WASHINGTON, D.C. -- Cases of West Nile virus have more than doubled over the same time last year, potentially signaling an epidemic in certain areas, according to researchers at the Centers for Disease Control and Prevention (CDC). To date, 185 cases have been registered nationally, up from 87 at the same time last year, with 60 brain infections and five deaths reported this year.
“Given the jump in reported cases, along with the minute chance of developing life-threatening illness, we are asking people in areas where it is prevalent to become familiar with the incidence and symptoms of West Nile virus and to take extra precautions against mosquito bites,” said Brian Keaton, MD, FACEP, president of the American College of Emergency Physicians (ACEP). “These steps are especially important for the elderly, young children and persons with suppressed immune systems.”
The hardest-hit West Nile virus areas to date include the Dakotas, with 52 cases, and California, with 42, but the virus could also spike in other states as peak mosquito season gets underway in August and September. Also, because incidence levels of the virus are subject to change, based on rainfall levels and other variables, ACEP recommends checking the CDC’s West Nile Virus Web site home page at http://www.cdc.gov/ncidod/dvbid/westnile/index.htm for updates and maps.
First reported in the United States in 1999, West Nile virus causes only a mild, flu-like illness 20 percent of the time. Still, the virus is considered a public health concern because of the risk of contracting a potentially fatal brain infection in about 1 percent of cases. In addition, the risk of illness severity is greater for persons over age 50 and for those who are immunocompromised.
Preventing Mosquito Bites is Key
Because West Nile virus is transmitted by mosquitoes, the best way to reduce the chance of becoming infected is to avoid getting bitten. Here’s how:
-- Use insect repellent such as DEET (no more than 10 percent formula for children; not intended for use on infants under 2 months old) or natural oil of lemon eucalyptus (not intended for use on children under age 3) on clothing and skin; for details on insect repellents and usage guidelines see www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm.
-- Eliminate mosquito breeding sites by draining sources of standing water, inserting mosquito larvae pellets in drains, maintaining clean gutters and keeping fountain waters flowing.
-- If possible, cover up; wear long-sleeves and pants when outdoors.
-- Stay inside between sunset and sunrise, when mosquitoes are more prevalent.
-- Install or repair screens on doors and windows to keep mosquitoes out.
-- Investigate and support your community’s mosquito-control program (many communities practice integrated pest management; for details, see www.beyondpesticides.org).
Know the Differences Between Mild and Severe Infection
Since avoiding mosquitoes entirely is nearly impossible, the good news is that West Nile Virus is not a major health concern for most people, first because it is not contagious, and, second, because it tends to be asymptomatic. Among the one in five persons who do fall ill, typical symptoms include fever, headache, fatigue, aches and pains, and, in some cases, swollen lymph nodes and a skin rash on the trunk of the body. These symptoms generally last for only a few days, but in some cases can linger for a few weeks.
West Nile virus infection of the brain and nervous system is rare but potentially deadly. Symptoms include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis. Such illnesses include West Nile encephalitis (inflammation of the brain), meningitis (inflammation of the tissue surrounding the brain and spinal cord) and West Nile poliomyelitis (inflammation of the spinal cord that causes sudden weakness and/or paralysis in the limbs and/or breathing muscles). Severe disease may last several weeks and can be fatal. Because there is no specific treatment available for West Nile Virus infection, prevention of mosquito bites is critical.
“While West Nile virus is not a concern in most cases, it is important to be aware of the symptoms of severe infection and to seek immediate medical attention if those symptoms arise,” Keaton advised.