The Bubonic Plague Strikes Again on American Soil

By Jessica Vogelsang, DVM on Aug. 13, 2015

Yosemite is one of the nation’s most beautiful national parks. It’s also got a reputation for being a bit wild, with an average of 12-15 deaths a year. While most of those unfortunate souls perish by falling off Half Dome or getting swept over a waterfall, we now have the plague to add to our list of Yosemite dangers.

Surely not that plague, you ask? Black Death? The one that wiped out a good quarter of Europe in the 1300s? Yes, that very one. Carried by rodents and the fleas that live on them, this case was California’s first since 2006; earlier in the year, two people in Colorado died from the same disease. Plague joins hantavirus, another rodent-transmitted disease, as two of the microscopic dangers of camping in the valley.

Medicine and sanitation have improved since 1350, and the plague bacterium is treatable. On the other hand, improved medicine also has the tendency to make us complacent about the fact that nasty diseases are still out there.

Fortunately, the young victim in California is expected to recover. Local public health officials were savvy enough to ask the right questions and get to the correct diagnosis in time to help this child, but experts find themselves increasingly concerned about the possibilities of zoonotic disease in a highly mobile culture.

Veterinarians often find themselves unwittingly at the forefront of this public health battle when they see pets with vague signs of illness that could be caused by any number of things, only a handful of which are dangerous to humans. The mind tends to go to the obvious answers and skip the far-out-there ones; remember the man with Ebola in Dallas? Who would have expected that? Unfortunately, it’s small errors in oversight that can have tragic consequences.

Increased global mobility is also putting more pets and people at risk. As someone who lives in a border town, our veterinarians are more accustomed than some to asking the right questions from owners about travel history. However, with rescues flying pets into the U.S. from all over the world, veterinarians cannot afford to assume that any pet in front of them has lived a sheltered life with no exposure to really exotic diseases, so we need to ask about travel history—every time.

I recently spoke with a colleague who works in public health and she told me about a case she recently worked with: A dog visited its local vet with non-specific signs like fever and fatigue, which didn’t respond to any of their usual treatments. After multiple attempts to figure out the cause, Brucellosis was finally diagnosed. Because it is a reportable disease, the public health office was also notified.

Brucellosis is not common here in California, but the dog was adopted from Mexico. While Brucella is rarely fatal, it can cause significant illness and abortion in people. The owner was pregnant. Fortunately, she and the baby were all right, but she was terrified. She had no idea such a thing was even possible. As of last week. the rescue from which she adopted the dog still does not test dogs for Brucella before bringing them into the States.

I tell you all of this not to disparage anyone in the story but just as a reminder that animals can and do serve as a source of disease for people, and while most transmissible diseases are not life-threatening, the potential is there.

Just be careful, and don’t wait too long to call your vet if something seems off with your pet. And for goodness' sake, if you’re going to Yosemite, don’t feed the squirrels.