Faced with her lab’s imminent closure, Sunny Shin had already begun to fear she would have to euthanize large numbers of the mice she works on. Then, last Tuesday, the email came from her school’s vice provost of research. “In response to the public health crisis caused by COVID-19,” it read, “mouse/rodent users should cull their colonies as much as possible.”
Shin, a microbial immunologist at the University of Pennsylvania Perelman School of Medicine, had to deliver the bad news to her lab manager: Euthanize 200 mice—more than three-quarters of their research animals—as quickly as possible. Many of the rodents had come from Europe and Asia, and it had taken years to obtain them and breed them for the genotypes the lab needs to study how the immune system responds to bacterial invaders. “It was heartbreaking,” Shin says, “scientifically and emotionally.”
Shin’s lab isn’t alone. Last week, confronting the possibility of extreme animal care shortages and disruptions to research, universities across the country asked labs to think hard about the mice they actually need, to freeze the embryos of valuable or unique strains, and—in many cases—to cull the rest.