Tuesday, November 13, 2007

Whatever Happened to the Bubonic Plague?

Eric York on right. The Mountation Lion did not get him, but the Black Rat Flea did.

A wildlife biologist at Grand Canyon National Park has died after coming down with the Bubonic Plague. Eric York, age 37, seems to have contracted the disease while performing a necropsy on a Mountain Lion which tested positive for the disease.

The good news about the Bubonic Plague is that it is now a treatable disease, thanks to antibiotics.

The bad new is that it it still with us.

Whatever Happened to the Bubonic Plague?

In school, no one ever mentions what happened to the Black Death. Nor do they mention that we now have it in this country. Like so much that is fundamental to history (Whatever happened to the Dust Bowl? Why did the Japanese bomb Pearl Harbor?), the question is sidestepped by grade-school teachers.




The vector, or transmission agent, for this wave of Bubonic Plague was the Black Rat, Ratus ratus, which was host to the Oriental Rat Flea, Xenopsylla cheopis, which in turn was host to the bacterium Yersinia pestis that actually causes the Plague.

Large-scale incidents of Plague in Europe ended with the arrival of a very aggressive new immigrant to Europe -- Ratus norvegicus, aka the Brown or "Norwegian" Rat.

In fact this rat is in no way Norwegian. It probably originated in Asia, and got to Europe through the Middle East, having first arrived in England on a load of timber from Norway (hence the name given to it by the British).

The Brown Rat and the Black Rat look somewhat similar, but they have very different temperaments. A Brown Rat is not only larger that its Black Rat cousin, it is also far more aggressive.


A Flea With an Affinity


Many types of flea also gravitate towards, and specialize in, certain kinds of hosts. Though a species of flea may theoretically be able to draw a blood meal from a wide variety of mammalian hosts, most thrive on a specific list of hosts and generally fail to thrive if these particular hosts are not around.

So it is with Xenopsylla cheopis, the Oriental Rat Flea, which is the flea most likely to be implicated in transmission of the Bubonic Plague.

The Oriental Rat Flea thrives on a few species of rodents, including the Black Rat and the Tarvag, or Monglian Marmot , which is found in the dry steppe country of central Asia. It may have been on on Tarvag skins carried along the Silk Road that the Plague first reached the Middle East around 541 AD.

While the Mongolian Marmot was probably the first host of the flea that carries the Bubonic Plague, the Xenopsylla cheopis flea has managed to due well on the Black Rat as well.

With the rapid spread of the Brown Rat, however, the Black Rat was bullied and beaten into extirpation across most of the civilized world.


Bottom line: the Bubonic Plague was brought to Europe by fleas riding on Black Rats, while Brown Rats largely drove that species of rat out of Europe (and much of the rest of the world), thus eliminating the Oriental Rat Flea and the Yersinia pestis bacteria that brought with it the Bubonic Plague. In short, rats not only brought the plague, they also worked to get rid of it.

A young Mongolian sharpshooter with Tarvags bound for the pot.

The Plague Comes to the New World

Plague-carrying Black Rats arrived on the West Coast of the U.S. in 1900 in a load of Chinese illegal aliens smuggled into San Francisco.

The exact date and circumstances are known, because two dead Chinese immigrants tested positive for the disease, and a massive roundup of rats was immediately begun.

Plague cases continued to bubble up in San Francisco for the next few years, but a local war on rats continued unabated, and it is possible the plague might been locally extirpated had the San Francisco earthquake of 1906 not hit.

The earthquake, of course, created a nearly-perfect environment of chaos, spilled food, and social disorder. After the earthquak, the Black Rat population began to climb, and with it the incidence of Plague.

Where was the Brown Rat? Believe it or not, Brown Rats (aka Norwegian rats) did not arrive on the West Coast of the U.S. until around 1940.

Eventually, a combination of poisoning and trapping, along with a massive city-wide cleanup, managed to knock down the Black Rat population of San Francisco and rid the city of the Plague.

Unfortunately, somewhere along the line, a Black Rat caught a train west, and with it Xenopsylla flea rode into the deserts of the American Southwest where it found the smaller, American version of the Tarvag -- the Prairie Dog.

A Prairie Dog, of course, is not a dog, but a type of small, communal-living, marmot.

Communal-living marmots and a dry climate presented the Xenopsylla cheopis flea with ideal living conditions, and it quickly multiplied. As a consequence, and to this day, Bubonic Plague can be found as a permanent feature of Prairie Dog towns (and, to a lesser extent, Richardson's Ground Squirrel colonies) in the American West.

It was, no doubt, from from a Prairie Dog that the Mounain Lion got the Bubonic Plague that was eventually passed on to National Park Sevice biologist Eric York.

Could the Plague Come East?

Could the Plague come East to take up residence in the common Groundhogs? For some reason this has not yet happened. It's hard to know what the barrier is, but the Xenopsylla flea may not find the Groundhog a suitable host -- perhaps they have a bad taste to the flea. As noted earlier, most flea species are very host-specific.

Another problem may be that it is simply too wet for the Xenopsylla flea to thrive in the kind of hedgerows we have here in the Eastern U.S. The Plague bacillus and its host flea generally thrive in desert or near-desert conditions. Though Europe is as cold and wet as the Eastern U.S, the Black Rats of the European Middle Ages tended to live under warm and dry roofs. The Xenopsylla flea apparently found this habitat quite suitable, while the wet and frozen hedgerows of the Eastern United States are the exact opposite of what the Oriental Rat Flea might consider home.



Anonymous said...

I love the way this it written!

LabRat said...

Plague is why I always spend some time fretting when, like yesterday, I find evidence the dogs have caught and killed some small animal.

Between it, hantavirus, and the tularemia that killed Kodos's dam, small fuzzy things always have a bit of an air of vermin to me even when they're minding their own business.

Paul said...

Welcome to Sedillo Hill, NM an exit on I-40 in the town of Tijeras, NM. Last year my neighbor died of plague, not bubonic, but the nastier septicemic variety. She was 54 and in good health, she felt sick for a couple of days and when her fever spiked up to 103 or 104 her husband brought her to the emergency room, she died hours later. Hers was the first death from plague in NM in 12 years, since then there was another death just a few miles away.

The carrier of the fleas in our area are rock squirrels, about the same size as an eastern grey squirrel but with a rattier tail. They dig warrens and live in the ground and are very elusive and tough to kill.

Plague is endemic in our neighborhood, the woman who we bought our house from in '93 had contracted it, caught it early and was cured. My son's best friends Mom caught it in '89 and wasn't diagnosed until it was well underway, she was cured but still feels crappy sometimes. All of the folks who've caught plague had cats - another reason not to.


Anonymous said...

Love your blog!! I found it a couple of weeks ago when looking for photos of a bear with mange (you probably heard about the camera station photos of "bigfoot" that were probably a bear with a severe case of mange). I keep coming back because your writing is excellent and the topics are fascinating. If you haven't already written a book on natural history, you should.

Lisa B.

Zara McDonald said...

It was not the Black Rat Flea as your article suggests that gave Eric the plague. It was his selfless devotion to wildlife conservation that put him in contact with this disease. He contracted the plague while performing a necropsy on of one the mountain lions in his study.

Eric was a unique individual who could work well with different personalities and in different cultures. His connection to wildlife and his unassuming manner were rare gifts and pleasures to witness. His endless knowledge caught anyone off guard because of his quiet nature. He showed a caring and thoughtfulness toward others that his rugged nature sometimes disguised from those who did not know him well. His work ethic was unmatched and his field capabilities were extremely special.

Eric was one of the most extraordinary individuals I have ever had the pleasure of knowing, and his contributions to conservation were not broadcast widely enough. He was preparing to join Felidae in Patagonia on December 15th to lead a capture team in the launching of a long-term ecological study where pumas will be a central focus.

Eric was often referred to as analogous to the animals he studied, in that he moved within their world so naturally. He pushed all of his limits to navigate impossible, and at times, risky terrain that required long field hours, with a firm dedication to answering some difficult conservation questions.

Learn more about Eric’s work at www.felidaefund.org

PBurns said...

I'm sorry for you loss. Eric sounds like a hell of a guy. That said, I did say he got the Plague while doing a necropsy on the lion. The lion, of course, got the Plague from the Black Rat Flea found on a Praire Dog. The Rat Flea and the Plague exist in this hemisphere because of the story told.

Perhaps some good can come out of this, if only to remind people about zoonotic diseases. The Bubonic Plague is a VERY treatable disease, and about $20 worth of antibiotics (or rubber gloves and a face mask) might have saved Eric's life.

For a listing of other zoonotic diseases (some of them devastating the planet) see >> http://terriermandotcom.blogspot.com/2005/07/sharing-death-and-disease-across.html


Steve Bodio said...

Paul--Hi Paul!-- is right about plague in NM, though oddly it might be a "good" place to catch it because local docs are very aware that iot exists. A few years back a tourist from Boston contracted it, broke out with it there, and died before being diagnosed.

There have been cases a few miles from me too but no deaths, though a cat died a couple of years ago near the ranch where I run my dogs. Most mammals can get it though some (canids?) seem to die of it less. But as Paul says rock squirrels are the big reservoir. (We call them "plague squirrels"-- Libby thought it was the actual name and I recall her telling a visitor at Bosque del Apache wildlife refuge that that is what they were!)

Country Mongolians are mad about marmots and hunt them obsessively. Son Jackson (Peculiar of Odious and Peculiar blog) has eaten them stuffed with hot rocks and thrown into a fire to burn the hair off. He said that after a month of boiled mutton it was delicious. I have never been so lucky-- the Kazakhs with whom I travel think it is nuts to eat marmot because of plague and because "they stand up like little people". Ulan Bataar has a ban on what Jack calls "marmot paraphernalia" but it is routinely violated.

There used to be a New Mexico T- shirt that Read "Land of the flea, home of the plague".

Personally I'd rather get plague than hantavirus- at least my doc claimed she could cure me faster and with fewer side effects. I do NOT give deer mice any space!

Anonymous said...

I'm so sorry for your loss. My love of the outdoors has been tempered by the crossover of disease from animal to human and tick to dog and I regret so much that I now have a fear of the forest. Surely, education and enlightened awareness of the dangers of the actually unknown(to most)risks of animal illness is key. I hope we will continue to learn and teach the reality of the natural hazards of life.