Search


 

 

Mosquito Control Division

West Nile Virus Important Facts

What is West Nile Virus?

West Nile Virus (WNV) is a mosquito-borne disease that can cause encephalitis, or a brain infection. Mosquitoes acquire the virus from birds and pass it on to other birds, animals and people. In 1999, WNV first appeared in New York . Mosquitoes spread this virus after they feed on infected birds and then bite people, other birds and animals. West Nile encephalitis is caused by West Nile virus, a flavivirus previously only found in Africa , Eastern Europe , and West Asia . West Nile virus is closely related to St. Louis encephalitis virus ( SLE ), which is found in the United States .

How does WNVspread?

Mosquitoes can become infected with WNVby feeding on birds that have the virus in their bloodstream. Once a mosquito is infected with the virus it can transmit the virus to humans, birds, horses or other mammals through a bite.

Who is most at risk?

People over 50 years of age have the highest risk of developing a severe illness because as we age, our bodies have a harder time fighting off disease. People with compromised or undeveloped immune systems are also at increased risk, however, anyone can get the virus.

What are the symptoms of WNV infection?

Most people bitten by infected mosquitoes do not develop any symptoms. However when symptoms of infection do occur, they usually appear 5-15 days from the time you were bitten. Most people who are infected show no or only mild symptoms such as: low grade fever, headache, and occasionally swollen lymph glands. More severe signs and symptoms can include: high fever, stiff neck, muscle weakness, disorientation, brain inflammation (encephalitis), coma and rarely, death. There is no specific treatment for WNV; however, in more sever cases, intensive supportive therapy is needed.

What should I do if I think I have been infected with WNV?

Contact your family physician.

Why are birds being tested for WNV?

They appear to be highly sensitive to the virus and provide a barometer for us to detect WNV activity in your community. Knowledge of positive birds in your area allows mosquito control agencies to perform more targeted surveillance and control activities.

If I live in an area with positive birds and mosquitoes will I get WNV?

It is highly unlikely. Even in areas where mosquitoes do carry the virus very few mosquitoes are infected (less than 1%). If the mosquito is infected, less than 1%of people who get bitten and become infected will get severely ill.

CONTROL AND PREVENTION

What can I do to reduce my risk of getting WNV?

  • Wear long pants and long sleeved shirts when outdoors particularly at dawn and dusk.
  • Make sure screens on windows and doors are in good condition.
  • Use mosquito repellent when outdoors. Be sure to use according to the label – less than 10% DEET for children.
  • Eliminate standing water, old tires, cans and blocked gutters from your property.
  • Maintain your swimming pools. Empty, invert or cover swimming pools when not in use.
  • Keep birdbaths clean. Change the water at least once a week.
  • Report mosquito concerns to your local mosquito control agency.
  • To control mosquitoes inside a house, use a “flying insect spray”. Be sure to use according to directions on the label.

For more information regarding mosquitoes and measures for prevention and control of mosquito breeding, contact Harris County Public Health and Environmental Services Mosquito Control Division at (713)-440-4800 or log on to www.hcphes.org . If you live outside Harris County , please contact your local mosquito control agency, health department or the Texas Department of State Health Services at: http://www.dshs.state.tx.us/idcu/disease/arboviral/westNile/default.asp .

Additional information is available through the Centers for Disease Control & Prevention at: www.cdc.gov/ncidod/dvbid/westnile/index.htm .

For more information contact:
Harris County Public Health and Environmental Services
Mosquito Control Division
3330 Old Spanish Trail, Bldg. D, Houston, Texas 77021
Phone: (713) 440-4800 Fax: ( 713) 440-4795

Back to top

 

Mosquito Control Site Map
| About Us | Site Map | What's New | Divisions | Programs | Publications |
| Jobs || Home | Harris County |

Disclaimer

Last updated:  July 01, 2008 
Harris County Public Health & Environmental Services
2223 West Loop South
Houston, TX 77027
Tel: (713) 439-6000
Webmaster