David Bennett Sr., 57, of Maryland, died in March, just two months after the groundbreaking experimental transplant. University of Maryland doctors said Thursday they found viral DNA inside the pig heart. They did not find signs that this bug, called “porcine cytomegalovirus,” was causing an active infection.
In this photo provided by the University of Maryland School of Medicine, members of the surgical team show the pig heart for transplant into patient David Bennett in Baltimore on Friday, Jan. 7, 2022. (Mark Teske/University of Maryland School of Medicine via AP, File)
The animal virus was first reported by MIT Technology Review, citing a scientific presentation from Dr. Bartley Griffith, the surgeon who performed Bennett’s transplant.
A major worry about animal-to-human transplants is the risk that it could introduce new kinds of infections to people. Griffith told The Associated Press that some viruses can be a “hitchhiker” because they lurk without causing diseases. Now, researchers are pursuing more tests to ensure they don’t miss these kinds of viruses.
Doctors have for decades tried using animal organs to save human lives without success. Bennett, who was dying and ineligible for a human heart transplant, underwent the last-ditch operation using a heart from a pig genetically modified to lower the risk that his immune system would rapidly reject such a foreign organ.
The Maryland team said the donor pig was healthy, had passed testing required by the Food and Drug Administration to check for infections, and was raised in a facility designed to prevent animals from spreading infections.
FILE: David Bennett Jr., right, stands next to his father’s hospital bed in Baltimore, Md., on Jan. 12, 2022, five days after doctors transplanted a pig heart into Bennett Sr., in a last-ditch effort to save his life. (University of Maryland School of Medicine via AP)
Griffith said his patient, while very ill, had been recovering fairly well from the transplant when one morning he woke up worse, with symptoms similar to an infection. Doctors ran tests to try to understand the cause, and gave Bennett a variety of antibiotics, antiviral medication and an immune-boosting treatment. But the pig heart became swollen, filled with fluid and eventually quit functioning.
“What was the virus doing, if anything, that might have caused the swelling in his heart?” Griffith asked. “Honestly we don’t know.”
Meanwhile, doctors at other medical centers around the country have been experimenting with animal organs in donated human bodies and are anxious to attempt formal studies in living patients soon.
The Associated Press contributed to this report.