The origins and future of West Nile virus

By University of Illinois Extension — Boone, DeKalb and Ogle Counties

West Nile virus was first detected 75 years ago in Uganda. The virus spread throughout the world and most recently, 13 years ago, to North America.

There is controversy as to how the illness came to our country. Some believe it came from migratory birds who acted as the host. Other scientists believe the eggs and/or larvae of the tiger mosquito traveled in stagnant water found in old tires or other water-holding cargo on ships from Asia.

No matter the form of transportation, West Nile now resides and has been detected in many species of mosquitos, animals and humans in the United States.

West Nile virus is carried by birds and other animals but transmitted only by mosquitoes. A human being or animal contracts the disease when they are bitten by a mosquito that is infected. Not all animals that contract the virus show symptoms.

There is the probability that some birds are simply hosts for the disease, therefore increasing the consistent availability for it to be picked up by more mosquitos,” said Peggy Doty, University of Illinois Extension.

After being identified in New York City in 1999, West Nile has since managed to travel to at least 47 states and into Canada.

Though mosquitos do not travel as far as their winged hosts, many birds not only fly many miles within their home range, but the majority of our birds in the United States migrate to other states and countries,” Doty said. “West Nile has chosen the most efficient group of animals to use as its main host.”

Like other animals, the majority of humans are never infected with the virus, and those who actually contract the virus rarely show symptoms, let alone become seriously ill. Eighty percent of those who are bitten by an infected mosquito never have any symptoms of West Nile. Young children, the elderly and people with an impaired immune system are at the greatest risk. Your best defense against the disease is to avoid being bitten by mosquitos.

People are responsible for themselves and others when viruses like this occur. For yourself, wear loose, long-sleeve shirts and pants when mosquitos are in the area of your choice activity. If you spray repellent, use it on top of your clothing. Never spray a repellent with DEET on your skin and then cover it with long clothing. This could actually cause a severe reaction. DEET should also never be applied to your face or pets. Any skin sprayed with DEET should be washed off when you return indoors.

According to the Center of Disease Control, symptoms of West Nile can range from a simple fever for a few days while others may also get a headache, body ache, swollen lymph glands and occasionally a rash on the trunk of the body. These symptoms may appear in three to 12 days and can take a few days to disappear. If you go to your physician and West Nile is a concern because of your encounter with mosquitos, let them know so they can run proper blood work to check for the virus.

To do your part in the community, eliminate any water-retaining items in your yard such as tires, garden décor that may hold any amount of water as well as any other items that capture and hold water for more than a day. If you have bird baths, small children’s pools, pet water bowls or other items that must have water in them simply change the water daily. If you have a decorative pond, simply add a fountain or anything that moves the water daily to discourage mosquitos from laying eggs there.

Putting a fountain or pump on a timer is the easiest way to keep your water feature and not worry about breeding mosquitos,” Doty said. “I have a pump set to come on from 4 in the afternoon until midnight and then again from 6 to 8 in the morning, the times when mosquitos are most active, and that seems to keep the them from being interested in it,” Doty said.

Doty added: “West Nile will most likely persist in our environment and will fluctuate in its intensity of cases as the weather changes year to year. The drought will make it more difficult for the disease to spread due to the lack of mosquito numbers, but the birds who carry the disease may be migrants who will bring it back with them in the spring.”

From the Sept. 5-11, 2012, issue

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