Norway Rats (Rattus norvegicus, also known as brown rats, sewer rats, wharf rats, or water rats) are notorious public health pests. Their infamy dates back at least to the 14th Century A.D., when plague carried by fleas carried by rats killed perhaps as many as one out of four members of the world's then-known population. But awareness of the connection between rats and disease may go back a lot further than that.

In the Old Testament book of 1 Samuel, the Philistines were afflicted with "tumors" and their land infested with rats after they captured the Ark of the Covenant. The "tumors" could very well have been the bubos associated with bubonic plague, which is transmitted by rat fleas. As a sacrifice to the God of Israel, the Philistines returned the Ark along with a sacrifice of five gold "tumors" and five gold rats, indicating some awareness of the relationship between the rats and the disease. (1 Sam. 5,6)

In addition to plague, rats have also been implicated in the transmission of salmonella, Lyme disease, and typhus, making rats one of the deadliest disease vectors in the natural world.

In addition to carrying diseases, rats also contaminate our surroundings with their urine, feces, and parasites; cause untold damage and fires through their gnawing; and can inflict painful, disabling bites with their razor-sharp teeth.

Mice and Human Health

Mice are also important public health pests. They are known to be involved in the transmission of several serious diseases including food poisoning, hantavirus, leptospirosis, Lyme disease, and typhus. They also contaminate many tons food and feed every year with their shed fur, parasites, urine, and feces.

Because of their small size and timidity, many times we first become aware that we have a mouse problem when we see evidence of their presence, rather than the mice themselves. Signs that you have a mouse problem include droppings, nesting materials, gnaw marks on wood, cables, or food packaging, footprints, or tail prints.