Hansen’s disease, also known as Leprosy, is a chronic disease resulting from infection with a bacterium known as Mycobacterium leprae. The bacterium multiplies very slowly and mainly affects the skin, nerves, and mucous membranes. There are two common forms of the disease, tuberculoid and lepromatous, and both forms produce sores on the skin.

New cases of Hansen’s disease in the U. S. are few, diagnosed mainly in California, Florida, Hawaii, Louisiana, Texas, New York City, and Puerto Rico.

Hansen’s disease is reportable to the Iowa Department of Public Health by Iowa Administrative Code 641 IAC 1.


Symptoms of Hansen’s disease can appear anywhere from nine months to 20 years after exposure. Symptoms include:

  • Skin lesions (located identically on both sides of your body) that are numb and do not heal after several weeks or months
  • Numbness or absent sensation in the hands, feet, or legs
  • Muscle weakness and paralysis

The lepromatous form can also result in a chronically stuffy nose.


Although how Hansen's disease is spread remains uncertain, most investigators think that M. leprae is usually spread person-to-person in respiratory droplets after prolonged close contact. Most people probably are not susceptible.

Risk Factors

Children are more susceptible to Hansen’s disease than adults. Also, people in close contact with infected individuals for long periods of time are at an increased risk of becoming infected.


Prevention consists of avoiding close physical contact with infected individuals who are not being treated. Patients who have been treated with effective antibiotics for three days are no longer considered contagious. People with Hansen’s disease, including health care providers, can return to their regular activities (including work and school) after receiving effective treatment for three days.


There are effective antibiotics available to treat Hansen’s disease. These drugs must be given long-term (at least two years) in order to be successful. Anyone who suspects they may be suffering from this disease should consult their health care provider.


There was one case of Hansen's disease reported in 2020, and no cases reported in 2021.

For more detailed information and statistics on all notifiable diseases, please see our current annual report located in the reports section of the CADE homepage.

Additional Resources