Region prepares for West Nile Virus

West Nile Virus is heading for Oregon this summer, borne on the wings of migrating birds coasting up the Pacific Flyway from Mexico.

Deschutes County officials are keeping a wary eye out, but they are not planning any major action, at least not yet.

West Nile Virus (WNV) is a from of encephalitis transmitted by mosquitoes that have fed on infected birds. It can cause serious illness or death in humans and it is particularly lethal to horses.

"This is a disease that is transmitted between mosquitoes and birds and humans just happen to get in the way," said State Public Health Veterinarian Dr. Emilio DeBess at a county forum on Wednesday, April 30.

DeBess and other officials emphasized that there is no reason to panic over the disease. Most people who are bitten by an infected mosquito won't show any symptoms, DeBess noted. Some will get sick with flu-like symptoms including a severe headache.

Some will develop full-blown encephalitis symptoms with swelling of the brain lining and some of those will die.

According to DeBess' statistics, there have been 4,161 human cases of WNV in 39 states and the District of Columbia since the disease appeared in the eastern United States in 1999. There have been 277 deaths; a 6.7 percent mortality rate.

The low mortality rate shouldn't make people complacent, however. Four Rivers Vector Control Manager Bruce Landolt, who is leading local surveillance programs to combat the disease, noted that surviving a severe case of WNV is no blessing.

The long-term effects of the disease can be devastating, leaving victims unable to walk or feed themselves.

"I'm not in fear of death from this disease," Landolt said. "It's the thought of lying on a bed for the next 20 years in a pair of diapers."

Landolt is Central Oregon's front line of defense against WNV. He is under contract to survey for the presence of the mosquitoes that transmit WNV.

Fortunately, Central Oregon is home to only four of the 10 species that are known to transmit the disease -- Culiseta inornata; Aedes vexans; Ochlerotatus dorsalis; and Culex tarsalis.

Of those four, only Culex tarsalis has a high rate of transmission.

These mosquitoes are a known presence in the south part of Deschutes County. Landolt's surveys of the north county are just getting underway.

Mosquitoes are an annoying constant in the summer months even around high mountain lakes. But they do not appear to be the dangerous types.

"I'm not personally too concerned about hiking in the High Cascades," Landolt said.

Deschutes County will not launch a pesticide spraying campaign to ward off WNV -- at least not yet.

According to Health Department Director Dan Peddycord, spraying is an expensive "shotgun approach" that might not be necessary.

However, Landolt is already under contract to spray for mosquito larvae in several areas, including around Black Butte Ranch west of Sisters.

Landolt will conduct his mosquito surveys to identify likely areas of infection and county officials will keep an eye out for die-offs in bird populations -- particularly the corvids such as ravens.

Mass die-offs of birds are usually the first clear indicator that West Nile virus has arrived.

In the meantime, horse owners are advised to get their horses vaccinated against the disease. According to Dr. DeBess, the vaccine is highly effective.

Like humans, many horses that are bitten by infected mosquitoes do just fine -- they never display symptoms.

But those that do get sick are likely to die or will need to be put down.

The neurological effects of the disease often leave horses unable to get up off the ground and, DeBess said, "as soon as a horse goes down, the likelihood of survival is pretty low."

All the officials at the forum recommended using an insect repellent containing a high percentage of DEET. Peddycord said that studies have failed to back up early fears that DEET could be harmful to humans.

Landolt -- who probably has more exposure to mosquitoes than anyone else in Deschutes County -- said he uses DEET with complete confidence.

(For more information on protection from mosquitoes see story below).

Protect yourself from West Nile virus

West Nile is transmitted by mosquitoes that acquire the virus from infected birds. While humans and horses are infected by the virus, they cannot spread the virus to humans or other animals.

To protect yourself from West Nile virus, the Oregon Department of Human Services recommends eliminating potential mosquito breeding areas.

Mosquitoes must have standing water to breed.

Get rid of water where mosquitoes can lay their eggs.

Remove old tires, buckets, cans, chums, bottles or any containers that hold water.

• Fill or drain any low spots in your yard.
• Cover trash containers.
• Inspect rain gutters and downspouts and remove leaves and other debris.
• Empty stagnant water in bird baths, plant posts, rose cuttings, drip trays, small wading ponds, pet dishes and other containers once a week.
• Repair leaky faucets.
• Properly maintain and treat your pool.

  Cover pools not in use to prevent accumulation of leaves and debris.

  Be sure pool covers do not hold pockets of water

• Clean flat roofs and air conditioner drains frequently.
• Eliminate water-holding tree stumps, and fill holes in trees.
• Plant mosquito fish in water troughs and ornamental ponds.
• The first line of defense against mosquito-home diseases is to avoid mosquitoes.
• Apply insect repellent sparingly to exposed skin.

The more DEET a repellent contains the longer it can protect you from mosquito bites. Repellents may irritate the eyes and mouth, so avoid applying repellents to the hands of children.

Be sure to read and follow the manufacturer's directions for use, as printed on the product.

• When possible, wear long-sleeved shirts and long pants when you are outdoors.
• Place mosquito netting over infant carriers when you are outdoors with infants.
• Consider staying indoors at dawn, dusk and in the early evening, which are peak mosquito biting times.
• Install or repair window and door screens so that mosquitoes cannot get indoors.
• Report die-offs of the corvid family of birds (crows, magpies, ravens, jays) to the local vector-control district or the local county health department.

Be careful when handling dead birds.

Information provided by the Oregon Department of Human Services. Visit the DHS website at www.dhs.state.or.us.

Author Bio

Jim Cornelius, Editor in Chief

Jim Cornelius is editor in chief of The Nugget and author of “Warriors of the Wildlands: True Tales of the Frontier Partisans.” A history buff, he explores frontier history across three centuries and several continents on his podcast, The Frontier Partisans. For more information visit www.frontierpartisans.com.

• Email: editor@nuggetnews.com
• Phone: 5415499941