Diseases may be caused by rodents when they enter properties, especially during the cool season from November to March. Because, like any other organism, they need food, water, and shelter to survive. Rodents get into properties through open and broken doors and windows; holes around pipes; and even the smallest cracks and crevices. After entering buildings, they can cause serious health and property concerns. In this article, we try to deal with health concerns associated with rodents, disease-causing agents, symptoms, and sickness from rat droppings in Greater Vancouver and other parts of the world.