September 9, 2002 The Capital Times by David Marcelis
WASHINGTON - The president of a private lab near Milwaukee says
hunters wanting to know if their deer have chronic wasting disease
can find out from his lab in as fast as one week using a new "rapid"
test for the fatal brain disease.
Wildlife Support Services President William Johnson said the lab will be able to process about 1,000 samples a day, so hunters may wait from one to five weeks if the lab gets, say, 25,000 samples. The Department of Natural Resources has reported that hunters waiting for results from the state's lab may have to wait between three and six months.
Johnson's predictions come despite a warning last week from Assistant State Veterinarian Bob Ehlenfeldt that hunters should be wary of private tests not accredited by the U.S. Department of Agriculture.
"Go do your hunting and leave meat in the freezer and wait for your county results," Ehlenfeldt told a group of legislators Thursday.
But Wisconsin testers plan to use the new rapid tests, too, although in a limited capacity.
The Wisconsin Veterinary Diagnostic Laboratory, which is to be accredited by the USDA as an official chronic wasting disease testing site, will mostly use the standard test known as the immuno-histochemistry test. But the lab will also perform parallel testing with the rapid test, according to chief pathologist Philip Bochsler.
The lab is expected to test around 50,000 samples during the hunting season.
Bochsler said doing rapid testing on the side will help the technology get recognition.
"If they are good, accurate tests ... that would provide another way for us in the state to do the testing, maybe more efficiently," Bochsler said.
The laboratory will use similar rapid testing devices provided by three different companies. No rapid test has received a license from the Center for Veterinary Biologics of the USDA yet, but rapid tests can be used if they're not the prime testing method.
Experts say results from the rapid test are available in about a day. The standard test takes approximately one week, but could be delayed much longer during hunting season due to the high volume of tests, according to Kimberley Smith, spokeswoman for the USDA's Animal and Plant Health Inspection Service.
Wildlife Support Services will use a rapid test system as its main testing device, Johnson said, but he added that they will perform IHC tests on positive results as well as randomly on 10 percent of overall results for quality control purposes.
Johnson said the lab won't be accredited by the USDA, like all other private labs, but he added that he will also notify the USDA of his lab's results.
Johnson said the rapid test has been specifically designed for chronic wasting disease. Although the rapid test device hasn't been licensed yet, Johnson said he was working on it.
Marshfield Laboratories, a division of the Marshfield Clinic, also plan to test for chronic wasting disease, but the lab will first seek USDA's accreditation and will use the IHC as its main device, according to Frances Moore, director of the veterinary division of the laboratories.
The lab is also planning to use rapid tests as soon as they're licensed.
"Rapid is a funny term," Bochsler said. "Rapid, to most people, means something that's really quite quick, like a pregnancy test. But it's not that quick. It's faster than (the current system) but it still takes a day to do the test."
Results using the standard test from deer killed in the eradication zone during the third week of July were only announced on Aug. 30. But according to Julie Langenberg, veterinarian with the Wisconsin DNR, what takes time is not performing the IHC test itself, but rather getting the sample ready to be tested.
Langenberg said once the deer is killed, a piece of the brain stem or lymph nodes of the animal is collected and put into formalin. The DNR then needs to slice the tissue and send it to a USDA-approved lab in Ames, Iowa, where all samples are looked at through a microscope. Thirty-one deer have tested positive so far in Wisconsin.
According to Moore, the way the rapid test works is similar to the IHC test. The major difference, she said, is that the rapid test would allow several brain tissues or lymph nodes to be tested at once.
"No matter how many IHC (tests) you do, you get no benefit of doing larger volumes because each one has to be processed as an individual," Moore said. The rapid test "is not as labor-intensive and (easier) for doing high-volume testing than is the IHC ... because you're not eyeballing each specimen under the microscope, you're actually using a plate reader to read them in the end."
Some companies are currently working on rapid testing devices that wouldn't require such processing, namely by relying on other samples from the animal, such as blood or urine.
According to Antonio Milici, chairman and CEO of Genethera Inc., a Wheat Ridge, Colo.-based company developing a rapid blood test, using blood samples rather than brain tissues has many advantages: The average test would take four hours, several samples could be tested at once and the testing equipment could fit in a trailer, allowing on-site testing.
Furthermore, Milici added, "it doesn't matter if the animal is killed, you can go and draw the blood without killing the animal."
Milici said his company isn't performing any kind of official chronic wasting disease testing yet. Genethera still hasn't applied for a license from USDA's Center for Veterinary Biologics.
According to Langenberg, however, rapid tests using brain tissues or lymph nodes have proven to be more reliable, at least so far.
"Most of the most promising rapid tests, meaning the ones that are going to be in our hands the fastest, are based on tissues, not blood," she said.