By Laura Jean Whitcomb

Summer is here — and so is West Nile, the viral infection that made national headlines last year.

It’s an epidemic that is not likely to disappear in the near future. “The disease is now endemic in most of the United States and most likely there will be further evidence of West Nile Virus transmission in areas where it was not previously evident,” says Tom Marsh, WNV Program Specialist, NH Department of Health and Human Services (DHHS). State organizations, like DHHS, launched their West Nile education programs and hotlines this spring, hoping to reduce human illness in 2003.

According to the Centers for Disease Control and Prevention (CDC), West Nile is spread by the bite of an infected mosquito. The mosquito contracts the virus from an infected bird and, after 10 to 14 days, the virus can be transmitted to another bird, person or animal that the mosquito bites.

Commonly found in Africa, west and central Asia, and the Middle East, West Nile Virus was first recognized in New York City in 1999 and spread rapidly throughout the eastern half of the country by 2001. In 2002, more than 4,000 Americans became ill and approximately 300 died from West Nile.

Even if a state (like New Hampshire) escaped human illness, authorities did find infected mosquitoes and birds. According to the NH DHHS, the Granite State found its first positive bird for West Nile in September 2000, and by December 2002 had reported West Nile in 119 birds and 33 mosquito pools.

Reduce Your Risk

People may become ill three to 15 days after the bite of an infected mosquito. Most infected people won’t have any symptoms, while others may have flu-like symptoms: mild fever, headache and body aches. West Nile typically lasts only a few days and does not appear to cause any long-term health effects in most healthy people.

West Nile can strike any age, but those most at risk are the very young or the very old.
It can cause encephalitis (an inflammation of the brain) or meningitis (an inflammation of the covering of the brain), resulting in either permanent neurological damage or death.

West Nile Virus was first recognized in New York City in 1999 and spread rapidly throughout the eastern half of the country by 2001. In 2002, more than 4,000 Americans became ill and approximately 300 died from West Nile.

Even during the height of last summer’s epidemic, the CDC notes that less than half of people surveyed took any precaution to avoid mosquito bites and only about a third used repellent containing DEET, which provides the best protection against bites. DEET (the common name for N, N-diethyl-m-toluamide) disrupts the ability of biting insects to detect the source of carbon dioxide — the gas naturally given off by our skin and in our breath — which is what attracts mosquitoes and other insects to us. Insects aren’t killed; they just can’t locate their prey for a period of hours.

The best advice: apply an insect repellent to exposed skin. It should contain 10 percent of DEET for children and no more than 30 percent for adults. Since mosquitoes may bite through clothing, spray your garments as well. (If you spray your clothes, you don’t have to spray your skin underneath.) No need to go overboard in applying — just follow the manufacturer’s directions for use. But watch the clock: repellent protection typically lasts up to six hours following application.

West Nile is a seasonal occurrence — in the New England area you should be on the lookout for those pesky mosquitoes primarily in late summer or early fall. (In southern climates with milder temperatures, it can be transmitted year round.) If it isn’t too humid, it is a good idea to wear long-sleeved shirts and long pants whenever you are outdoors. Head nets are handy to keep the buzzing away from your ears and neck when you are walking the dog or gardening. Play it safe and consider staying indoors at peak mosquito biting times: dawn, dusk and in the early evening.

Clean Up the Yard

Want to do more than just cover up? There are ways to help reduce the risk of West Nile. Here are a few ideas, courtesy of CDC’s Division of Vector-Borne Infectious Diseases, NHStateParks.com and the American Mosquito Control Organization.

▪ Drain sources of standing water to reduce the places where mosquitoes can lay their eggs and breed. Mosquitoes will develop in any water source (even a puddle) that lasts more than four days.
▪ Empty water from flowerpots, outdoor pet food and water dishes, swimming pool covers. Turn over wheelbarrows and pick up children’s toys. Change water in bird baths every three to four days.
▪ Check for clogged rain gutters and clean them out.
▪ Check around faucets and air conditioner units for any leaks or puddles.
▪ Remove discarded tires from your property. The used tire has become the number one domestic mosquito producer in this country.
▪ Look for containers that could collect water (like empty cans) in trash or places that might be hard to see (like under a porch).
▪ Drill holes in the bottom of recycling containers that are left outdoors.
▪ Clean and chlorinate swimming pools and outdoor hot tubs. If not in use, empty and keep covered.
▪ Make your house “bug tight.” Repair door and window screens so mosquitoes can’t get indoors.
▪ Keep your lawn mowed and trimmed. Adult mosquitoes prefer to rest on weeds and other vegetation.

“The bottom line is since the mosquito is the vector (transmits the virus), avoiding being bitten by mosquitoes and reducing the opportunity of mosquito breeding is vitally important in reducing the spread of this disease,” says Marsh.