Other than dealing with an irritating itch and a red bump, most people never gave a mosquito bite much thought until 1999, when West Nile virus, a condition linked to brain infections, first appeared in the United States. Since then, the disease, which is transmitted to humans by mosquitoes, has spread to all of the 48 continental United States. Although it’s potentially serious—177 people died of West Nile virus in 2006—about 80 percent of those infected never become ill or show symptoms.
Individuals who work or spend a lot of time outdoors are more likely to be bitten by infected mosquitoes. Symptoms typically appear within three to 15 days of being bitten and may include fever, headache, body aches, nausea, vomiting, swollen lymph glands or a skin rash lasting a few days. In most cases, the illness proves mild and most people fully recover.
Of those who acquire West Nile, a small number—one in 150—develop more serious illnesses, including encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes and fluid surrounding the brain and spinal cord). People over age 50 or those with weakened immune systems are more apt to develop serious symptoms of West Nile virus such as high fever, headache, stiff neck, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. As yet, no specific treatment exists for West Nile virus. Those who develop severe infections may be hospitalized to receive intravenous fluids, pain medication or breathing support.
Simply put, the best way to prevent West Nile infection is to avoid mosquito bites. The virus itself resides primarily in wild and domestic birds—most commonly in crows—but is spread to humans by mosquitoes. Many local public health departments strive to eliminate mosquito breeding grounds—anywhere stagnant water collects—and use larvicide to kill mosquito larvae before they develop into adult insects. Some communities routinely spray pesticides, too. Here’s what you can do to avoid becoming infected:
- Eliminate any standing water in your yard. Unclog gutters; empty water from buckets, wading pools, flowerpots and wheelbarrows; drill drainage holes in tire swings; and change water in birdbaths weekly.
- Keep screens on windows and doors in good condition.
- Avoid spending time outside during early morning and evening hours when mosquitoes are most active.
- Wear light-colored, long-sleeve shirts and long pants when trekking into woodsy areas.
- Apply an insect repellant that contains DEET.
- Report sick or dead birds to your local health department.