If the director receives information of the existence of any contagious, infectious, or transmissible disease which affects domestic animals within this state, he shall thoroughly investigate it. In making such an investigation, he may enter any premises and inspect any animal.

This chapter does not deprive the regular inspectors who are employed by any chartered or incorporated city, or city and county, after they have passed a civil service meat, market, and poultry inspection examination, of the powers which are granted them by such city, or city and county, to inspect animals.