Scientific advances in leprosy research: tracking down the origins of leprosy
In many parts of the world, especially in India, Africa and Brazil, millions of people still suffer from leprosy. Scientists have now come closer to the origins of the infectious disease by analyzing the genetic makeup of medieval leprosy bacteria.
Common ancestor 4,000 years ago Although leprosy is considered curable, up to four million people worldwide live with mutilations caused by leprosy. The symptoms of chronic infectious disease vary greatly from patient to patient. In the early stages, there are typical blurred spots on the skin. The disease used to be called leprosy because the victims were “abandoned” and had to live outside human settlements. Geneticists now rely on the DNA decoding of the pathogen and were able to determine from medieval leprosy bacteria that the genetic makeup has hardly changed over the centuries. In addition, it was analyzed that many of the bacteria can be traced back to a common ancestor who lived 4,000 years ago, according to the team led by the Tübingen evolutionary geneticist Johannes Krause in the journal "Sciencexpress" Current samples of living leprosy patients fall back on, and the researchers were able for the first time to reconstruct entire genomes of the pathogen Mycobacterium leprae from different epochs.
Hardly any changes in the past millennia There have hardly been any mutations in the genetic material of the pathogen over millennia and, according to Krause, this allows conclusions to be drawn about the disease. For example, the realization that leprosy was relatively evenly distributed for millennia and did not occur in several pandemics like the plague, for example. The widespread spread of leprosy in the Middle Ages is not due to the pathogen, but to the changing living conditions of people. The spread increased when people lived together in ever larger settlements in the 10th century. And in the 14th century, it was contained by improved hygiene standards, said Krause. Research on the leprosy genome also made it clear that the DNA of bacteria is preserved much longer than that of mammals, even under unfavorable environmental conditions. "This should make it possible to trace the disease back to its prehistoric origins," said Krause.
Many people without access to effective medication Findings about the origins and changes in the disease can be relevant to medicine. If, for example, it is known how quickly bacteria mutate, it is easier to estimate how quickly they will become resistant to new antibiotics. The professor said it was not yet clear whether there would be research projects that attempted to make the DNA decryption of the leprosy pathogen usable for medicine. However, it is conceivable that a suitable antibiotic could be determined for each patient with the help of simple DNA analyzes. Every year, more than 200,000 people worldwide still develop leprosy. According to the German Leprosy and Tuberculosis Aid (DAHW), up to four million people have mutilation caused by leprosy. The disease is most common in India, but is also common in Africa and South America, for example in Brazil. Leprosy cases also occur in the United States, where armadillos are responsible for causing illnesses. In Europe there is still the Sanatorio San Francisco de Borja in the Spanish village of Fontilles in the hinterland of the Costa Blanca, which has been specially set up for the treatment of leprosy sufferers. Basically, leprosy is curable, but especially in the poor regions of the world, many people have no access to the medicines that help. With the help of the drugs, the leprosy pathogens could be completely killed in 6 to 18 months. (sb)
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