The Xeno Solution

Someday soon:

The use of animal organs in human patients has revolutionized medicine in the 21st century, freeing thousand of patients from dialysis, and sparing them the slow death of waiting for a human organ that may never come. Thanks to the discoveries of Paradigm Transplant Solutions, reliable organs are available to almost anyone who needs one.

Some fear that animal transplants could cause a deadly virus to cross over into the human population, triggering an epidemic of catastrophic proportions. However, PTS uses only cloned animals that have been genetically-engineered to be virus-free, so this danger has been eliminated.

Or has it?