TIMELY TOPICS:

Newly Emerging Infectious Diseases (Part 2)

Howard G. McQuarrie, M.D.
Medical Director, PEHP

Newly Emerging Infectious Diseases (Part 1)
Newly Emerging Infectious Diseases (Part 3)

Introduction: WEST NILE VIRUS

A geographically spreading infectious disease called West Nile virus (WNV) is a potentially serious illness. Experts believe WNV is established as a seasonal epidemic in North America that flares up in the summer and continues through the fall. There are effective methods for preventing the disease but no known method for treating the infectious process, once established. However, a promising new vaccine may be emeging to stop the virus, which is spread to the animal population and occasionally to humans by mosquitoes that bite infected birds.

Symptoms of West Nile Virus. People typically develop symptoms between 3 and 14 days after they are bitten by an infected mosquito.

• No symptoms in most people. Eighty percent of people who are infected with WNV will not show any symptoms at all.
• Mild symptoms in some people. Up to 20 percent of people who become infected will display mild symptoms, including fever, headache and body aches, nausea, vomiting and sometimes swollen lymph glands or a skin rash on the chest, stomach, and back. Usually symptoms last a few days.
• Serious symptoms in a few people. About one in 150 people infected with WNV will develop severe illness. The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.

How WNV spreads

• Infected mosquitoes. Generally, WNV is spread by the bite of an infected mosquito. Mosquitoes are WNV carriers that become infected when they feed on infected birds. Infected mosquitoes can spread WNV to humans and other animals when they bite.
• Transfusions, transplants, and mother-to-child. In a very small number of cases, WNV also has spread through blood transfusions, organ transplants, breastfeeding, and even during pregnancy from mother to baby.
• Not through touching. WNV is not spread through casual contact such as touching or kissing a person with the virus.

How is WNV Infection Treated?
There is no specific treatment for WNV infection. In cases with mild symptoms, people experience symptoms such as fever and aches that pass on their own. In more severe cases, people usually need to go to the hospital where they can receive supportive treatment including intravenous fluids, respiratory therapy and nursing care.

What should a person do if he or she thinks they have WNV? For those with mild symptoms, persons do not necessarily need to seek medical attention. When severe symptoms are present, one should seek medical attention immediately due to the rapid progress of the disease. Pregnant women and nursing mothers are encouraged to talk to their doctor if they develop symptoms that could be WNV. The greatest risk is for those who spend a great deal of time outdoors and who are over the age of 50. If symptoms are highly suspicious, your doctor may order a laboratory test to confirm or rule out the presence of the virus.

What can be done to prevent WNV?

• When you are outdoors, use insect repellents containing DEET. Follow the directions on the package.
• Spray permethrin clothing spray (“Fite Bite”) insecticide on clothing. This is an effective insecticide for mosquitoes and ticks. Mosquitoes are most active and threatening at dusk and dawn.
• Consider staying indoors during these times or use insect repellent and wear long sleeves and pants when outside. Light-colored clothing can help you see mosquitoes that land on you.
• Make sure you have good screens on your windows and doors to keep mosquitoes out.
• Remove mosquito breeding sites by emptying standing water from flowerpots, buckets and barrels. Change the water in pet dishes, and replace the water in bird baths weekly.
• Drill drainage holes in tire swings so water drains out. Keep children’s wading pools empty and on their sides when they aren’t being used.

If you find a dead bird, don’t handle it with your bare hands. Contact your local health department for instructions on handling.

References:

http://www.cdc.gov/ncidod/dvbid/westnile/wnv_factSheet.htm (Center for Disease Control)
Cbarton@utah.gov (Utah Department of Health)

Also see the Timely Topics Archive

Other Valuable Health Resources

• The book: Health Tracks, A Practical Guide to Managing Your Health (PEHP) – available from your employer/Human Resource Department or through this website.
• There is now new and updated information regarding cholesterol, and how it relates to coronary artery disease and its associated risk factors. This important information is covered in the article below (in Adobe Acrobat format). This copyright-free document has been produced by the National Cholesterol Education Program, and released by the National Institutes of Health (NIH). It is in an easy-to-read and understand format, and is recommended for everyone.