Mosquitoes trapped for West Nile virus testing in Jackson County last week have tested positive for the pathogen, Jackson County health officials reported.
The mosquitoes were collected from traps baited with dry ice along Bear Creek in south Medford. The Oregon State University Veterinary Diagnostic Laboratory in Corvallis confirmed the presence of the virus.
"It's not unexpected. This is the time of year when things usually peak. It's not surprising that we're seeing some now," said James Lunders, manager and biologist for the Jackson County Vector Control District. "It's actually a good thing it's this late in the season."
This makes for the sixth year the virus has been detected since 2005, county officials reported. Six Oregon counties total have confirmed the presence of the virus, including Malheur, Baker, Klamath, Umatilla, and Union.
The county's Vector Control District sets 31 adult mosquito traps throughout the county every week. Caught specimens are divided by species, pooled into groups of 30, then sent to the OSU facility for testing.
Health officials said most people infected with the virus do not become sick. Mild flu-like symptoms including fever, headache, body aches, swollen lymph glands or rash are sometimes reported. The virus also can cause inflammation of the brain.
"Fortunately, the percentage of people who have severe symptoms from West Nile Virus is pretty low," Lunders said. "Roughly 80 percent of people that are infected don't know they have it, so they get over it and they're fine."
Anyone affected by a severe headache should seek medical treatment, health officials said.
The Vector Control District plans to increase surveillance within the district because of the findings and officials are asking for the public's help. Anyone who notices sick or dead birds like crows, ravens, jays and robins should contact Vector Control District officials at 541-779-6460 so biologists can pick them up for testing.
— Ryan Pfeil
Read more in Thursday's paper.