Is there an underlying spiritual issue when it comes to disease in general and contagions in particular?
No, we’re not speaking about the reports of spiritual phenomena during the famous Justinian and Black Death plagues. We’ve already covered that. Nor about the 1918-1920 flu pandemic, about which we have likewise written through the years.
We’re speaking about personal wellness and spirituality — knowing, as we also have discussed before, that Christ Himself, in casting out demons while healing people, showed there is often not just an underlying spiritual component but an over-riding one.
This came to mind in leafing through Deadly Feasts: Tracking the Secrets of a Terrifying New Plague, by Pulitzer-Prize-winner Richard Rhodes. It’s about a different affliction — prion brain diseases (such as “mad cow”) — and notes that:
In June 1913, a maid in a convent in Breslau, Germany, named Bertha Elschker suffered a breakdown and was taken to a clinic at the University of Breslau, which was directed by the very neurologist, Alois Alzheimer, who gave his name to the eponymous brain disorder.
And perhaps it’s all it was: physiological. There are mental disorders that are biological and biochemical, as well as psychological, in nature. Perhaps solely (though spiritual factors by and large hold some sort of sway).
As far as plagues, Church leaders throughout history blamed evil for them, and classical artists often depicted demons as hovering above the infirm.
Just classical artwork? Simple metaphor? During the Black Death, strange lights and dark animals were exorcised by local clergy (including bishops).
The question is whether physiological factors can meld with spiritual ones, in sort of a perfect storm: one exacerbating the other, especially with diseases cited in Jesus’s healing-deliverances such a epilepsy, specifically.
“Her normally cheerful personality had changed abruptly about a month before,” noted Rhodes. She no longer wanted to eat or bathe. “Three days before [a physician named Hans Gerhard Creutzfeldt] saw her, ‘she suddenly screamed out that her sister was dead, that she was to blame, that she was possessed of the devil, that she herself was dead, that she wanted to sacrifice herself.”
Her dazed looks, silly 
giggling, twitching eyes, and unsteady walk made it obvious to Creutzfeldt that she had brain damage.
And so she did: after she died, an autopsy revealed that something had killed millions of brain cells, a microscopic agent known as a “prion.” Did evil move in through that injury, that weakness, to do what she claimed — possess her — or perhaps even abet in the damage to begin with?
She had fluttering facial muscle, ticlike jerks, and tremors. She went into stupors and then suffered one epileptic attack after another. This is also what has been noted in outbreaks such as one in LeRoy, New York, some years back, in 2012, during which first one girl then another and another and soon eighteen in a single school exhibited the same strange noises, laughing, and strange movements. The cause remains a mystery.
Perhaps sheer biology. That’s certainly possible. A virus or bacteria can make us sick with no help from a demonic influence. This is a fallen world, with physical as well as spiritual pitfalls.
But it is always good to command out evil (in Jesus’s Name) whenever there is sickness, in case and in the event the devil, in his exquisitely cruel mischief, is making things worse or as the father of death (and deception) is the chief orchestrator.
[resources: healing books]
[Footnote from Luke 9: 37-43: “Then on the following day, as they came down the hillside, a great crowd met him. Suddenly a man from the crowd shouted out, “Master, please come and look at my son! He’s my only child, and without any warning some spirit gets hold of him and he calls out suddenly. Then it convulses him until he foams at the mouth, and only after a fearful struggle does it go away and leave him bruised all over. I begged your disciples to get rid of it, but they couldn’t.”
“You really are an unbelieving and difficult people,” replied Jesus. “How long must I be with you, how long must I put up with you? Bring him here to me.”
“But even while the boy was on his way, the spirit hurled him to the ground in a dreadful convulsion. Then Jesus reprimanded the evil spirit, healed the lad and handed him back to his father. And everybody present was amazed at this demonstration of the power of God.”]