Doctor Guilt?

Brent admired the chimpanzee he sketched at the zoo. He regarded the animal as contemplative. He was unaware that similar animals in the wilds of Africa were the source of a virus that would lead to his death from AIDS. Brent became infected with HIV from the medicine he infused to treat his hemophilia.
At six months of age, his parents were alarmed when they discovered bruises on his chest which led to the discovery of hemophilia. From that moment forward, he received frequent intravenous infusions of concentrate to treat recurrent bleeding episodes. Infusions of the medicine relieved pain and suffering from bleeding. His life seemed normal. Unexpectedly, Brent's life changed after the discovery of HIV contamination of the medicine.
The medicine was manufactured from the plasma of paid blood donors. Unbeknownst to Brent, the plasma was polluted with HIV. The SIV in chimpanzees changed to become HIV in humans. But the chimpanzees were not the cause of the transfer of SIV in animals to HIV in humans. The change from SIV in animals to HIV in humans was the result of human activity. The change came about with the production of the hepatitis B vaccine.
Who was responsible for the pollution of the hemophilia medicine with HIV and hepatitis viruses? Was Brent's death preventable?