How come Jesus never mentioned that diseases are caused by viruses?

A few pre assumption here for the sake of discussion
1. God exists
2. God is all knowing
3. Jesus is God.
4. The Gospels Books are factual

After doing some research of my own, I have come to conclude that many of the so called demonic possession incidents in the New Testament especially in the Gospels, are actually sicknesses that we know of today. We have to understand that medical science in those days was practically non existant. People out of desperation seeked for divine aid in the hope that they could be healed of their suffering. In the Gospels books, it is repeatedly depicted that Jesus healed people by driving out demons from the afflicted. All manners of sicknesses are healed by expulsion of demons. In other words, demons are supposingly the cause of sicknesses. This is very strange judging from our current knowledge of sicknesses that they are caused by bacterias and viruses. Since Jesus (God) is all knowing, he could not have not known that diseases are caused by viruses. With this reasoning something is very wrong here. Why did the Gospels point out so blatantly that every sick people are posessed with demons? To make any sense here, we must really find a rational connection between demons and viruses, which is sadly impossible. And is it rational to say that doctor today cast out demons to heal sick people with medicines? How come people get healed without the doctor saying "Demon, depart from this patient!"?

I shall make a preposition here. People in those days did not know that diseases are caused by viruses. Without that knowledge, they have always believed that sicknesses are caused by demons! We can empathize with that belief easily because the Gospel books were written around 100-200 AD. Another important thing I need to point out is the number of people who still died even though they resorted to praying in those days. The 'Black Death' is an infamous example to illustrate this. It was also a period where most people believe in God for healing and deliverance. But just look at the number of people who had been wiped out by the plague. Where was God's miraculous healing? These people were in need of medicines and vaccinations, not exorcism!

With the development of medical science, people gradually turn to medical science rather than to divine sources for healing. The idea that diseases are caused by demons has absolutely no place in the field of science and in modern days.

To conclude, I am skeptical of the healing incidents in the Bible.

This is one of the prophecies for the Messiah, in Judaism. There will be no more illness. Obviously Jesus failed to fulfill this.

Either he was completely unaware of what causes illness and how to cure it, or he just didn't care enough to teach this knowledge to the people so they could save the lives of their fellow mankind. We would have no cancer, no flu, no any illnesses at all if Jesus had fulfilled this prophecy.

Epic fail there.

The Bible disproves your "THEORY" that viruses cause diseases. All diseases are caused by demon possession, as proven by the Bible. Stop talking about viruses, or God will use penicillin on your soul.

Creationists need have no fear of Swine Flu - it can't possibly evolve into something more virulent...

The supernatural always rules over the natural.

Germs amd viruses have come into being without his knowledge!

The goatherders who wrote the buy-bull had no knowledge of anything that small.

Sad in so many ways