When it comes to pests and the diseases they can carry, rats pose some of the greatest threats to human health. The roof rat and the Norway rat both are culprits in the spread of deadly diseases.
The roof rat, known also as the black rat, is thought to be the carrier of the Black Plague, the deadly scourge that killed 30 to 60% of Europe's population in the Middle Ages. The Black Plague, as the bubonic plague was commonly known, is still present today, though at much lower transmission rates. The roof rat hosts fleas on its skin which bite the infected rat and then jump onto humans, biting them, and transmitting the disease. Bubonic plague can also be transmitted through the bite of an infected rat, but that is very rare.
Another disease that roof rats' carry is trichinosis. This can be contracted by humans through eating the meat of animals that have fed on rats. Food poisoning is also very prevalent in areas where rats have been able to get into food storage areas and contaminate them. Roof rats will contaminate much more food than they consume in areas where grain or seed is stored.
Rat bite fever is a flu-like illness that can be passed on through the saliva of an infected rat. If a roof rat bites you, clean the wound thoroughly with soap and water, use antibiotic ointment to dress it and watch for any signs of infection. Symptoms include headache, fever and nausea and can lead to swelling in the brain and organs.
The Hantavirus is another rat born disease. This is transmitted through droppings and urine of rats and mice. Roof rats have not been specifically linked to Hantavirus, but removal of any rat droppings should be done with utmost care.