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DHS News Release


August 31, 2005


Contact: (503) 945-5738

Program contact: Emilio DeBess (971) 673-1027


State reports this year's first four West Nile virus cases in humans



Oregon's first four cases of West Nile virus in humans were reported Wednesday afternoon, prompting state public health officials to advise residents to step up precautions against the infection.


The four cases affect residents of Lane and Malheur counties, both of whom are believed to have been bitten by mosquitoes in Oregon, and residents of Benton and Marion counties, both of whom reported being bitten while traveling in California's central valley.


Emilio DeBess, DVM, state public health veterinarian in the Oregon Department of Human Services, said three of the four people experienced symptoms and have since recovered. The fourth individual was found to be positive after giving blood in Lane County, had no symptoms and reported that he believed he was bitten by a mosquito in Josephine County. Lane County reported the case to the Lane Memorial Blood Bank, DeBess said.


The four cases first tested positive at the state public health laboratory in Portland, and were subsequently confirmed using U.S. Centers for Disease Control and Prevention testing procedures at a federally supported lab in Richmond, Calif. The Benton and Lane cases were in men, the Marion and Malheur cases in women. All three persons who experienced symptoms had fever and weakness, and one also developed a rash.


DeBess said the California lab is now testing a number of other Oregon cases, although it's unclear how many of them might be confirmed as positive. Four human cases were reported in Oregon during all of 2004.


He said the human cases are a signal to Oregonians to take precautions against the mosquito-carried infection:


  • Ensure that screen doors and windows fit tightly; repair or replace screens that have tears or holes.
  • Wear long pants, long-sleeved shirts and other protective clothing when outdoors.
  • Eliminate all sources of standing water that can support mosquito breeding such as clogged gutters, bird baths and old tires.
  • Avoid playing or working outside at dawn or dusk, times that mosquitoes are most active.
  • Use repellants that contain DEET, Picaridin or oil of lemon eucalyptus, following label directions carefully. Never apply DEET directly to children's skin, however; apply repellant first to your own hands and then onto the child. Don’t use oil of lemon eucalyptus on children under age 3.


In humans, the effects of West Nile range from an infection without symptoms to fever and, in the most serious cases, encephalitis and even death.


Of the five 2004 human cases in Oregon, three had symptoms of the infection and two did not. Four lived in Malheur County, the fifth in Jackson County.