West Nile Virus - Colorado College

West Nile virus (WNV) is a virus that is spread to humans by the bite of an infected mosquito and is potentially a serious illness. Experts believe WNV is established as a seasonal epidemic in North America that flares up in the summer and continues into the fall. Colorado Springs had cases in the summer of 2003 in both animals and humans. Biting mosquitos usually disappear by mid-September.

How does West Nile spread?

• Infected mosquitos. 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 then spread WNV to humans and other animals when they bite. Individuals over age 50, small children, pregnant women, and those with poor health are most at risk for serious complications, however, anyone can become infected.



• 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.

Symptoms of WNV

WNV affects the central nervous system. Symptoms vary. People typically develop symptoms between 3 and 15 days after the infected mosquito has bitten them.

No symptoms in most people. Approximately 80 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 the people who become infected will display mild symptoms, including fever, headache, body aches, nausea, vomiting, swollen lymph glands or a skin rash on the chest, stomach and back. Symptoms typically 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.

Seeking treatment

Mild WNV illness improves on its own and people do not necessarily need to seek medical attention for this infection. In cases with symptoms that include severe headaches or confusion, seek medical attention immediately.

Prevention is the key

Wear long sleeves and long pants at dusk and dawn when mosquitos are more likely to bite. Use DEET insect repellent. The stronger the percent of DEET, the longer it will last. Natural repellents such as Citronella do not appear to be effective. Wash DEET off when not needed. For more information on WNV, visit the Centers for Disease Control at www.cdc.gov/ncidod/dvbid/westnile/, Colorado Department of Public Health and Environment at www.cdphe.state.co.us, or El Paso County Health Department at www.elpasocountyhealth.org; West Nile hotline - 1-877-462-2911.