Mosquitoes trapped in Jackson County last week have tested positive for West Nile virus, 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."
Anyone who notices sick or dead birds such as crows, ravens, jays and robins should call Jackson County Vector Control at 541-779-6460, so biologists can pick them up for testing.
This is the sixth year the virus has been detected locally since 2005, county officials said. Six Oregon counties 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. 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.
"They can develop a range of different symptoms and conditions," said Dr. Emilio DeBess, public health veterinarian for the Oregon Department of Human Services. "A lot of it depends on your immune (system's) condition."
Anyone affected by a severe headache should seek medical treatment, health officials said.
The Vector Control District plans to increase surveillance because of the findings, and officials are asking for the public's help. Anyone who notices sick or dead birds such as crows, ravens, jays and robins should call 541-779-6460 so biologists can pick them up for testing.
Health officials encourage residents to take extra precautions to reduce exposure to mosquito bites. Standing water should be eliminated wherever possible, as it can be a breeding ground for the bugs after just seven days. Spots such as buckets, pool covers, clogged rain gutters, flooded fields and water troughs are common places for water to collect.
Mosquitoes are most active at dawn and dusk. Those venturing outside, especially during those times, should wear long-sleeved shirts and pants in mosquito-infested areas. Repellents containing DEET, oil of lemon, eucalyptus or picaridin are the most effective, health officials said. In addition, screens on doors and windows should fit tightly.
"We always want people to be vigilant," Lunders said. "The big thing is we just want people to protect themselves as much as possible."
Reach Mail Tribune reporter Ryan Pfeil at 541-776-4468 or firstname.lastname@example.org.