Rats carry over 70 diseases and a large number of them can be fatal to humans. Some of the most dangerous diseases that rats carry include bubonic plague and leptospirosis.
Bubonic plague is just one type of plague that rats spread. The actual cause of the plague is the bite of the rat fleas that inhabit the rats. The rats act as hosts to these fleas, which can spread other diseases, such as typhus and trichinosis. Rats who have the plague-infested fleas on them can also spread bubonic plague through their bites.
Leptospirosis is a renal disease that can cause kidney failure and liver failure. The disease is spread through the infected rats urine. Dried particles of urine or fecal matter can be inhaled, which transfers the disease to humans. Hantavirus is also spread through rat waste as well. Victims will breath is the particles from the dried waste to contract the virus.
Rat bite fever, although rare, is transmitted through the bite of a rat. This disease manifests itself with flu-like symptoms, which get worse and can result in swelling of the brain and other organs. In rare cases, rat bite fever will not present any major symptoms.
The danger of handling rats and their waste can be mitigated by proper protection. Wear gloves and a mask when touching or cleaning up any rat droppings or urine, and certainly the dead rats themselves. The rat fleas that carry the plagues and other diseases usually evacuate the dead animal and will search for a new host. Extreme caution must be taken when discarding a dead rat, as the fleas can travel to humans. Wear long sleeved clothing and long pants. Discard the clothing after you remove the rat.