From hummingbirds to bears, there is often something interesting (and a bit gory) on the steel tables in the necropsy laboratory.
Stacie Nellor handed a stainless steel bowl up to the first person in the front row of the viewing gallery. In the bowl was a feline abdomen that contained a large tumor. The specimen was passed among a group of two dozen students while Nellor explained the source of the cat’s abdominal bleeding: a rare disease called Factor XI Deficiency.
Nellor is a fourth-year veterinary student working in the necropsy lab where, among other things, she performs animal autopsies (called necropsies) under the supervision of a pathologist. Nellor saved the cat’s remains to present at the Wednesday morning necropsy rounds. The rounds are open to any student or staff of the Carlson College of Veterinary Medicine, and sometimes visitors on guided tours attend as well.
The necropsy lab is one of the busiest services at the Oregon Veterinary Diagnostic Laboratory (OVDL). In addition to educating students, pathologists perform necropsies for veterinarians, pet owners, and farmers, and work closely with many government agencies from Oregon Public Health to the U.S. Department of Agriculture.
Dr. Rob Bildfell is an OSU professor, a board-certified pathologist, and supervisor of the necropsy service. In his twenty years at the lab, he has seen a wide range of interesting cases involving many different species, and a lot of those came from the Oregon Department of Fish and Wildlife (ODFW).
From big bears to tiny hummingbirds, ODFW is interested in knowing why animals have died. “Typically they send us species that are of interest to their clientele, like deer, elk, and ducks,” says Bildfell. “Or they may be concerned about disease transmission when an animal has had contact with humans, like a wild rabbit that a Good Samaritan has tried to help.”
The necropsy service also helps ODFW investigate when a large number of one species has died. “When there is an unanticipated die-off, they bring them to us for necropsy,” says Bildfell. “For example, nearly every summer there is a die-off of ducks in the Portland area and we help investigate that.” The cause of the die-off is usually botulism, a bacteria over-growth caused by algae blooms in water.
With a long-standing controversy over management of wolves in Oregon, the Department of Fish and Wildlife’s enforcement branch investigates their cause of death whenever possible. “Some wolves simply die from a viral infection,” says Bildfell, “but we have had a few that were poisoned or shot.” In those cases, the OVDL gathers forensic information. “We order radiographs or CT scans to identify where bullet fragments are located so we can recover them.”
The OVDL also gathers forensic information when the Oregon Humane Society is investigating animal abuse cases. Often that evidence is sent to police agencies for criminal investigation.
When a large animal dies at the Portland Zoo or Wildlife Safari, the OVDL is the go-to lab for necropsy to establish cause of death. Last fall, Assistant Professor Dr. Duncan Russell travelled to Portland with three pathology residents to find out what happened to Lily, the beloved elephant calf that died in November. “The zoo had a likely pre-death diagnosis of herpes virus. We were able to confirm that,” says Russell.
The Oregon Marine Mammal Stranding Network is a group of volunteers who respond to marine mammals stuck on Oregon beaches. When the mammals they find are dead, they rely on the OVDL to diagnose the cause. Sometimes the network volunteers do their own field necropsy and then send samples to the OVDL, and sometimes they transport the whole animal to Corvallis. “Typically these are sea lions, harbor seals, and an occasional porpoise or dolphin,” says Bildfell. “On occasion, we are also asked to examine mortalities from the Oregon Coast Aquarium, as part of their health monitoring system.”
Animals arrive at the OVDL by various methods: flatbed truck, horse trailer, the back of a van, or even the trunk of a car. When they pull up to the loading dock at Magruder Hall, they are carried inside via a hoist and rail system that takes them into a walk-in cooler where they are stored until the team can perform a necropsy. Small animals like cats, gerbils and songbirds are stored in a standard, household freezer. “People bring pets to be necropsied because they want to know what happened,” says Bildfell. “They are concerned that their other animals may be at risk.”
The OVDL building is forty years old and showing its age, but remodeling the existing necropsy spaces is not a great solution. “We need a new facility,” says Bildfell. “Our space is inadequate for all the different services we provide, and it would be better to have it separate from Magruder Hall to maximize biosafety.” Bildfell would like any new building to include a better way to dispose of carcasses.
What does the OVDL do with all those animal remains? “When I started here many years ago, there were several rendering businesses [in the valley] that would come pick up animal remains and actually pay us. That industry has collapsed; there is only one rendering business now, and they limit the types of material they will take. And we have to pay them,” says Bildfell. “We also pay to use the incinerator on campus, and preparing the remains for that is labor intensive.” A better solution would be for the OVDL to install a chemical digestion system.
On a larger scale, OVDL Director Dr. Mark Ackerman sees a statewide need for better carcass disposal. “If diseases like African Swine Fever or Chronic Wasting Disease spread into Oregon, they could create high mortality. Currently, the state does not have adequate capacity for carcass disposal in the event of a large disease outbreak,” says Ackerman.