Illness is a state of body, and also a state of the mind. There is a linkage. A strong mind handles illness with patience. A weak mind is engulfed with fear, and panic.
There are times when the evil in the mind causes illness. Thoughts physically originate in the brain but their effects are felt in the body. Negative people even when they are perfectly well, do not feel fully mentally well. Their negativity does not allow a peaceful feeling. They have fears to deal with. They have the negative vibes they have sent to people around to deal with. Negativity eats into your state of physical well-being. You often start feeling, "I am ill".
An illness is the action of our negative karma. It comes back to us. When we hurt someone, do injustice to someone, or be indifferent and don't help, some and all of these factors add upto the debit balance in our karmic justice. Justice has to be done to us. To blot out that negative balance, we fall physically ill and suffer pain, and discomfort. So, an illness is nature's way of balancing. Don't blame anyone for your illness. It is your karma alone which has caused it. Instead be grateful that the superpower has chosen to blot some of the minus balance in your account through this illness. Say to yourself, "I am grateful that I am ill".