West Nile Virus Identified in Clackamas County Bird

There have been no human, horse or other animal cases of West Nile virus identified in Clackamas County.

Image courtesy: uiowa.edu

(MILWAUKIE, Ore. ) - West Nile virus has been detected in a dead crow in the Milwaukie area of Clackamas County, a Vector Control official reported today.

Testing at the Oregon State University Veterinary Diagnostic Laboratory in Corvallis confirmed the presence of the virus. This is the first case of West Nile virus identified in Clackamas County since the virus was introduced into the United States in 1999.

West Nile virus was first identified in Oregon in 2004.

There have been no human, horse or other animal cases of West Nile virus identified in Clackamas County. "We've been expecting West Nile virus to appear in Clackamas County birds at any time since it has been detected in surrounding areas in past years, so this is not a surprise," said District Director Elizabeth Knight. Vector Control officials have actively been collecting, testing and treating mosquito species throughout the county. "This does not necessarily mean that we expect human cases any time soon, but it does mean people need to step up their efforts to protect themselves from mosquitoes." West Nile virus is an infection that lives in birds. It is spread when a mosquito feeds on an infected bird in the Corvid family (such as ravens, crows, jays and magpies) and then bites a human, horse or other animal.

Birds cannot transmit the illness directly to humans, nor is it transmitted from other animals to humans or from person-to-person. People who find a bird that is known to have died due to illness within the past 24 hours should call the Clackamas County Vector Control District at 503-655-8394 to ask about testing.

Only crows, jays, ravens and magpies that have been dead for less than 24 hours will be tested. The best defense for humans against West Nile virus is to prevent mosquito bites.

People can take the following steps to reduce their chance of being bitten:

1. Eliminate all sources of standing water that can support mosquito breeding, such as leaf-clogged gutters, birdbaths and old tires.

2. If possible, avoid being outside at dusk and dawn when mosquitoes are most active.

3. Wear long pants, long-sleeve shirts and other protective clothing while outdoors.

4. Wear insect repellant, preferably one that contains DEET or Picaridin.

5. Follow label instructions when using any repellant.

Further information can be found at: http://oregon.gov/dhs/ph/acd/diseases/wnile/wnvprevent.shtml

6. Make sure that doors and windows have tight-fitting screens.

7. Repair or replace screens that have tears or holes.

A vaccine against West Nile virus has been developed for horses, but there is no vaccine for humans.

Because horses are also at risk for West Nile virus, horse owners are encouraged to check with their veterinarians for vaccination.

Veterinarians can also arrange for testing of samples from horses suspected of being infected with West Nile virus. Most people who are infected with West Nile virus will have no symptoms.

Those that do have symptoms that are usually mild, with fever, headache, body aches and other flu-like symptoms, and occasionally swollen lymph glands or a rash.

In rare cases severe infections may cause encephalitis (inflammation of the brain) and, rarely, death.

The risk of severe illness is greater in persons over 50 years of age. Oregon officials have been monitoring mosquitoes and birds for the appearance of West Nile virus since 2001, and the first case was found in the state in 2004.

Vector control districts throughout the state, including the Clackamas County Vector Control District, routinely collect mosquito specimens which are tested regularly by the OSU Veterinary Diagnostic Laboratory in Corvallis. For more information about West Nile virus, protecting against mosquito bites and what to do if you find a dead bird, contact the Clackamas County Vector Control District at 503-655-8394 or http://www.vectorclackamas.com/ or the Oregon Department of Public Health at http://oregon.gov/DHS/ph/acd/diseases/wnile/wnvprevent.shtml

National information is available at the Centers for Disease Control and Prevention at http://www.cdc.gov/ncidod/dvbid/westnile/index.htm.