Leviticus 15:2 Speak unto the children of Israel, and say unto them, When any man hath a running issue out of his flesh, because of his issue he is unclean.
Long before science was explaining things God’s people were obeying Him and doing the right thing. The Jews were taught to cleanse themselves and to stay away from impurity. This stopped the spread of disease.
Every time I hold the Bible in my hands I am in awe at how good our God is to give us His Word. His Word is so far beyond what any man could ever have imagined or done.
Read it and learn. Realize that God is speaking because no man could have been that smart and so much ahead of his time!