Approximately 20% to 30% of these people develop chronic liver disease, and many require liver transplantation.

BBC: Better treatment for Hepatitis C

And it added in one case, a woman using black cohosh needed a liver transplantation after a particularly severe reaction.

BBC: Some women are using alternative therapies instead of HRT

But the inventors in Oxford and the transplant team in London stress it is too early to draw any firm conclusions as to the benefits of 'warm liver' transplantation.

BBC: 'Warmed liver' transplant first

However, no rabies test was done before the before the donor's kidneys, heart and liver were delivered for transplantation in September 2011, the CDC said.

CNN: CDC: Man died of rabies from kidney transplant

Two injection sites were used: the surface of the small intestine and the hepatic portal vein that connects the pancreas and the liver, where islet transplantation normally is performed.

WSJ: Cow's Milk Blamed for Too Many Infant Allergies

At the time, rabies wasn't suspected as the cause of the donor's death, and no rabies test was done before the donor's kidneys, heart and liver were delivered for transplantation in September 2011, the CDC said.

CNN: CDC: Man died of rabies from kidney transplant

In such cases, the pig liver is used as a bridge to transplantation, buying the patient time until a human liver can be found.

CNN: Researchers clone pigs