with your doctor about using DEET with young children. There are some cautions about using DEET with young children.

"In some parts of the country we're beginning to see mosquitoes that are infected that bite at any time. So the recommendation about dusk and dawn is still valid, but people should always protect themselves from mosquitoes."


MEMBER QUESTION:
What is the name of the virus that causes West Nile disease (etiological agent(s))? What is the incidence of West Nile virus found in the Washington metropolitan area? Has anyone or any institution cultured the agent?

CAINE:
The virus can be isolated from the blood of three-fourths of patients on the first day. I think it's primarily a serologic test.

BENJAMIN:
Yes, they can identify the virus, but that's not the important issue. The important issue is of the people who get infected, nearly 20% get West Nile fever. Of those who get ill, less than 1% gets the severe form of disease. The more we know about this disease the more we're discovering more people have been infected, but the good news is the vast majority of people don't get ill.

I'm not aware of reports in the Washington, DC, area this season. We certainly know it's in Washington, DC. The first case in the region was in Baltimore, Md., nearly three years ago. It has been detected in Maryland, the District of Columbia, and Virginia. It should be expected that the disease will return, maybe later this summer.

MEMBER QUESTION:
What are the symptoms of the West Nile virus?

CAINE:
Usually anywhere from one to six days after being bitten a patient can present with:


STAY INFORMED

Get the Latest health and medical information delivered direct to your inbox!