No dog shall be kept in the City during an official State, County or City quarantine period on dogs provided, that the owner or custodian of any dog may keep and maintain such dog on his own premises, properly enclosed, during such quarantine period and provided further, that the owner or custodian of any dog shall be permitted to take such dog off of its own premises onto the public streets, sidewalks and public places in the City during such quarantine period, provided such dog is accompanied by a person over the age of fifteen years and provided the dog is on a leash and muzzled while off of the premises of the owner or custodian, during such quarantine period.