Iowa State University


Inside Iowa State
December 8, 2000

Lab checks all creatures great and small

by Teddi Barron
Every dog, cat, pig, cow, horse, hawk, deer, duck, chicken, rabbit, turkey, turtle, tiger, giraffe, zebra, elephant and parakeet in the state of Iowa have one thing in common: Iowa State's Veterinary Diagnostic Laboratory (VDL).

When an animal in Iowa needs to be checked for a virus, bacteria, toxin, infection, cancer, allergen, disease, or just because the law says so, the test most likely is performed and the diagnosis determined by the 85 faculty, staff and students at the VDL.

Every state has a diagnostics laboratory, says Dr. Gary Osweiler. Osweiler is a professor of veterinary diagnostic and production animal medicine and has served as the VDL director for six years.

"These labs help veterinarians and their clients detect and prevent disease by providing diagnostic services that are accessible, timely and accurate," Osweiler said. "The labs also help reduce the incidence and threat of diseases that can be transmitted from animals to humans and they aid in early recognition to prevent the introduction and spread of exotic, foreign or new diseases."

In a state that has more pigs than people, preventing the spread of disease in livestock herds is critical. That means there's a great deal of testing and diagnosing to be done. In fact, Iowa State's VDL manages about 50,000 cases and performs about 1.2 million tests in an average year.


Epidemic threatens
This year, however, has been any-thing but average. With a pseudo-rabies epidemic threatening Iowa's pork industry last spring, the Legislature tightened testing requirements to detect the highly contagious disease in swine herds.

During June, the VDL performed 177,145 pseudo-rabies serology tests. In a typical June, the lab processes about 46,000 serology tests, in which blood serum is checked for antibodies to a specific disease.

"The state's new pseudorabies test requirement had a huge impact on the lab during the summer," Osweiler said.

To handle the unprecedented volume of test submissions, Osweiler hired three new staff members to run tests and help manage the enormous number of mandated regulatory reports. Two new high-speed fax machines dispensed tens of thousands of test results from the VDL conference room, which was converted into a sort of command center during the height of the deluge.

While the serology lab is ground zero for pseudorabies testing, it's only one of six diagnostic sections within the 30,000-square-foot VDL: bacteriology, virology, toxicology, chemistry and pathology are the other specialties.


Samples arrive
Arriving via UPS, or dropped off by a veterinarian en route to a Cyclone football game, specimens are submitted to the VDL for one of two reasons: either a specific test, like rabies, or a diagnosis of an undetermined illness.

The diagnostic process begins in pathology, Osweiler said.

"Pathology is the study of disease. When something comes in, the pathologist looks at the history of the animal, decides what the problem might be and orders the relevant tests. The pathologist sends the appropriate samples to the different sections in the lab."

Although "there are unusual things almost every day," Osweiler said the predominant diseases they see are pig respiratory diseases, bovine virus diarrhea and companion animal infectious diseases and biopsies. In the toxicology section, testing for lead poisoning in cattle and dogs is fairly common, he said.

"But about two-thirds of what we do is not for sick animals," Osweiler said. "It's simply testing blood samples from healthy animals to identify diseases the animal may have been exposed to or may be a carrier for. This is the preventive side of what we do."

This type of laboratory analysis is used primarily as a management tool for livestock herds, he said. It's also used extensively for export testing.

"Iowa sends a lot of livestock, horses and even some pets to other states and other countries that have different disease exposure rules that require proof of testing."


Aardvarks to zebras
And what about those unusual cases?

"If you look down our list, it practically starts with aardvark and ends with zebra. Although those are rare, we handle a wide variety of Iowa wildlife, exotic pets and even an occasional zoo animal, including a giraffe and an elephant," Osweiler said.

Several years ago, the VDL was asked to determine the cause of death of a Bengal tiger that died during a circus' visit to Des Moines.

"They brought the tiger up here for an autopsy and a diagnostic work-up. It wasn't anything contagious though," he said.

Sometimes, however, it's prudent to call in the federal diagnostic labs, such as the National Veterinary Services Laboratory in Ames.

"If we see a really unusual illness or a foreign animal disease -- a disease never seen in Iowa -- which could potentially require strict quarantine and follow-up investigations, we turn it over to the federal lab right away."

This spring, the VDL had such a case when a pathologist noticed an unusual problem in a rabbit.

"It was a viral disease, rabbit hemorraghic fever, which is classified as a foreign animal disease. The good thing is that the disease was caught, referred to federal authorities and was promptly under control. As far as I know, there hasn't been another occurrence since," Osweiler said. "Our job really is to help with any species and try to point toward whatever disease it may be."

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Revis ed 12/6/00