The genetically modified pig heart given to a terminal Maryland patient in January was infected with a porcine virus that may have been the cause of his death nearly two months later.

David Bennett, 57, died in March after making history by receiving the first-of-its-kind pig heart transplant, a procedure that signaled hope to several patients amid a shortage of donated organs. Officials began an investigation into the cause of his death, with doctors at the University of Maryland School of Medicine announcing in April that the presence of the pig virus may have derailed Bennett’s progress and led to his death.

“We are beginning to learn why he passed on,” said Bartley Griffith, the transplant surgeon, during a webinar discussing the groundbreaking procedure. “[The virus] maybe was the actor, or could be the actor, that set this whole thing off.”


In fact, the detection of the pig virus may actually be good news for doctors who want to perform more pig heart transplants, he said. If the virus caused a premature death for Bennett, patients who receive virus-free hearts could theoretically live much longer. More thorough testing of the animals’ tissues could help detect the virus early on and be removed from pig populations.

“If this was an infection, we can likely prevent it in the future,” Griffith said.

However, some doctors stressed that Bennett’s deteriorating condition could have also played a role in his death.

“This patient was very, very, very ill. Do not forget that,” Joachim Denner of the Institute of Virology at the Free University of Berlin told Technology Review. “Maybe the virus contributed, but it was not the sole reason.”

Bennett, who was diagnosed with terminal heart disease, received the transplant in January as a last-ditch effort to survive because he did not qualify for a conventional heart transplant. The procedure gained widespread attention, and previous attempts resulted in deaths when patients’ bodies rejected the animal organs.

The Maryland resident was informed of the risks of the surgery, and the Food and Drug Administration gave surgeons the green light to go through with the procedure on Dec. 31, 2021. He received the transplant on Jan. 7, with surgeons reporting Bennett was in good condition just days later.


However, when his condition began to deteriorate in early March, doctors placed him on palliative care. The hospital said he could communicate with his family in the hours before he died.

More than 100,000 people are on the national transplant waiting list, and more than 6,000 people die annually before receiving one, according to the Organ Procurement and Transplantation Network.