infections
Leprosy
Introduction
Leprosy is a chronic infection usually caused by the bacteriaMycobacterium lepraeorMycobacterium lepromatosis. It results in damage primarily to the peripheral nerves (the nerves outside the brain and spinal cord), skin, testes, eyes, and mucous membranes of the nose and throat. Leprosy ranges from mild (with one or a few skin areas affected) to severe (with many skin areas affected and damage to many organs). Rashes and bumps appear, the affected areas become numb, and muscles may become weak. The diagnosis is suggested by symptoms and confirmed by a biopsy of the affected tissue. Antibiotics can stop leprosy from progressing but cannot reverse any nerve damage or deformity. People with untreated leprosy become visibly disfigured and often have significant disability, thus they have long been feared and shunned by others. Although leprosy is not highly contagious, rarely causes death, and can be effectively treated with antibiotics, it still has considerable social stigma attached to it. As a result, people with leprosy and their family members often have psychologic and social problems. Worldwide, the number of leprosy cases is declining. In 2020, about 130,000 new cases were reported, and about 73% of them occurred in India, Brazil, and Indonesia. In 2020, 159 new cases were reported in the United States. In the United States, most leprosy cases occur in people who worked in or emigrated from countries where leprosy is common. Over 70% of cases occurred in six states: California, Florida, Hawaii, New York, Texas, and Louisiana. Many of these cases occurred in people in southern states who had direct contact with nine-banded armadillos, which carry leprosy bacteria. Leprosy can develop at any age. Older age is a risk factor for leprosy, but the infection appears to develop most often in people aged 5 to 15 years or over 30 years. It is estimated that most people who are infected withMycobacterium lepraedo not develop leprosy because their immune system fights off the infection. People who develop leprosy may have genes that make them susceptible to the infection once they are exposed. 