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May 15, 2020

Research delayed, rodent populations reduced during pandemic

Universities try to reduce risk to humans, maintain animal welfare as studies halted
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Updated May 1, 2020

Universities delayed new studies this spring to reduce contact among people, including researchers and animal caregivers.

Those delays often involved reducing breeding of research animals and sometimes depopulating mice. Even after campuses reopen, rebuilding many of these populations could take months.

Laura J. Knoll, PhD, professor of medical microbiology and immunology at the University of Wisconsin-Madison School of Medicine and Public Health, said university officials strongly encouraged that investigators reduce their populations of easily replaceable animals because the university would be short staffed. She had about 700 mice prior to the pandemic, and she estimated two-thirds were euthanized.

Yerkes employee wearing PPE interacts with research monkeys
An employee of Yerkes National Primate Research Center at Emory University wears personal protective equipment while working near monkeys. The institution houses about 3,300 nonhuman primates. (Photos courtesy of Emory University) 

“They want us to get the numbers down as much as possible in the facilities,” Dr. Knoll said. “They are working with limited animal care staff.”

She said reducing the human health risk was the right decision, rather than maintaining large populations of mice.

Dr. Knoll studies Toxoplasma gondii, and her team recently identified why cats are the only natural hosts for a phase of T gondii’s life cycle. She used that knowledge to induce that phase in mice.

The university was maintaining mice from rare or expensive breeding lines, she said. If researchers can return to campus this summer, she said, breeding and buying replacement mice likely would delay any experiments until late fall.

Dr. Janet Welter, chief campus veterinarian at the University of Wisconsin-Madison, said the university had suggested that principal investigators stop breeding mice and rats that they could buy from vendors. No universitywide policy required depopulating research animals, but she said individual units may have issued other instructions.

Dr. Welter said long-term projects continue, including a study started more than 20 years ago on aging in primates. And some current research includes COVID-19 transmission and vaccine studies.

“I am so impressed by the response this university has had to this unprecedented pandemic that we are dealing with,” Dr. Welter said.

Cornell University announced March 15 it suspended noncritical research. In a publicly available letter, Provost Michael Kotlikoff and Vice Provost for Research Emmanuel Giannelis wrote to campus colleagues that Cornell would reduce laboratory research and other nonessential research activities by March 18.

“Research that is essential for the understanding and reduction of COVID-19 risk should continue,” the letter states. “Beyond this, we ask that only those research activities that are absolutely necessary to retain critical research assets for long-term progress are conducted on campus.”

Cornell spokeswoman Melissa Osgood said about 10% of the university’s rodent population was euthanized, which will slow current studies and delay future ones.

The Congressional Research Service published a report April 10 on the pandemic’s interruptions to federal research and development—which includes research by federal employees and outside research funded by federal agencies—and to conferences where scientists share knowledge. The report notes that, even among ongoing research projects, the altered schedules, increased distances between employees, and extra time spent on emergency planning reduced efficiency, if not also quality.

Protecting people and animals

Dr. Joyce Cohen is associate director of animal resources at the Yerkes National Primate Research Center and associate professor in the Emory University School of Medicine Division of Psychiatry and Behavioral Sciences. Her center stocked up on food, bedding, and other supplies for the animals, as well as focused on animal welfare and care as employees adapted to the pandemic.

Dr. Cohen’s institution has about 3,300 nonhuman primates and about 5,000 rodents. The center split staffing so half of animal care and veterinary employees work each day, reducing the overall risk that teams will become sick and require isolation. She also adjusted husbandry schedules, for example, to reduce how often the staff sanitize cages, but she noted daily cage cleaning continues.

Yerkes employee wearing PPE interacts with research rodents
The Emory University School of Medicine Division of Animal Resources maintains about 85,000 research animals, mostly mice.

The risk of COVID-19 infection in primates also is a concern, Dr. Cohen said, citing preliminary evidence that rhesus macaques inoculated with the virus can become infected. Staff members wear personal protective equipment while working with nonhuman primates and watch for respiratory illness.

“We’re putting together a colony screening program to start doing some antibody testing to look for any signs of infection in the colony,” she said. “We’ve already started screening animals that will be utilized on COVID-19 research.”

Dr. Douglas K. Taylor is senior veterinarian in the Emory University School of Medicine Division of Animal Resources and a professor of pathology and laboratory medicine. He said Emory’s main campus keeps about 85,000 research animals, mostly mice. That figure does not include the rodents at the primate research center.

Emory followed guidance from the Centers for Disease Control and Prevention on social distancing and personal protection, instituting rotating schedules and telecommuting, he said. Along with those measures, the university also directed investigators to consider which studies were time sensitive, critical, ongoing, or able to be delayed.

Dr. Taylor has seen a 10-15% drop in the institution’s animal census since the pandemic began, mostly in the mouse population. He attributed the decline to a combination of euthanasia at the conclusion of experiments, preparations for worst-case scenarios that include short staffing, and conservation of resources by limiting breeding and suspending intake of new animals.

Dr. Taylor said animal welfare considerations have been second only to human safety concerns.

Dr. Nina Woodford, attending veterinarian for Washington State University and director of the Office of the Campus Veterinarian, said research slowed as the institution told staff members to stay home or come in for reduced hours.

WSU delayed starting any studies that require long-term monitoring or extensive time in close contact with others in a laboratory, Dr. Woodford said. Some of the drug dependency studies, for example, involve conditioning animals, performing memory tests, and working closely with people and animals, she said.

“While we are finishing any ongoing studies, we’re taking a pause at starting any new ones of that nature,” she said.

The university also slowed breeding of research rodents and fish, and the rodent population has declined 15% as studies concluded and breeding halted, she said. WSU also had some teaching laboratory–use livestock that were sent to market ahead of schedule, she said.

“We have asked our researchers to identify what we call ‘priority save’ animals in the event that we would have to do more culling,” she said.

That would occur if too few people were available to feed and care for all of the animals, she said.

Once people are able to return to the university, Dr. Woodford thinks resuming many studies would require months. But studies using commercially available mouse strains would resume more quickly.

Robert Taft, PhD, is director of reproductive technologies and business development at The Jackson Laboratory, a nonprofit institution that breeds mice for use in research. Dr. Taft said JAX remains open and continues selling all of its genetic lines of mice. The types of mice ordered shifted, though, toward mice modified to express human-type cell receptors that allow infection with COVID-19.

He also saw a surge of requests to cryopreserve genetic lines. The institution is planning for a possible surge in demand as studies resume, and JAX can build colonies ahead as investigators share their plans. The institution also continues providing services such as testing half-lives of antibodies and characterizing mouse models through assays.

Disaster plans include pandemics

Tracy Parker, president of the American Association for Laboratory Animal Science, said federal regulators require that all facilities conducting animal research have disaster plans, and many of those plans have included pandemic response scenarios since an outbreak of severe acute respiratory syndrome. AALAS forums provided anecdotes on how facilities have executed those plans, with some continuing operations through teams providing daily care for animals. Some facilities donated PPE and other supplies to local hospitals, and some offered to aid studies on potential antiviral treatments, Parker said.

Dr. Jennifer K. Pullium, senior director of the Division of Comparative Medicine at the New York University School of Medicine, wrote in correspondence published in March in Nature that the COVID-19 pandemic could create shortages in staffing and supply chains in research institutions.

“As someone who helped labs to retool after Hurricane Sandy hit in 2012, I advise research groups to build up substantial reserves of crucial animal-care and laboratory supplies,” she wrote. “These include personal protective equipment as well as food, water and bedding for the animals.

“Individually ventilated cages can be brought in to cut back on cage-cleaning requirements. Back-up for services such as animal care and health checks will be necessary.”

In an interview with JAVMA News, Dr. Pullium said NYU investigators canceled some short-term experiments and ended others quickly. But the university maintained staff to care for remaining rodents.

“There are animal experiments that are specifically related to COVID-19,” she said. “Those are going full steam ahead, as you can imagine.”

NYU also increased use of cryopreservation following Hurricane Sandy, and it’s now used to save most unique rodent lines, Dr. Pullium said. Other lines are maintained in breeding colonies.

In disasters and routine days alike, institution leaders need to focus on their people, Dr. Pullium said. They need workforces that are resilient through their passion for their work, ability to adapt to change, and empowerment to make decisions.

Administrators need to consider these needs ahead of disasters, when they won’t have time, she said.

Correction: An earlier version of this article misspelled Dr. Jennifer K. Pullium’s name.