'It takes a toll': researchers struggle with lockdown cull of lab mice

Xiao-Tong Su, a postdoctoral fellow researching hypertension at Oregon Health and Science University (OHSU) apologizes to mice when she euthanizes them. “I try to think that they’re sacrificed for human health and for science,” she told me over the phone. As the owner of two pet rabbits, she had to switch to working with mice early in her career after repeatedly becoming too attached to rabbits she worked with.

In the world of medical research, mouse and rat euthanasia are par for the course. Once an experiment is complete, mice are typically rendered extraneous since they can no longer be used as a control, and are humanely euthanized. Most universities abide by a reductionist policy, using as few mice as possible – so whenever possible, one mouse can be used for more than one study. Depending on their work, grad students and postdocs will euthanize one animal per day. “It never gets easier,” Sayra Garcia, a second-year PhD student at the Albert Einstein College of Medicine, said.

Starting in March, institutions across the country were suddenly forced to halt most non-Covid-19-related research, which was deemed non-essential, and close labs. And as researchers, lab managers and animal care technicians prepared to work from home, resources to support mouse colonies dwindled. As a result, lab directors at various colleges, universities and medical schools received orders from provosts to swiftly reduce mouse populations. “What that led to was a high volume of activity in one week in terms of euthanasia,” Eric Hutchinson,director of research animal resources at Johns Hopkins, told me from his recently – reopened lab. “We knew it was going to get both physically and emotionally overwhelming.”

Usually animal care technicians, who are trained veterinarians responsible for animal maintenance, perform the majority of euthanasia. The procedure is done with carbon dioxide, followed by surgical dislocation of the neck to confirm death. Early on in the pandemic, however, animal care technicians were scrambling to prepare for closures, leaving lab managers with the burden of culling their own colonies. That meant, in many labs, just one person was responsible for euthanizing hundreds of mice, often in one sitting.

“Sometimes they’ll jump around and try to get out of the cage,” one lab manager, who preferred to remain anonymous, said of witnessing final panicked moments. But the part he disliked the most, he went on, is the surgical dislocation. “They’re in there, they’re dead, but it’s part of the protocol. You just grab their neck and tail …” he trails off. He emphasized often that it had to be done, that he took care of things and didn’t think about it too much. But also, he told me it was hard. “I really don’t like doing it, so doing it 150 times definitely affected me.”

Tracy Gluckman, associate director of comparative medicine at OHSU, declined to be interviewed, opting instead to send a paper she co-authored on “compassion fatigue”, which was first published in Laboratory Animal Science Professional. The condition, first identified in nurses, can arise after routinely witnessing individuals in pain. Only very recently, however, has the diagnosis been associated with the laboratory animal science community. “We may regularly witness or induce disease in healthy animals, observe morbidity and mortality in the animals we care for, and at times, euthanize animals for reasons other than alleviating pain or distress,” the paper reads.

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Compassion fatigue manifests in a similar way to post-traumatic stress disorder. And considering the unprecedented mouse culling necessitated as labs shut down, universities and individuals have had to be acutely aware of their staff’s emotional needs.

Even for animal coordinators like Hutchinson, who facilitate the care of thousands of animals instead of studying a single colony, which affords him a level of detachment, this sudden bout of euthanasia was difficult. “I did several shifts down there,” Hutchinson said, referring to the animal care facilities, “and it takes a toll.” He, among others, emphasized the importance of a tight-knit community. “We were really trying to be vigilant to make sure people didn’t go beyond their own limits.”

Garcia similarly spoke of the importance of support and solidarity, even in routine euthanasia. “I find that if my lab mate’s having a hard day, I euthanize her mice for her. We kind of switch off handling.”

But her concerns aren’t solely surrounding the wellbeing of her colleagues or the colonies they care for – Garcia is also uncertain about the state of her research. Because of the hiatus she will have to rebuild some of her colonies, delaying her studies. “I’m kind of like, oh I’m never going to graduate because my progress is determined by my animal models. It’s super anxiety-inducing.”

For graduate students and postdocs, scrapping months or years of work can be devastating. One lab head expressed her concern for students across the US, explaining that postdocs who are leaving their labs this year will have an extremely hard time getting a job, either in academia or industry. “Once you’re out of the workforce for a few months it’s really hard to get back in.”

In academia, the typical road to employment follows a formulaic path: finish study, publish paper, apply for training grant based on said paper, pursue faculty jobs. Training grants and papers work as essential credentials for the hiring universities. Losing months of lab time on an expiring grant could result in a huge career setback.

The impact the culling has also crippled critical, non-Covid research. “I see a lot of important infectious diseases, like bacterial pneumonia and tuberculosis for which we either don’t have cures or are in danger of having so much antibody resistance,” said another researcher whose lab is currently functioning at 20% capacity. Losing 75% of their mouse population means that her lab is now performing experiments using cell cultures while they wait for breeders to repopulate the colony. This could result in a six-month to year-long delay in crucial treatments.

Related: Scientists split as genetics lab scales down animal tests

Karen L Bales, who uses lab animals in her research of autism and schizophrenia, told The Chronicle of Higher Education that, as a result of lab closures and animal culling, American Biomedical research could suffer a two-year handicap.

And then, as if the scientific and psychological ramifications weren’t damning enough, Peta, publicly and loudly, voiced concerns about the Covid-related mass culling. I contacted numerous researchers who elected to withhold their commentary, fearing legal repercussions from the animal rights group. Others chose to remain anonymous after bouts with internet trolls who had been emboldened by Peta’s stance. And many researchers who tweeted about the culling in March have removed those tweets. These public judgments can work to exacerbate the ethical qualms associated with animal research, leading, in the worst cases, to compassion fatigue. “You’re kind of damned if you do, damned if you don’t, because animal work does produce extraordinary results,” Garcia urges. “But working with mice – it’s morally exhausting.”

Now, some labs are reopening, though recent spikes in infection rates threaten to close them again. Most are functioning at a limited capacity as they attempt to rebuild colonies and resume experiments. But, as researchers submit animal orders and ramp up breeding, grants are running out and time in the lab is restricted. Despite it all, researchers remain hopeful in the absence of certainty. I asked Garcia about her next steps on the road to graduation. “Well,” she said, shrugging her shoulders through the computer screen, “I guess I’ll cross my fingers.”