| ||||
|
|
West Nile risks worse than some believe
Many Americans may not be "getting" the fact that precautions really are necessary. West Nile virus can be devastating for humans, as well as horses and birds.
West Nile expert Ludek Zurek says that many Americans don't seem to realize the dangers.
If nothing else, scientists continue to discover just how profound the virus' effects can be, said Zurek, the medical-veterinary entomologist for Kansas State University Research and Extension.
The mosquito-borne virus first appeared in the United States during the summer of 1999 in New York City. Even then, West Nile was known to occasionally lead to meningitis (inflammation--swelling--of the membranes around the brain) or viral encephalitis (inflammation of the entire brain).
So why haven't more Americans acknowledged it and worked to reduce such risks?
Several things could be contributing to the problem:
Each spring, birds and then horses fall victim to the virus first and thus make the news first. On April 28, 2004, the U.S. Centers for Disease Control and Prevention reported that eight states--Alabama, California, Florida, Georgia, Louisiana, New York, Pennsylvania and Texas--had already registered positive test results for 2004's round of West Nile virus in mosquitoes, birds and horses. One state, Ohio, had identified the year's first human case.
"In Kansas, humans are most at risk from June through September. That's when the year's mosquito populations peak, and that's when people spend more time outdoors," Zurek said.
In addition, fatality statistics are much worse for birds and horses.
Among certain bird species--notably crows, ravens, bluejays and prey- eating raptors (hawks, eagles)--contracting West Nile is a likely death sentence, Zurek said.
For the virus to travel to other populations, a mosquito must bite an infected, but still living bird. The mosquito then can transfer the virus to horses or humans, he said.
Two vaccines currently are available for horses. Vaccinations are why Kansas went from having 800 horses contract West Nile in 2002 to 80 cases in 2003, Zurek said. Among unvaccinated horses that get infected, however, about one-third die.
In contrast, a vaccine for humans is still in the testing phase. But, the great majority of humans who get West Nile will either develop no symptoms or believe they have a mild case of flu.
The CDC reports that less than 1 percent of humans who become infected with the virus will also develop a severe illness. Among those, the fatality rate will range from 3 to 15 percent, with the elderly being at highest risk.
Health officials have worked hard to warn people, but not make them panic.
Even so, the health consequences for humans can be so serious that people need to take precautions, Zurek said.
People who contract the virus apparently also develop a long-lasting immunity, and about four out of five of them will display no symptoms. But up to 20 percent will develop such symptoms as fever, headache, other aches, nausea, vomiting, swollen lymph glands or a rash that last from a few days to several weeks.
Although most will not die, about one in 150 infected people will need to be hospitalized with symptoms such as high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, numbness, convulsions, muscle weakness, vision loss and paralysis. The neurological effects may be permanent.
Zurek has met several victims who've survived West Nile-caused encephalitis.
"They had no words to describe how extreme the pain was. The best they could do was to say that their head literally felt as if it were going to explode," he said.
Almost as bad for the entomologist is knowing that contracting the virus is preventable--if people take the risks seriously.
"It simply requires removing or otherwise taking care of all the standing water that can serve as mosquitoes' breeding ground," Zurek said. "Then make sure your window and door screens are tight, and start applying a DEET-based insect repellent when you go outdoors during warm weather, especially at dawn and dusk."
--------SIDEBAR--------
Practical steps to prevent West Nile virus
Eliminating all mosquitoes is a practical impossibility, according to Ludek Zurek, entomologist with Kansas State University Research and Extension. But people can take other steps that significantly reduce the odds for mosquito-borne illness, including West Nile virus:
--For standing bodies of water such as decorative ponds or livestock tanks, buy some guppies or goldfish--which feast on mosquito larvae. Or, buy an appropriate dunk, doughnut or briquette containing B.t.i. (Bacillus thuringiensis israelensis) and carefully follow its label directions.
--For smaller water holders such as birdbaths, children's play pools and unused fountains, clean them out and replace the water at least once a week.
--Keep "incidental" water holders empty or put away. This can include toys, old tires, wheelbarrows, buckets, tree holes, flower pots, clogged gutters, holes in the ground, lids, concave rocks, watering cans and plastic covers.
--Make sure door and window screens are "bug-tight."
--During the warm months, try to avoid going outdoors during the early morning hours and in the evening. That's when mosquitoes are most active.
--If you'll be outdoors during mosquito season, apply a DEET-based repellent to exposed skin and clothes. If you can, also wear a long-sleeved shirt, long-legged pants and socks. The amount of DEET in a product relates only to the time it will last, not the protection it provides. Children should use a product that contains less than 10 percent DEET or one of the soy oil-based repellents.
More detailed information is available in Zurek's publication "Pests That Affect Human Health: Mosquitoes and West Nile Virus" (MF-2571).
It's available at any Kansas county's K-State Research and Extension office or on the Web at www.oznet.ksu.edu/library/ENTML2/MF2571.pdf .
Date: 5/19/04
Copyright 1995-2008. High Plains Publishers, Inc. All rights reserved. Any republishing of these pages, including electronic reproduction of the editorial archives or classified advertising, is strictly prohibited. If you have questions or comments you can reach us at High Plains Journal 1500 E. Wyatt Earp Blvd., P.O. Box 760, Dodge City, KS 67801 or call 1-800-452-7171. Email: webmaster@hpj.com
 
| |||||||||||||||||||||
