Question

I read something recently about a guy getting plague! I thought that plague and the days of the Black Death were long gone. Can you still get plague from rats?

Answer

You will more likely get the Plague from prairie dogs and rock squirrels rather than brown rats.

Surprisingly, plague is still around and you could still get it, but not from our usual brown or black rats. Every year in the U.S., there are an average of 10-15 cases of plague reported, mostly in the western U.S., and mostly from contact with rock squirrels or prairie dogs (both are rodents). Worldwide, there are between 1,000 to 3,000 cases annually.

Plague is caused by bacteria and is spread by the bite of an infected rat flea or by handling an infected animal. While plague was once an urban disease attributed to city rats, most cases today occur in rural areas of Arizona, California, Colorado, and New Mexico. These cases are traced to prairie dogs, ground squirrels, gophers, other wild burrowing rodents, rabbits, or animals that have come in contact with them.

The version of plague carried by rat fleas that caused the Black Death in 14th century Europe killed between one-third and two-thirds of the population! Recently, researchers studied the remains of more than 100 plague victims buried between 1348 and 1350 and found that the Black Death was caused by a strain of the plague bacteria that no longer exists. Other versions of the same bacteria are still with us, but today they’re associated with fleas on wild rodents, not urban rats. Another reason plague no longer causes widespread deaths is that it is fairly easy to suppress with sanitation and rodent control, the use of modern antibiotics, by isolation, and by the use of pesticides to kill fleas.

So the bottom line is you really don’t need to be concerned about plague unless you have contact with burrowing rodents, or with pets who have had contact with burrowing rodents, in certain plague areas of the southwestern U.S. Those most at risk of getting plague are wildlife biologists, trappers, hunters, campers, hikers, veterinarians, or pet owners in these areas. Residents need to keep pets flea-free since pets bringing in rat fleas from outdoors have been implicated in some human cases of plague. In plague outbreak areas, the Centers for Disease Control advise that residents avoid sick or dead animals, and that those individuals working with wild animals use repellents, wear protective clothing and gloves when handling trapped animals, and stay away from rodent nests where fleas may be waiting.

There is a concern today that plague could be used as a bioweapon by terrorists or others. The plague bacteria occur in nature and are easily grown in a laboratory. If they were released in an aerosol attack, one to six days later people would develop pneumonic plague. This form of plague can be spread to others through close contact. Federal and state officials assure us that they have large supplies of the antibiotics needed to treat a plague outbreak. Antibiotics must be given within the first 24 hours after symptoms appear, or death can result. There is no plague vaccine currently available.