Dog bites are categorized by the World Health Organization (WHO) into three categories based on the level of exposure to saliva and skin integrity, determining the risk of rabies and the need for post-exposure prophylaxis (PEP). Category I involves touching or feeding an animal with no skin damage, Category II includes minor scratches or nibbles without bleeding, and Category III involves single or multiple deep bites, scratches, or licks contaminating mucous membranes or broken skin.