Transmission

How do people get Hansen’s disease?

It is not known exactly how Hansen’s disease spreads between people. Scientists currently think it may happen when a person with Hansen’s disease coughs or sneezes, and a healthy person breathes in the droplets containing the bacteria. Prolonged, close contact with someone with untreated leprosy over many months is needed to catch the disease.

You cannot get leprosy from a casual contact with a person who has Hansen’s disease like:

  • Shaking hands or hugging
  • Sitting next to each other on the bus
  • Sitting together at a meal

Hansen’s disease is also not passed on from a mother to her unborn baby during pregnancy and it is also not spread through sexual contact.

Due to the slow-growing nature of the bacteria and the long time it takes to develop signs of the disease, it is often very difficult to find the source of infection.

In the southern United States, some armadillos are naturally infected with the bacteria that cause Hansen’s disease in people and it may be possible that they can spread it to people. However, the risk is very low and most people who come into contact with armadillos are unlikely to get Hansen’s disease.

For general health reasons, avoid contact with armadillos whenever possible. If you had a contact with an armadillo and are worried about getting Hansen’s disease, talk to your healthcare provider. Your doctor will follow up with you over time and perform periodic skin examinations to see if you develop the disease. In the unlikely event that you have Hansen’s disease, your doctor can help you get treatment.

Who Is at Risk?

In the U.S., Hansen’s disease is rare. Around the world, as many as 2 million people are permanently disabled as a result of Hansen’s disease.

Overall, the risk of getting Hansen’s disease for any adult around the world is very low. That’s because more than 95% of all people have natural immunity to the disease.

armadillo

In the southern United States, some armadillos are naturally infected with the bacteria that cause Hansen's disease.

You may be at risk for the disease if you live in a country where the disease is widespread. Countries that reported more than 1,000 new cases of Hansen’s disease to WHO between 2011 and 2015 are:

  • Africa: Democratic Republic of Congo, Ethiopia, Madagascar, Mozambique, Nigeria, United Republic of Tanzania
  • Asia: Bangladesh, India, Indonesia, Myanmar, Nepal, , Philippines, Sri Lanka
  • Americas: Brazil

You may also be at risk if you are in prolonged close contact with people who have untreated Hansen’s disease. If they have not been treated, you could get the bacteria that cause Hansen’s disease. However, as soon as patients start treatment, they are no longer able to spread the disease.

Geographical Distribution of New Cases of Hansen’s Disease Reported to WHO in 2015
Map of Geographical Distribution of New Cases of Hansen’s Disease Reported to WHO in 2015

The distribution of new leprosy cases by country among 136 countries that reported to WHO in 2015. India reported 127 326 new cases, accounting for 60% of the global new leprosy cases; Brazil, reported 26 395 new cases, representing 13% of the global new cases; and Indonesia reported 17 202 new cases, 8% of the global case load. No other countries reported >10 000 new cases. Eleven countries reported between 1000 and 10 000 cases: from Africa, the Democratic Republic of Congo, Ethiopia, Madagascar, Mozambique, Nigeria and United Republic of Tanzania; from Southeast Asia, Bangladesh, Myanmar, Nepal and Sri Lanka; and from Western Pacific, the Philippines. Collectively, these countries reported 19 069 new cases, 14% of all new cases globally. The remaining 10 286 new cases (5%) were reported by 92 countries. Thirty countries reported zero new cases. Ninety-two countries did not report, several of which are known to have cases of leprosy. Source: Courtesy of WHOExternal