It shall be unlawful for any person suffering with an infectious venereal disease to perform any act which exposes another person to infection with said disease, or knowingly to infect or expose another person to infection with such disease; and no physician, health officer or other person shall give any certificate showing a person to be free from a venereal disease, but such certificate shall simply state the results of tests and examinations that may have been made, and what tests were made to arrive at the results stated.