A Coconino County resident died of a rare case of pneumonic plague earlier this month. Dave Wagner, director of Northern Arizona University’s Pathogen and Microbiome Institute, spoke about the life cycle of plague and his research team’s efforts to develop a vaccine.
Tell me a little bit about the types of plague we have here in Northern Arizona.
Plague is a disease of rodents and their fleas. It’s been that way for thousands of years. And so you have an infected rodent that’s infected with Yersinia pestis, and a flea comes to take a blood meal. That’s what fleas do, they feed on blood. When they do that, then if the animal’s infected with Yersinia pestis, sometimes they pick up Yersinia pestis. So then the flea has it, and when it goes to feed on another rodent then it can transmit Yersinia pestis to that other rodent. So think of it as continuously cycling between rodents and fleas. That’s it’s whole thing.
So how often does it affect humans?
It’s really rare in the U.S. Typically in a year we’ll have 5 to 10 cases, human cases in the U.S…. By far and away, the most common form of human plague is what we call bubonic plague. That’s when it transfers from the environment, from rodents and fleas, into a human, via, usually, a flea bite. Left untreated, it can get into your bloodstream, which would be septicemic plague. And it can spread to your lungs then, once it’s in the bloodstream, and then become secondary pneumonic plague…. It’s a global disease. It’s found in North and South America, Asia, and Africa. And the place that has the most human cases is the place we’ve been doing research for 25 years, and that’s Madagascar.
What are the goals with your Madagascar research?
We are interested in improved diagnostics. So detecting an infection with Yersina pestis, because that’s crucial to detect it very rapidly, because then it can be easily treated with antibiotics. Untreated, it can be quite deadly.
So what would you like people who live in this area to know about these different forms of plague and what they can do to take care of themselves?
Recognize that it’s very rare. There are many other things to be worried about before plague. I don’t mean to minimize this tragic human fatality, but it is exceedingly rare. Watch your animals. Fre-roaming cats and dogs could bring fleas back, so flea collars are always a good idea…. Unfortunately the symptoms of plague are not always diagnostic. It’s things like fever, chills, and being tired, so that can present like lots of different things. If you think you have those symptoms, of course you should reach out to a medical professional and get evaluated for that.
Is there anything else you want people to know about the direction your research is taking, and what you’re hoping to see happen—how you’re hoping science is going to address this problem in the coming years?
We would be thrilled to develop, or help develop, a vaccine against plague. Because it really does affect really poor people in many parts of the world. There isn’t a big effort to come up with a vaccine. But it’s such a deadly disease and it’s pretty indiscriminate when people get infected, that having a vaccine would be really fantastic. If we can advance a vaccine and get it out there in a way that it’s available to people in remote areas that really need it, that would be fantastic.
Dave Wagner, thank you so much for speaking with me today.
It was my pleasure.
