Leprosy is an ancient disease, the oldest disease of which is associated with humans, with evidence of characteristic bone pits and deformities found as early as 2000 BC on cemeteries in India.
So it is only natural that many people think that the disease is a relic of the past. My studies in 2018 in a Brazilian state where the disease is common show that leprosy is closer to us than we would think. The disease grows in armadillos. And while these animals are not exactly the cuddly type to which people are drawn, the arms-to-human contact spreads. And when the species interact, reptiles give back leprosy.
An unsightly animal, a worse disease
Leprosy, also called Hansen’s disease, is caused by infection by the bacterium Mycobacterium lepraecausing skin lesions, nerve damage, disfigurement and disability, leading to social stigma commonly found in people with this disease. It is mainly spread by aerosol infection, or coughing and sneezing, from person to person.
Infection usually requires you to live in close contact with an untreated infected person. Symptoms develop slowly, as long as three to seven years after infection. It is rare in the United States, with an average of less than 200 cases diagnosed over the past ten years, mostly in individuals who have immigrated from abroad where the disease is common. It is mostly found in tropical countries such as Brazil, India, Indonesia and other countries in Africa, Southeast Asia and the Pacific Islands. There were 214,783 new businesses worldwide in 2016.
Although drugs to treat and cure leprosy are inexpensive and available free of charge to anyone diagnosed with the disease, the number of cases in dozens of countries has dropped significantly in recent years. The causes of the persistently high incidence are still poverty, poor sanitation and nutrition, and the lack of availability of health care to treat those diagnosed before nerve damage and disability occur.
Enter the armadillos
Dasypus novemcinctus, commonly known as the nine-banded armadillo in the U.S. or chicken armadillo in Brazil, is the only species whose variety includes North, Central, and South America. These armadillos first expanded their range from Mexico to Texas in the 1850s and then north and east into the Gulf states of the southern United States in the late 1940s another group of armadillos escaped from captivity in central Florida and spread throughout Florida. , which eventually merged with the Texan armadillos in the early 1970s in the Florida Panhandle.
Around this time, Dr. Eleanor Storrs found that armadillos were infected with M. leprae experimentally eventually came across symptoms of leprosy, even with the same skin lesions and nerve damage that occur in human cases. Shortly thereafter, she and her team discovered that armadillos living in the wild in Texas and Louisiana are naturally infected. M. leprae. Analysis of archived serum samples for antibodies specific for the bacterium indicated that animals from this area have probably been infected since the 1960s. Exactly how the armadillos became infected by humans is not clear, but one theory is that they picked it up from contaminated soil by digging. Surveys of armadillos in the Gulf states found that up to 20 percent were infected M. leprae.
Initially, armadillos’ susceptibility to leprosy was a boost to science and medicine. Because they were the only animal other than humans in which the bacteria could be isolated, armadillos allowed scientists to study leprosy and possible treatments.
There are now millions of armadillos in the southern United States, and people interact with them in different ways. The animals’ leather-like hoods were formed into purses and boots; some were kept in the house as pets or brought to entertain people at zoos, kindergartens and armadillo races at digging shows. In certain areas, people hunted them to serve at the braai.
All this exposure eventually had consequences. In 2011, dr. Richard Truman of the National Hansen’s Disease Program in Baton Rouge, Louisiana, published a study showing that the strain that infects the majority of armadillos and indigenous leprosy patients in Texas and Louisiana is identical, suggesting that the disease is a zoonotic infection. wash. is transmitted to humans.
In 2015, another study by the same group found that a different species that exists only in central Florida causes a second group of cases in armadillos and humans. Both of these reports caused a great deal of media coverage, and people were somewhat surprised and worried that this ugly and not very cuddly animal was transmitting the oldest and one of the most dreaded diseases to humans. Once the excitement subsided, most people probably resumed their behavior with these animals, and the potential risks associated with it.
What’s going on, come around: Same goes for Brazil
Two things stand out about Brazil. Armadillos are native to South America; and leprosy, first brought to Brazil by European explorers more than 500 years ago and by the slave trade from West Africa, has been occurring 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 would lead to leprosy transmission from these animals, as shown in the southern United States.
Our study focused on people living in a rural area in the western state of Pará in the Brazilian Amazon in the city of Belterra. People who live there regularly eat armadillos as protein sources. And there was a lot of interaction between people of this city and armadillos: 19% hunted the animals in the forests, and 65% cleaned the meat to cook or ate armadillos at least once a year. The percentage of people with a positive antibody response to the bacterium (63% were positive, normal for this region) indicated that the majority of people were infected by M. leprae.
A surprising 62% of armadillos killed by hunters showed signs of infection M. leprae, a rate three times higher than in Texas and Louisiana. Most importantly, a group of 27 individuals who ate mostly shingles meat had 50% higher antibody levels than other groups, suggesting that increased consumption nearly doubled the risk of disease. The study concluded that, similar to the southern states in the US, leprosy from armadillos is transmitted to people in Brazil.
The broader message about this work is that wild animals contain all kinds of diseases that can be transmitted to humans, especially if there is contact with blood or if the meat is eaten. Although leprosy is a disease that few people in the US worry about, they need to take care of the way they deal with armadillos.
This article was published from The Conversation, a non-profit news site dedicated to sharing ideas from academic experts.
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John Stewart Spencer receives funding from the Elevator Program of the New York Community Trust for Research in Leprosy and a J. William Fulbright Scholar to Brazil Award 2015-2016.