Gazette-Times reporter

After two confirmed rabies cases involving Benton County bats in two weeks, Alpine retiree Dan Settle was more than a little concerned this week when he opened his barn door and a bat fell on his head, bounced off his arm and hit the floor. He covered the animal with a fishing net and made a phone call to the county Health Department.

But health officials - who earlier this month had tested two bats that came into contact with domestic pets and determined that both were rabid - didn't want this bat. Turn it loose, they said.

But Settle was concerned about the bat's health.

"It just didn't act like a wild animal would act," he said. "It wasn't very responsive to what was going on. The bat just laid on the ground and hissed occasionally.

"With the story of the rabies going around, I just didn't think it was right to let it loose," he said.

According to the county Health Department, it's not as simple as finding a strange-acting bat and taking it in for testing. The Oregon Department of Human Services sets strict guidelines for figuring out whether actual contact occurred.

"If there had been an actual bite with saliva exchange, that would be different," said Bill Emminger, Benton County Health Department director. "From strictly a wildlife biology standpoint, it might be interesting to test the bat, but we're in the business of protecting public health."

In nearly all cases, it is actually up to the person coming into contact with the bat to pay for testing.

A rabies test at the Oregon State University Veterinary Diagnostics Laboratory costs $70. Jerry Heidel, director of the lab, said it is among the most expensive disease tests.

The rabies vaccination for humans, on the other hand, is a series of five shots over five weeks and can cost upwards of $1,500.

The OSU diagnostic lab does virtually all of the testing for rabies in the state of Oregon and much of Washington. Heidel said the test takes three to four hours to complete and few other labs want to risk a misdiagnosis, so the OSU lab takes the cases.

At the lab, brain matter from a suspected rabies carrier is collected and placed onto a glass microscope slide. Technicians add rabies antibodies that have fluorescent dye attached to them and then watch to see if the antibodies converge on the virus.

Antibodies are proteins in the bloodstream that are used by the immune system to fight off disease.

"We take very strict precautions to make sure our results are accurate," Heidel said.

Settle said he didn't want to kill the bat outright, so he kept it under the net waiting for something to happen.

Emminger said it's not uncommon for people to see more bats in the fall, when old or sick bats start to die off before winter. The bats are then more likely to come in contact with people or animals, as in the two recent rabies cases in Benton County.

On Sept. 13, a bat that later tested positive for the rabies virus was found in the mouth of a cat near Fourth Street and Polk Avenue in Corvallis. The cat had been vaccinated against the disease.

The second bat was found Sept. 21 by a dog outside the Finley Wildlife Refuge about 10 miles south of the city and nearer to Settle's Alpine home. Unfortunately, the dog was not vaccinated against the disease.

Animals that have been vaccinated are watched for a 10-day period to see if they get sick. Those that aren't up to date on their shots are typically destroyed, since the other option - six month quarantine - is difficult and expensive.

Emminger said if a person or an animal didn't have a bite or scratch, the usual next step is to let the animal go.

In Settle's case, he knew the bat hadn't bit him. But when someone wakes up to find a bat in their room or finds a bat near a baby, there's reason for alarm.

"Sometimes we get into some gray area," Emminger said. "If there's reasonable doubt that there's been exposure we start the person on the rabies series of shots."

On Thursday, Settle's bat found some new strength, a hole in his fishing net and freedom.

"They told me to keep it away from my animals," Settle said. "Good luck."

Reporter Matt Neznanski can be reached at 758-9518 or matt.neznanski@lee.net.

Rating Rabies Risk

For public health purposes, rabies bites are classified into three categories: high risk, low risk and no risk. The Oregon Department of Human Services admits that the boundary between each category is hard to define, but gives the following criteria for public health officials:

• Was there sufficient exposure to animal saliva?

• Is there a significant risk that the animal in question had the rabies virus in its saliva when the bite happened?

According to state guidelines, unless an animal bite breaks the skin or saliva came in contact with a scratch, no contact occurred. Guidelines are clear that if no contact occurred, there is no risk.

For information on the Oregon State University Veterinary Diagnostic Lab, call 541-737-3261 or go online to oregonstate.edu/

vetmed/vdl/vdl.htm.