For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
It could be argued that all illness is of Satanic origin as sickness came into the world as a result of the fall of Adam and Eve. It is interesting that during Jesus' ministry on earth that many of the illnesses He healed were caused by evil spirits. Traditional western Christianity likes to overlook this aspect of Christ's ministry and doesn't even consider it a possibility in this age of enlightenment, but it's there.