May 4, 2023 Author : Saraiva da Cunha Leprosy, also known as Hansen disease or Lazarus disease, is a chronic infectious disease . It is caused by the bacteria Mycobacterium leprae and Mycobacterium lepromatosis , together called Mycobacterium leprae complex. Mycobacterium leprae mainly affects the peripheral nerves, skin, eyes, and nasal mucosa . The long history of this disease and the prejudice that was once associated with it, make fears still arise when talking about leprosy. However, it is known today that leprosy is not easily transmitted, and that it is a curable disease . Treatment prevents deformities and disability, often permanent, linked to the evolution of the disease, provided it is started timely and carried out to the end. How is leprosy transmitted? The way in which leprosy is transmitted is not completely understood , but it is known that: It is mainly respiratory, by inhaling the droplets expelled through the nose and mouth of infected people. More rarely, Mycobacterium leprae can penetrate through skin lesions. For transmission to occur, close and frequent contact, over time, with untreated infected people is required. The disease is not transmitted in sporadic contact with someone infected, it is not transmitted from mother to child, nor through sexual intercourse. In addition, most people do not develop the disease after being exposed to patients, which is now known to be related to the genetic and immune characteristics of each person and also to external factors: Only 5% of exposed people become infected; Of these, only about 20% develop the disease. Symptoms of leprosy Leprosy has a prolonged incubation period , on average 5 years. However, up to 20 years can pass between the infection and the first symptoms. The symptoms depend on the tissues affected and the stage of the disease and can lead to deformities and serious and permanent disability. As nerves are affected the is loss of sensation , with greater likelihood of injury, muscle weakness, swelling of nerves under the skin, paralysis and loss of extremities; Skin lesions can range from flat and limited discolored patches, dryness, thickening and flaking of the skin, to the formation of raised nodules; Corneal ulcers and blindness are possible ocular complications; When the nasal mucosa is affected, hemorrhages, loss of smell, even deformities of the nose and neighboring areas may occur . Diagnosis and treatment Early diagnosis and treatment are essential for the disease not to evolve , causing deformities and severe and permanent physical disability. The diagnosis is based on symptoms, mainly cutaneous and neurological, as well as results of skin biopsies. More often, at the time of diagnosis: The most resistant people have one to three lesions on the skin, well defined, flat, with a paler central zone and reddish periphery, and insensitive. At the other extreme, less resistant people have multiple skin lesions, poorly defined, raised or nodular, and spread over the body. Treatment is done with a combination of two or three antibiotics taken for 6 to 24 months, depending on the number of lesions at the time of diagnosis and other particularities of each case. When treatment is started, infected people stop transmitting the disease and can have a normal daily life . This treatment is curative in that it eliminates the bacteria that cause the disease and prevents the progression of the disease. However, it does not resolve deformities or disabilities that are already present when it is started. That is why it is so important that it is done as early as possible. Prevention It has not been possible to eliminate leprosy by treating only diagnosed cases. Thus, to prevent the spread of leprosy, WHO also recommends identifying close contacts of diagnosed cases and perform their preventive treatment with a specific antibiotic. From elimination to eradication Fighting leprosy has been part of WHO actions and the importance of the disease is gradually diminishing . In 1985, leprosy was still a public health problem in 122 countries. In 1991, WHO was tasked to develop an elimination strategy and increased geographic coverage of treatment and improved patient access. In 2000, the disease ceased to be a public health problem, that is, its prevalence dropped to less than 1 case per 10 000 people. WHO goals for 2021-2030 include the eradication of leprosy, with various measures to reach zero cases of infection, disease, disability and stigma and discrimination associated with this disease. For now, new cases continue to be diagnosed every year. In 2021, 140 546 were registered . Brazil, India and Indonesia were the countries with the highest number of new cases, more than 10 thousand; 10 countries reported between 1000 and 10 000 cases; 36 countries reported between 100 and 999 cases; 55 countries reported less than 100 cases; 31 countries reported no cases; 59 countries did not report data. In Portugal, between 2015 and 2021 (provisional data from the SINAVE multi-annual report) a total of 35 imported cases of leprosy were reported (27 confirmed and 8 probable); there were 6 new cases of leprosy in 2019, the maximum value in recent years. In 2010, 15 cases were reported and in 1975 the cases were 49. Between March and April 2023 , 2 imported cases of leprosy were reported in the Autonomous Region of Madeira and in the North Region of Portugal, both in persons from Brazil, a country where the disease is endemic. References Centers for Disease Control and Prevention. Hansen’s disease (leprosy) . Serviço Nacional de Saúde: Doenças de Declaração Obrigatória . World Health Organization. Leprosy . Meet the infectious diseases clinical team from Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
