Section 104. If a disease dangerous to the public health exists in a town, the selectmen and board of health shall use all possible care to prevent the spread of the infection and may give public notice of infected places by such means as in their judgment may be most effectual for the common safety. Whoever obstructs the selectmen, board of health or its agent in using such means, or whoever wilfully and without authority removes, obliterates, defaces or handles such public notices which have been posted, shall forfeit not less than ten nor more than one hundred dollars.