West Nile Virus Information

Information from the "Fight the Bite" brochure
Some interesting LOCAL information
Mosquito Control Using BTI

Fight the Bite

Why should you worry about West Nile virus?

• West Nile virus can make you and your family sick.
• West Nile virus is spread by mosquitoes.
• You get West Nile virus from a mosquito bite
• You can feel sick 3 – 15 days after a mosquito bites you.
• People who get sick may feel like they have the flu. They may have:
  • Fever
  • Headache
  • Body Aches
  • Rash
• Some people who get West Nile virus get very sick and die.
• Most people who have gotten really sick have been about 50 or older, but everyone needs to be aware of mosquitoes, and keep them away.

Call your doctor or clinic if you have questions.

What can you do?

• Avoid mosquito bites!
• Mosquitoes bite in the early morning and early evening hours.
• Two hours after the sun sets is when mosquitoes bite the most.
• If you go out at these times wear long pants and long sleeved shirts.
• Also, use insect repellent with DEET in it. Put the repellent on your skin that is not covered by clothes.
• The DEET in the insect repellent keeps mosquitoes from biting you. Follow the directions carefully.

Keep your home safe!

• Mosquitoes lay their eggs and grow in standing water.
• It only takes 7 days for a mosquito egg to hatch and become an adult mosquito.
• Get rid of standing water around your home.
• Empty water out of buckets, old tires, flower pots and toys.
• Change water every few days from pet bowls and bird baths.
• Keep good screens on your windows and doors.
• Screens will keep mosquitoes out.

Tell your friends and neighbors!

• West Nile virus is now found throughout California.
• Dead birds are a sign that West Nile virus is in your area.
• Birds like crows, ravens, and jays get very sick and can die from West Nile virus.
• You do not get West Nile virus from touching a dead bird.
• To monitor the spread of the virus, the State is tracking dead birds.   To report a dead bird, go to www.westnile.ca.gov or call toll-free 1-877-WNV-BIRD   or 1-877-968-2473.

For more facts

• California Department of Health Services West Nile Website
• Centers for Disease Control and Prevention Website
• Placer County West Nile Virus Website
• Placer County Mosquito Abatement District
• Nevada County West Nile Virus Website

Some Interesting LOCAL information

This year we have not yet detected any WNV activity in the Donner Summit area.  We have had one bird test positive for West Nile virus (WNV) in Placer County this year, and that bird was collected from Lincoln. 

In 2004 however, WNV was widespread throughout CA, including some alpine areas.  One of the first birds to test positive for WNV in our county last year was a Northern Goshawk collected from Emigrant Gap, and there were several WNV-positive birds collected from the communities around Lake Tahoe. 

Twenty-nine mosquito species occur in Placer County.  Not all of these mosquitoes are nuisances (some do not even bite people), and not all of these mosquitoes are able to transmit diseases.  The mosquitoes that play the greatest role in WNV transmission are the Culex mosquitoes.  Culex mosquitoes are found anywhere where people live, including Serene Lakes.  Culiseta mosquitoes are another common mosquito in the High Sierras, and are also very effective vectors of West Nile virus.  Both the Culex and Culiseta mosquitoes develop in standing water found in containers in backyards.  Both are stealthy in their feeding habits, and we often only notice their bites many hours later.  These are the mosquitoes that you typically hear buzzing in your ear when you lay down to sleep at night.  These species generally do not fly far from where they hatched, and you can do a lot to reduce your family’s risk – and your neighbors’ risk - of WNV by eliminating standing water in your yard.  By inspecting your yard once a week, and dumping out any standing water (buckets, wheelbarrow, clogged roof gutters, toys, tarps, etc.), you can prevent mosquitoes from breeding in your backyard and help to protect your family, your neighbors, and your pets from mosquito bites and West Nile virus.  

The mosquitoes that you are probably most familiar with in your area are the large, very aggressive nuisance mosquitoes that bite during the day.  These are Ochlerotatus and Aedes mosquitoes.  Aedes and Ochlerotatus mosquitoes develop in the pools of snowmelt water and in the low, wet areas of meadows in the springtime, and the adults can persist through July.  These species have not been identified as vectors of West Nile virus.

Although an estimated 80% of people who are infected with West Nile virus will not become ill, 20% will experience moderate to severe symptoms that may persist for weeks or months, and some people may never recover completely.  People over 50 years of age or with compromised immune systems are much more likely to have serious symptoms. 

We recommend that all residents can help protect themselves from mosquito-borne illness by following the “Four D’s:”

• DRAIN standing water!  Mosquitoes can develop into biting adults in as little as 4 days in the summer.  Inspect your yard once a week, and dump any standing water that you find.  Store buckets, flower pots, wheelbarrows, and other containers upside-down to prevent them from collecting water from sprinklers.  Change the water in children’s wading pools, birdbaths, and pets’ water dishes 1-2 times per week. 
• Put mosquito fish in your stock tanks and ornamental ponds.  Call or visit the Placer Mosquito Abatement District mosquito for FREE mosquito fish. 
• DUSK and DAWN are when mosquitoes are most active.  When possible, avoid being outside at these times. 
• DRESS in long-sleeved shirts and long pants if you must be outside when mosquitoes are biting. 
• DEET: Use an insect repellent that contains DEET.  Always read and follow the label directions.  The Centers for Disease Control (CDC) recommends that no more than 10% DEET be used on children, and no more than 30% for adults.  Several companies now sell DEET wipes that are easier to use and less messy than traditional sprays.  

You can check the State’s West Nile virus website (www.westnile.ca.gov) and the Placer County WNV website (http://www.placer.ca.gov/hhs/hhs-sub/com-diseases/west-nile-virus.htm) for the most recent information about WNV in our area. 

I’d be happy to answer any questions that you have regarding mosquito abatement or West Nile virus.  Please feel free to call or email me if you would like more information. 

Sincerely,

Jamie Scott

Jamesina J. Scott, Ph.D.
Vector Ecologist
Placer Mosquito Abatement District
150 Waverly Drive
Lincoln, CA 95648

jjscott@placermosquito.org

Tel: (916) 435-2140
FAX: (916) 435-8171

Mosquito Control using BTI

BTI is a naturally occuring soil bacterium that can effectively kill mosquito larvae present in water. BTI is very specific for mosquitos and black flies. When eaten by the mosquito larvae the spores release toxins into the mosquito's gut, causing the larvae to stop eating and die.

BTI is available in liquid, briquette, and granular form. A common BTI product is a doughnut shaped block called Mosquito Dunks. They dissolve slowly in water and are effective for up to 30 days. A faster form of the product comes in granular form. It is effective for up to 2 weeks, and starts working within 24 hours of application.

SLPOA has purchased a supply of the granules for homeowners to use on puddles and swampy areas around their property, and Robin Burke has packaged the granules for distribution. If you would like more information or want to get some to treat your lot, contact Robin Burke (robinjoy@earthlink.net) or call her at 426-9519.

The Placer County Mosquito Ababement District encourages the use of these products in backyard mosquito sources that cannot be eliminated or drained, such as ornamental ponds and out-of-service (“green”) swimming pools and spas. These “backyard sources” are the most common source for the Culex mosquito species that transmit West Nile virus; because the Culex mosquitoes typically do not fly far, residents can literally reduce the risk of contracting this disease by draining or treating mosquito habitats in their own yards. However, I would discourage residents and the Serene Lakes Property Owners Association (SLPOA) from using these products in the public and natural areas for the following reasons:

• The absence of a coordinated application program will likely lead to over- or under-applications of mosquito control products. Mosquito sources need to be inspected to determine if mosquito larvae are present, and only then should mosquito control products be applied.
• My greatest concern however, is that the under-application of these products by non-certified personnel will promote resistance in the mosquito populations, and will reduce the effectiveness of B.t.i., and limit the mosquito control options available in the future.