Gene-edited pig heart that was transplanted into an American patient this year was infected with porcine virus, which ultimately led to his death two months later.

David Bennett Sr was alraedy near his death when he received the heart transplant in January, which was hailed as a success intially as the first inter-species transplant.

According to Bartley Griffith of the University of Maryland School of Medicine, the transplant surgeon, the patient’s heart was performing like a “rock star” a few days after the surgery. Just 40 days later, Bennet was feeling worse and another month later he succumbed to the virus.

The MIT Technology Review learnt that the transplanted heart was infected with porcine cytomegalovirus, which is a preventable infection that can have “devastating” effects on transplants.

Specialists are now deliberating if the presence of the virus could be the cause of Bennet’s death. Griffith believes that the virus “could be the actor, that set this whole thing off.”

It seems that the experiment of xenotransplantation failed compromised due to unforced error since the pigs were supposed to be raised virus-free to be able to provide organs.

Griffith, however, believes that “if this was an infection, we can likely prevent it in the future.” Specialists could have more strict and elaborate procedures to screen organs for viruses before the transplant which could lead to a much longer life for the patient.

The human immune system remains the greatest obstacle that can ferociously fight to remove foreign cells from the body. Specialists have tried to avoid body rejection of the organ by engineering organs by removing and adding genes.

Similar studies have been conducted using transplants like pig organs on baboons and attaching pig kidneys to brain-dead people. Joachim Denner of the Institute of Virology at the Free University of Berlin who led the study of baboons considered it a “great success” but said the latent virus was hard to detect and that “if you test the animal better, it will not happen. The virus can be detected and easily removed from pig populations, but unfortunately, they didn’t use a good assay and didn’t detect the virus, and this was the reason. The donor pig was infected, and the virus was transmitted by the transplant.”

While researchers are still puzzling out the real reason behind Bennet’s death, Griffith states, “I personally suspect he developed a capillary leak in response to his inflammatory explosion, and that filled his heart with edema, the edema turned into fibrotic tissue, and he went into severe and un-reversing diastolic heart failure.”

The scientific community strongly believes the procedure was worth it since it helped them gain insights and set themselves right. Bennet’s son remarked that: “We also hope that what was learned from his surgery will benefit future patients and hopefully one day, end the organ shortage that costs so many lives each year”.