West Nile Virus Update, by Darcee Dunkle, RN

It is time to revisit this subject, as West Nile Virus (WNV) is once again rearing its ugly head. WNV first appeared in Pennsylvania in 2000. It is transmitted primarily by mosquitos and affects humans, as well as birds, horses, and chickens. As of September 29, 2003, WNV had been detected in every county in Pennsylvania.

Signs and symptoms of WNV in humans may include fever, headache, body aches, skin rash, weakness, swollen lymph glands, nausea, vomiting, and diarrhea. The incubation period is from three to fourteen days. About one in 150 people infected with WNV will have severe health problems, incuding meningitis or encephalitis. Most people will experience only mild symptoms. People over 50 have the highest risk of developing WNV because as we get older, our bodies have a harder time fighting off infection and disease. People with compromised immune systems are also at increased risk.

Treatment is mainly supportive. In other words, doctors treat the symptoms. There is no vaccine as yet. Most people will have a full and complete recovery from WNV. Approximately 25% of those infected with WNV will require intensive care treatment and 10% will require machanical ventilation. There have been five deaths in Pennsylvania so far in 2003.

To decrease the risk of developing WNV, we need to reduce the number of mosquitos around our homes and neighborhoods. Mosquitos lay their eggs in stagnant water around the home, so we can go a lont way to prevent WNV. Ways to accomplish this include: disposing of tin cans, plastic containers, ceramic pots, and other water-holding containers; pay special attention to discarded tires on your property; drill holes in the bottom of recycling containers that are left outdoors; clean clogged roof gutters.

There is also a product available for home use called Bti, which has been used by mosquito control professionals for years to kill mosquito larvae. Bti is a naturally occuring bacteria and can be purchased as a "mosquito dunk" or in granular form. The mosquito dunk is a small, donut-shaped form that can be placed in small areas of standing water, such as bird baths. The granular form can be used for larger areas of standing water, such as ponds. Bti is not harmful to people, pets, aquatic life, or plants; it only kills mosquito and black fly larvae. Bti can be purchased at lawn and garden stores, outdoor supply stores, and home improvement stores.

We also need to take normal steps to prevent insect bites. Wear shoes, socks, long pants, and long sleeves when you are outdoors for long periods of time, or when mosquitos are most active. Use insect repellent with 20% - 30% DEET. Also spray your clothing with insect repellent. Do not apply to children less than two years old. When possible, avoid exposure, especially at dawn, dusk, and early evening during peak mosquito periods of April through October. Make sure you have tight-fitting screens over windows and doors to help keep mosquitos from entering apartments and homes.

Electromagnetic and ultrasound devices, Vitamin B, citronella candles, and plant-derived repellents are not effective in preventing mosquito bites. These items may provide you with short-term protection, but do not have the longer-lasting effect that DEET does.

In conclusion, you can greatly lessen your chances of being bitten by an infected mosquito if you follow the guidelines listed above. If you are bitten, remember, not all mosquitos are infected. Most people who get WNV will exhibit only mild symptoms. If you do develop a high fever, extreme weakness, severe headaches, uncontrollable nausea, vomiting, or diarrhea, contact your doctor.