Synonyms Hansen's disease, hanseniasis, elephantiasis grecorum and names in local languages in endemic areas.
Definition A chronic infectious disease of man, caused by Mycobacterium leprae, affecting peripheral nerves, skin and sometimes other tissues.
Etiology Mycobacterium leprae, has been classified separately from the other mycobacteria because of the failure to grow it on artificial culture media. Mycobacterium leprae grows at 30-33oC, and divides every 12-13 days. It contains few antigens as compared with BCG but the phenolic glycolipid found in the foamy capsule is biologically unique and antigenically specific to M.Leprae.
Incidence In 1999, the world incidence of Hansenís disease was estimated to be 640,000; and in 2000, 738,284 cases were identified. In 1999, 108 cases occurred in the United States. In 2000, WHO listed 91 countries as endemic, with India, Myanmar, and Nepal having 70% of cases.
Epidemiology Although the mode of transmission of Hansen's disease remains uncertain, most investigators think that M. leprae is usually spread from person to person in respiratory droplets. The clinical incubation period is usually 3-5 years and the disease tends to have a bimodal age distribution, with peaks at 10-14 and 35-44 years.
Risk Groups Close contacts with patients with untreated, active, predominantly multibacillary disease, and persons living in countries with highly endemic disease.
Clinical Features This chronic infectious disease usually affects the skin and peripheral nerves but has a wide range of possible clinical manifestations. Patients are classified as having paucibacillary or multibacillary Hansen's disease. Paucibacillary Hansen's disease is milder and characterized by one or more hypopigmented skin macules. Multibacillary Hansen's disease is associated with symmetric skin lesions, nodules, plaques, thickened dermis, and frequent involvement of the nasal mucosa resulting in nasal congestion and epistaxis.


Worldwide, 1-2 million persons are permanently disabled as a result of Hansen's disease. However, persons receiving antibiotic treatment or having completed treatment are considered free of active infection.
Challenges The main challenges for Hansen's disease elimination efforts are to reach populations that have not yet received multidrug therapy services, improve detection of disease, and provide patients with good quality services and free drugs.
Treatment The principles of treatment are: chemotherapy, prevention and treating reactions, educating the patients to cope with existing nerve damage and rehabilitating them socially and psychologically.