The Actual Plague is Appearing in New Mexico -- and Scientists Think They Know Why

Plague is usually connected to bad hygiene and poor living conditions. Plague comes from fleas that live on rodents. We don't normally live with rodents who have fleas in this country anymore.

So what is happening with plague cases showing up across the West and in New Mexico specifically?

Three people in New Mexico have been reported to have the plague this year. All three were treated at Santa Fe area hospitals and released. Every few years a handful of people come down with the plague in New Mexico. Only one person has died. Not exactly the Black Death that it once was, but still a serious disease. 

The Yersinia pestis bacteria is the bacteria that causes the plague today. It is very similar to the bacteria that caused the Black Death. The difference is that we live in the age of antibiotics and the disease is not the threat that is once was. Also, we have a much higher level of hygiene and water treatment than was the case in the Middle Ages when the Black Death killed millions across Europe. 

The plague has three strains that show up in humans according to the CDC. bubonic plague, pneumonic plague and septicemic plague. Many people thought that the disease had died out, but it is still a very serious disease that infects thousands. From 2000 through 2009, there were 21,725 reported cases of plague worldwide, according to the American Society for Tropical Medicine and Hygiene.  Only 1,612 of those cases were fatal.

Bubonic plague is quite deadly with 50 to 60 percent of cases causing death if not quickly treated, according to the World Health Organization. It is the most common form of the plague and is marked by swollen lymph nodes in the groin or armpits. 

Septicemic plague causes extremities to go black and sometimes die off. It caused by handling an infected animal or by getting bitten by a flea coming from an infected animal. 

Pneumonic plague causes a rapid and severe type of pneumonia. it is the only version that can be spread person to person through the air or by inhaling infected droplets of water. 

Most plague cases have been found in Africa since the 1990's specifically The Congo and Madagascar. However there have been cases in Asia and North and South America. 

The reason that so many cases are showing up in New Mexico is because of the vegetation found there. Particularly the large population of pinyon and juniper trees. these types of trees support a large variety of rodents. Rodents are the most common carriers of plague because of their propensity for carrying fleas according to Paul Ettestad, the public health veterinarian for New Mexico.

"A lot of people have rock squirrels in their yard, and when they die, their fleas are very good at biting people," Mr. Ettestad said. "We have had a number of people who got plague after they were bitten by a flea that their dog or cat brought in the house."  

Most people allow their dogs to come into the house with them. That is where the fleas strike humans and the plague is contracted. 

"What we see in the West here is the fleas will crawl up to the entrance of the burrow and wait for a host to come by," according to Ken Gage at  The Centers for Disease Control and Prevention.  "If they get on another rodent that they can live on, then they've been successful. But they can also jump on humans, or on dogs or coyotes or cats, which aren't the right hosts, but unfortunately those animals can be bitten by the fleas and get plague." 

Is it possible that by snuggling up close to your dog, we are going back in time to being as dirty as people were in the Middle Ages? Next time you kiss your dog -- I kiss mine all the time -- think about what he just had his nose in.