Accumulations of rat feces can spread bacteria. Rats can also contaminate food sources and add to allergic reactions in humans. Once the fecal matter becomes dry, it can be very hazardous to breathe. Potentially spreading diseases such as Hantavirus, Bubonic Plague, Salmonellosis, Rat-Bite Fever. Therefore, sanitation and decontamination are an extremely important part of rat control after removing the rats and excluding them from the structure. Never sweep up dry droppings as this aerates the dust and makes it easier to breathe. If vacuuming, be sure to use a vacuum equipped with HEPA Filtration.