A month after the transplant, a man in the US who had a pig heart transplanted is doing well under the circumstances.

The 57-year-old David Bennett is alive and well, a spokeswoman for the University of Maryland said on Sunday morning at the request of the German Press Agency.

Bennett had a pig's heart implanted on January 7th.

"The long survival time of one month is a huge success for xenotransplantation, especially when you consider that the first human-to-human heart transplantation in Germany lasted less than 24 hours," explained Joachim Denner, transplantation expert from Freie Universität Berlin.

The transfer of animal organs to humans is called xenotransplantation.

Bennett requires 24-hour surveillance at the clinic.

The greatest danger to his life is that the body will reject it, says expert Denner.

“The immune system needs a certain amount of time before it builds up an immune response.

The antibodies and immune cells that would be able to reject the organ are only being formed at the moment.