Leprosy is an ancient disease, the oldest disease known to be associated with humans, with evidence of characteristic bone pitting and deformities found in burial sites in India as far back as 2000 B.C.
It’s thus only natural that many might think the disease is a relic of the past. My recent studies in a Brazilian state where the disease is prevalent shows that leprosy is closer to us than we might think, however. The disease is growing in armadillos. And while these animals are not exactly the cuddly type to which humans are drawn, armadillo-to-human contact is spreading. And, when the species do interact, armadillos are giving leprosy back.
What Goes Around Comes Around: The Same Is True in Brazil
Two things stand out about Brazil. Armadillos are native to South America; and leprosy, first brought to Brazil over 500 years ago by the European explorers and through the slave trade from West Africa, has been widespread there for hundreds of years. Knowing this, our research team wanted to know how much human contact there was with armadillos in Brazil and whether this could lead to leprosy transmission from these animals as had been shown in the southern US.
Our study focused on people living in a rural area in western Pará state in the Brazilian Amazon in the city of Belterra. People living there frequently ate armadillos as a source of protein. And there was a lot of interaction of people from this town with armadillos: 19 percent hunted the animals in the forests, and 65 percent cleaned the meat for cooking or ate armadillos at least once per year. The percentage of people with a positive antibody response to the bacterium (63 percent were positive, normal for this region) indicated that the majority of people had been infected by *M. leprae.
A surprising 62 percent of armadillos killed by hunters showed signs of infection with M. leprae, a rate three times higher than in Texas and Louisiana. Most importantly, a group of 27 individuals who ate armadillo meat most frequently had antibody levels 50 percent higher than other groups, indicating that increased consumption almost doubled their risk for disease. The study concluded that similar to the southern states in the US, leprosy is being transmitted from armadillos to people in Brazil.
The broader message about this work is that wild animals harbor all kinds of diseases that can be transmitted to humans, particularly when there may be contact with blood or when eating the meat. Although leprosy remains a disease that few people in the US worry about, people should take care with how they interact with armadillos.