EYDER PERALTA, HOST:
A recent research letter to the Centers for Disease Control and Prevention is raising eyebrows amongst medical professionals and the general public. While the U.S. still has very few cases of leprosy, a team of doctors have identified an uptick in cases across the country, and 80% of them are coming from the state of Florida alone. Stranger still, 20% of all cases were identified in one single region of the Sunshine State, Central Florida. We have the authors of that letter, both dermatologists on the line now, Dr. Rajiv Nathoo and Charles Dunn. Thank you for joining us.
RAJIV NATHOO: Thank you for having us.
CHARLES DUNN: It's a pleasure.
PERALTA: So before we get into the specifics of your research, Dr. Nathoo, could you remind us about what leprosy is exactly?
NATHOO: Absolutely. So leprosy is a bacterial condition caused by a bacteria called Mycobacterium leprae - very slow-growing, and it has a tendency to involve the skin and the peripheral nerves.
PERALTA: So if you have leprosy, how do you know? What are the symptoms?
NATHOO: So either as mild as a few patches on the skin that tend to be hypopigmented or as severe, on the other side of the spectrum when their immune system is not doing well with the bacteria, of multiple widespread papules and nodules or bumps, essentially, across the skin with other characteristic features like a thickening of the forehead skin or an enlargement of the ears.
PERALTA: Dr. Dunn, how do people in the U.S. usually contract leprosy?
DUNN: Typically through prolonged contact via respiratory droplet with someone who has untreated disease. And I think it's important to note that in this situation, we're talking about many months. We're not talking about hours or days. Now, in the United States, it's important to note that a good portion of these cases, we actually do not have reported close contact with someone who has untreated disease. It's just such an uncommon illness. And in these situations, it's a little bit of a conjecture. One of the main theories out there is that it's transmitted to people from animals. And the most common vector or animal that we know that carries this bacteria is the nine-banded armadillo.
PERALTA: Is it easy to treat?
NATHOO: Yes. Treatment consists of a multidrug regimen for several months depending on what clinical variation of leprosy they have. And important to note that within, you know, a few days of treatment, the effect of the contagious aspect of things tend to dissipate.
PERALTA: So, I mean, it sounds like what you guys are telling me is that it's difficult to contract. It's easy to treat. So why is this still around? Why is leprosy still around?
DUNN: That's a very educated question and one that I don't think that we have a perfect answer for. And part of the reason is because of the unique nature of this bacteria. So this is a very slow-growing bacteria that replicates over the course of years. So whenever you're contact tracing a bacteria like this, it's not like I can ask you, where were you 24 hours ago in that you contracted this illness? This is the equivalent of me asking you, what did you have for dinner seven years ago? Well, I can't tell you what I had for dinner yesterday. And so contact tracing can be very challenging. So I can tell you that the suspicion that we have is that the complexity of the zoonotic component of this is expanding for reasons that we don't fully understand yet.
PERALTA: So the U.S. averages 150 to 200 cases per year. That's a pretty small number. And both of you have been very clear that the letter that you've written should not be used to drum up any kind of panic, that people should view this all in its proper context. So what is it that you hope folks do with this information, Dr. Dunn?
DUNN: This is more of a observation that we were hoping to impress upon the clinical community to encourage us to not get our blinders on when we are seeing these patients, No. 1, and maybe to dig into the why, maybe to explore more of the environmental component to this disease process to see if we can drive those numbers even lower.
PERALTA: Dr. Nathoo, as far back as records go, leprosy has carried quite the stigma. My colleague Pam Fessler wrote a book about how biblical stories of punishment led to the mass confinement of people who contracted the disease just a century ago.
PAM FESSLER, BYLINE: It all worked together for the public to basically demand that public health officials do something about this. We need to confine these people and get them out of our streets and our communities.
PERALTA: Do you think that this kind of stigma still affects us today, still haunts this disease?
NATHOO: Absolutely. I think that's why it's garnered such media attention and the fear of high contagion. And that's quite the opposite. It's not highly infectious. Most folks are not susceptible to infection. Ninety-five percent of the human population is not susceptible to infection.
PERALTA: Most people, 95% of people, are not susceptible to this disease. Why?
DUNN: The reason that 95% of the human population is not susceptible to infection is because there's an innate immunity to this bacteria present in 95% of the population.
PERALTA: So what's next? What questions do you both have that you would want to answer? And what questions do you have about this disease in Florida?
NATHOO: Right. I think the biggest question that we have would be in regards to that environmental reservoir. We've noticed that there - the soil specimens have shown Mycobacterium leprae in the past. But what does that mean? Is that a mechanism of disease transmission, or is that just a simple finding that has no clinical relevance? So we need to hone in in the scientific community in terms of transmission.
PERALTA: Dr. Rajiv Nathoo and Dr. Charles Dunn. Thank you for speaking to us today.
NATHOO: Thank you.
DUNN: It's truly a pleasure.
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