Leprosy (Hansen's Disease)

Hansen’s disease, historically known as leprosy, is a disease caused by the bacterium Mycobacterium leprae. This bacterium, unlike that which causes cholera, cannot survive in the environment and thus must be transmitted from host to host without interruption. Though its mode of transmission has not been proven, it is suspected that it passes through the inhalation of droplets such as those one would cough or sneeze, not through skin-to-skin contact, as was long believed (NIH, 2019). Like its cousin tuberculosis (Mycobacterium tuberculosis), one must be in prolonged contact with an infected individual to contract Hansen’s disease. It is likely the oldest human-specific infection, having begun coevolution with early humans or even hominids millions of years ago (Han & Silva, 2014). It has historically been highly stigmatized due to its long-unknown transmission and its disfiguring symptoms.

The disease affects primarily the skin, nerves, and mucous membranes, like the eyes, nose and mouth. The skin may develop large, flat, often numb lesions, or growths (nodules) (CDC, 2017). The most disabling symptoms come from leprosy’s ability to affect the peripheral nervous system, i.e., those nerves that register pain, pressure, as well as those that control movement. A lack of sensation will often cause injuries to go unnoticed, causing extensive damage and possibly infection. In severe cases, the body will begin to reabsorb damaged digits, resulting in shortening or loss of fingers and toes. Nerve damage can also cause paralysis, usually of the hands and feet. Advanced disease can cause blindness. Left untreated, Hansen’s can be a highly disabling disease.

Hansen’s disease can be cured without permanent damage if found in a timely fashion. The medication dapsone was discovered in the 1940s, which was the first biomedical treatment. Dapsone was a long-term medication, often lasting a lifetime. Resistance to the drug was mounting when rifampicin and clofazimine were discovered in the 1960s, which were then recommended in conjunction with dapsone, leading to multi-drug therapy (MDT). MDT is the standard regimen to the present. Treatment typically lasts six to twelve months. Since 1995, the World Health Organization (WHO) has provided MDT for free (WHO, 2019).

One of the defining features in the history of leprosy has been the stigma associated with it. Those suffering from Hansen's disease, referred to as “lepers,” were often seen as suffering by the divine will of God, a view fortified by the wealth of references to leprosy in the Bible. In the late nineteenth and early twentieth century, Columbia approached infection as “a disease apart” from other infections, isolating those with leprosy in leprosaria or lazarettos, institutions much like the sanatoria used for isolating tuberculosis patients (Obregon, 2003). This kept them out of sight and out of general society. The disease, especially if left untreated, can be very disfiguring, clearly demarcating those with with it for the duration of their lifetime. As such, those who had Hansen’s disease often had difficulties finding a place to live or work. Thus, leprosy can contribute to a vicious cycle of poverty.

Leprosy has been officially “eliminated” worldwide as a public health problem (meaning a prevalence of less than 1 case per 10,000) since 2000. However, it is still unequivocally present, with 211,009 new cases reported worldwide in 2017 (WHO, 2019). It has found a reservoir in armadillos, which have a body temperature slightly cooler than humans’ (around 90 degrees Fahrenheit), which the bacterium thrives in . Contact with these creatures, through hunting or otherwise, has been found to transmit Hansen’s disease to humans in the Americas. However, armadillos are not a natural reservoir of the disease; humans were responsible for transmission to armadillos a few hundred years ago, with the invasion of European settlers, who were responsible for bringing the bacterium to the New World (Clark, 2015).

Brazil has the highest incidence and second highest prevalence of Hansen’s disease in the world, following India. The country has hotspots of leprosy, or highly endemic areas, which house 11.2% of the population (Penna et. al., 2009a). These areas are found mainly in the western, Amazonian region of Brazil, with the most tropical climate (Penna et. al., 2009b). Residents of these areas report consuming armadillo meat, which doubles the likelihood of contracting the disease (Deps, 2008). Currently, Brazil’s endemic regions remain so due to the country’s size and the challenges associated with a lack of continuous care. Leprosy requires long-term treatment, usually around 12 months, which can be complicated or extended by drug-resistant strains of bacteria or co-infection with HIV (Martins et. al., 2016). This lengthy treatment and need for follow-up care means that many do not receive enough, or proper, care (Fernandes Penna et. al., 2014).

However, care for Hansen’s disease in Brazil has made strides in the last few decades. Beginning in the 1950s, Brazil moved away from policies of compulsory isolation in leprosaria to treat those infected, and instead integrated them into the the general healthcare system. Compulsory isolation was recognized as ineffective and expensive, as it commonly isolated those who had little risk of spreading the disease . In the 1970s, the disease was officially renamed Hansen’s disease, in an effort to destigmatize sufferers and lessen the association with “lepers” (Maciel et. al., 2003). The work on destigmatization was due to a burgeoning culture of activism, and these efforts paved the way for Brazil’s highly lauded HIV/AIDS public health program. In fact, the original federal task force on HIV was formed within the Division of Hansen's Disease and Sanitary Dermatology (Parker, 2003). Elimination of leprosy, in Brazil and worldwide, was stated in a joint resolution of WHO and the Pan-American Health Organization (PAHO) in 2016 (PAHO, 2017). This goal has not been reached, although the incidence of leprosy has dropped in recent years.

Related Articles

• Tuberculosis
• HIV/AIDS in Brazil: the Struggle for Affordable Anti-Retroviral Drugs
• HIV/AIDS in Brazil: Lessons for Policy

Additional Resources

WHO Global Leprosy Strategy

References

Clark, L. (2015). How armadillos can spread leprosy. Smithsonian Magazine. Retrieved from https://www.smithsonianmag.com/smart-news/how-armadillos-can-spread-leprosy-180954440/

Fernandes Penna, M. L., De Faria Grossi, M. A., & Oliveira Penna, G. (2013). Country Profile: Leprosy in Brazil. Leprosy Review, 84(4), 308–315.

Han X.Y., Silva F.J. (2014.) On the Age of Leprosy. PLOS Neglected Tropical Diseases 8(2). e2544.

Hansen’s Disease (Leprosy). (2017). CDC. Retrieved from https://www.cdc.gov/leprosy/transmission/index.html

Leprosy. (2019). NIH Genetics Home Reference. Retrieved from https://ghr.nlm.nih.gov/condition/leprosy#resources

Leprosy. (2019). WHO. Retrieved from https://www.who.int/news-room/fact-sheets/detail/leprosy

Leprosy in the Americas. (2017). PAHO. Retrieved from https://www.paho.org/hq/index.php?option=com_content&view=article&id=13657:lepra-en-americas&Itemid=40721&lang=en

Martins, R. J., Carloni, M. E., Moimaz, S. A., Garbin, C. A., & Garbin, A. J. (2016). Sociodemographic and epidemiological profile of leprosy patients in an endemic region in Brazil. Revista da Sociedade Brasileira de Medicina Tropical, 49(6), 777-780.

Parker, R. (2003). Building the foundations for the response to HIV/AIDS in Brazil: the development of HIV/AIDS policy, 1982-1996. Divulgação em Saúde para Debate, 27, 143-183.

Penna, M. L., Wand-Del-Rey-de-Oliveira, M. L., & Penna, G. (2009)(a). The epidemiological behavior of leprosy in Brazil. Leprosy Review 80, 332– 344.

Penna, M. L., Wand-Del-Rey-de-Oliveira, M. L., & Penna, G. (2009)(b). Spatial distribution of leprosy in the Amazon region of Brazil. Emerging infectious diseases, 15(4), 650–652.