It appears that the plague is making a comeback. You read that correctly. The same illness that ravaged much of the world in the Middle Ages and that became known as the Black Death has recently shown up in the American West.
Since the beginning of this year, three people in New Mexico have caught the plague, though none have died. Two had the bubonic form of the disease, which causes painful lumps (called “buboes”) to develop in the lymph nodes. One of the patients caught the more virulent pneumonic form of the plague, which hits the lungs and is highly deadly. All three of the patients have been treated and released, though the pneumonic plague victim suffered some lasting organ damage. Although this is a far cry from the millions of people affected by historic outbreaks of the disease, it is still unsettling.
The bacteria that causes the disease, Yersinia pestis, has not changed much since it first struck human populations hundreds of years ago. Traces of the bacteria extracted from the teeth of human remains have even helped researchers identify past plague victims buried in large burial pits. New Mexico typically experiences a few cases a year, though the number of cases will likely be higher this year. But there are many more cases in Africa.
Fortunately for the American victims, good hygiene and the availability of antibiotics means that very few of them will die. In less developed areas, over half of those who catch the plague will die if they don’t receive treatment quickly.
Though the plague is carried by rodents, it is actually the types of trees found in New Mexico that make it the perfect environment for the disease. The state is home to many juniper and pinyon trees, which rodents love to live in. These rodents are almost always infested with fleas that carry Yersenia pestis.
Squirrels, particularly rock squirrels, and prairie dogs are a major source of these fleas. They enter people’s yards, leaving fleas as they go. These fleas then hitch a ride on family pets and end up biting humans, thus spreading the illness. The fleas have also been known to bite humans who are out hiking in the areas where their rodent hosts live.
Though the plague is scary, there’s no need to pack your bags and leave New Mexico. Just make sure that you keep the areas near your home free of woodpiles and junk, since rodents like to live in these places. Also, you should use flea control products on all pets and keep their food and water bowls inside, so that rodents aren’t attracted to them. If you like to hike, wear insect repellent and protective clothing. Finally, if you live in a plague-affected area, and you develop a sudden illness, see a doctor as quickly as you can.