Hansen’s disease: A research like no other

Published 4:57 pm Tuesday, May 12, 2020

Writer’s Note: If any word has made a resurgence lately, it’s “quarantine.” But the truth is, whether used as a noun or as a verb, it’s really no stranger to the American vocabulary. This column is the fourth in a series related to a quarantine in our sister state that lasted nearly half a century. Please note that leprosy is now called Hansen’s disease.     

On Jan. 13, the Louisiana State University football team won the national championship. While it’s not unusual for the Tigers to get attention on the field, it’s the school’s nine-banded armadillos that post victories of scientific consequence.

That’s right. Just a few “Joe Burrow” passes away from Tiger Stadium, researchers care for more than a hundred of the scaly critters. They make up the only armadillo colony in the world, one that’s maintained by The National Hansen’s Disease Programs (NHDP) laboratory located at LSU. In the past, research was conducted at a lab an hour south at Carville. During the 20th century, Carville was home to the only leprosarium in the continental United States, a place where hundreds of patients were quarantined because of leprosy. 

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These days, the NHDP lab chief is Linda Adams, a petite, carefully spoken woman with long hair and blue eyes. She says Hansen’s disease has never been easy to study. “The thing about the leprosy bacterium is you cannot grow it in the lab. It will not grow in a Petri dish, and it doesn’t have the genes necessary to grow independently. It must be grown in an animal model. We have no choice.”

So finding an animal that could be infected and used for research was a top goal for decades. In this case, temperature was key. According to Adams, armadillos have a core body temperature of about 33 degrees Celsius. “Leprosy bacterium likes the cool areas,” she explains. “That’s why it affects the skin and the mucous membranes. These are cooler areas of the body. So, the armadillo is a very good host. We can grow tremendous numbers of bacteria in the armadillo.” 

Three scientists and nine technicians make up the program’s staff. They include biologists and immunologists, and new citizens from Argentina and India. On the morning I visited, I watched a woman in a white lab coat prepare tissue samples for special staining that will allow visualization of the leprosy bacteria. In another room, two technicians wearing disposable garb had their hands beneath the hood of a biological safety cabinet. They were performing tests to see if a new drug had killed the bacteria. 

For Adams, the space — with its climate controls, whirring machines, and camera/microscope combos  — is a draw. “I knew I wanted to work in the lab since I was a child,” she says. “I loved science, but I never thought I would be doing leprosy research.”

She acknowledges their program isn’t a fit for all scientists: “It takes a special personality to do this sort of work, because our experiments can sometimes take a one or two years to run. It takes a special kind of person to have that sort of patience. You’re not going to get a publication every month if you come and do this type of work.”

In 2011, the Hansen’s Disease Center research team verified a theory long suspected by locals. They determined Hansen’s disease occurs naturally among some free-ranging armadillos, the kind you find in wooded areas of southern coastal states. Establishing a possible human-to-armadillo contact link was significant.

The laboratory maintains a ready supply of M. leprae bacilli for researchers worldwide, but they’re also doing other studies with their colony. Armadillos can live up to 15 years. That’s long enough for the slow-manifesting effects of Hansen’s disease to emerge.

“They actually develop the disease and get the nerve infection, and that’s what causes the damage in most patients. Bacteria infects the nerve and damages the nerves, and that’s what causes the disabilities,” Adams explains.

The scientists at LSU are constantly testing new drug therapies on the armadillos. According to Adams, those include antibiotics being tested for tuberculosis, because TB bacterium and the leprosy bacterium are closely related. The bulk of the research at LSU, however, is focused on figuring out how Hansen’s disease is transmitted. Staff also published results last year from important trials for a vaccine. But how a vaccine would be administered is still a question.

“Leprosy is a rare disease, so who would you vaccinate? Everyone? Contacts? Patients who already have leprosy?” asks Adams. “But if we could treat someone who already has the disease and actually improve and shorten treatment, that would be beneficial.”

Leprosy is rare in the United States, but globally there were more than 200,000 new cases of leprosy reported in 2018. That means developing a vaccine would be a real breakthrough.

Kim Henderson is a freelance writer. Contact her at kimhenderson319@gmail.com. Follow her on twitter at @kimhenderson319.