It may be years away, but the day is coming when a person needing organ transplant could receive that organ from a pig.

Hank Harris, professor of microbiology, is researching how pig organs could be used for human transplants. Using animal organs in transplants is known as xenotransplantation.

There are advantages and disadvantages to using pig organs in humans, he said.

Harris said pig organs are very similar in size to human organs.

“Physiologically, [the organs] do the same process,” he said.

A pig’s liver will detoxify alcohol just like a human liver, Harris said.

He said pig organs are less likely to transmit diseases to human organ recipients than more closely related animals such as monkeys.

Eileen Thacker, associate professor of veterinary microbiology and preventive medicine, said studies have shown pig viruses placed into human cells in cultures have not infected human cells.

Thacker said humans more easily accept killing pigs for their organs because pigs have bigger litters than monkeys and pigs are among those animals killed for their meat on a daily basis.

The main disadvantage to using pig organs is that they contain a compound for which humans produce antibodies, Harris said. This would cause the body to reject the new organ, he said. Organ rejection is always possible and remains a concern when a human organs are transplanted to humans.

Scientists are researching “knock-out pigs,” or pigs that wouldn’t have these genes, Harris said.

Researchers are looking for a way to keep the pigs germ-free, but Harris said it’s impossible to keep them germ-free through the time of transplant.

A pig organ placed into a human body will cause an immediate rejection like any other organ transplant, Harris said.

Thacker said there is a concern that a transplant recipient will have a suppressed immune system and therefore be more susceptible to infection. That infection would likely come from another human rather than the organ.

James Roth, distinguished professor of veterinary microbiology and preventive medicine, said the FDA has to approve this before it will be used.

“[The FDA] has stringent rules to make sure there are no infectious diseases,” he said.

Roth said about 200 known diseases can affect pigs. Some of these diseases can be transferred to humans just by contact with the pig.

“It’s not very common to catch a disease from a pig in the USA,” Roth said.

Harris said the FDA is working on a process to approve the use of pig organs but it will be five to 10 years before it gets approved.

Thacker said she thinks using pig organs would eventually be a “good idea down the line.”