Human history has been strewn with the visitation of plagues.  In pre-science times the sources of these were unknown, so various explanations were offered, some of which blamed God, or the sins of the people, for these evils.  Humans did not know then that they could come from contaminated water, animals, insects, all bearing bacteria and viruses that they could not see in the absence of a microscope.  The world is a fallen place where disease can visit us, sometimes in huge ways.  Healers have used their scientific knowledge to stop these things and have often prayed for the Creator God to show them a way to do it; the stories of these triumphs are often truly amazing.  The general health of the world is better for it; though not all have access to the healing sciences.  Healing was a ministry of Jesus.  Be like Him, be a healer.  Know that the day is coming when all disease will be banished from the new heaven and the new earth. 

“And I saw the holy city, new Jerusalem, coming down out of heaven from God, prepared as a bride adorned for her husband. And I heard a loud voice from the throne saying, “Behold, the dwelling place of God is with man. He will dwell with them, and they will be his people, and God himself will be with them as their God. He will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning, nor crying, nor pain anymore, for the former things have passed away.” (Revelation 21:2–4 ESV).