Leprosy

Leprosy is a chronic infectious disease caused by Mycobacterium leprae. The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract and also the eyes. Leprosy is curable and treatment provided in the early stages averts disability. Multidrug therapy (MDT) treatment has been made available by WHO free of charge to all patients worldwide since 1995, and provides a simple yet highly effective cure for all types of leprosy.

Leprosy Facts

  • Official figures show that 214 783 new cases of leprosy were reported during 2016. Globally, the number of new cases detected annually has remained stable, at around 220,000, in recent years.
  • M. leprae multiplies very slowly and the incubation period of the disease is about five years. Symptoms can take as long as 20 years to appear.
  • Leprosy is not highly infectious. It is transmitted via droplets, from the nose and mouth, during close and frequent contacts with untreated cases.
  • Untreated, leprosy can cause progressive and permanent damage to the skin, nerves, limbs and eyes.
  • Early diagnosis and treatment with multidrug therapy (MDT) remain the key elements in eliminating the disease as a public health concern.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae, an acid-fast, rod-shaped bacillus. The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract and also the eyes.

Leprosy is curable and treatment provided in the early stages averts disability.

Multidrug therapy (MDT) treatment has been made available by WHO free of charge to all patients worldwide since 1995, and provides a simple yet highly effective cure for all types of leprosy.

Leprosy today

Leprosy control has improved significantly due to national and subnational campaigns in most endemic countries. Integration of primary leprosy services into existing general health services has made diagnosis and treatment of the disease easy. In April 2016, the WHO launched a five-year global leprosy strategy in partnership with national programmes and all other stakeholders of leprosy control. Since control strategies are limited, national programmes actively improve case holding, contact tracing, monitoring, referrals and record management.

According to official reports received from 143 countries the number of cases detected during 2016 was 214 783 compared with 210 740  in 2015.

Pockets of high endemicity still remain in some areas of Brazil, Indonesia, Philippines, Democratic Republic of Congo, India, Madagascar, Mozambique, Nepal, and the United Republic of Tanzania. All endemic countries remain highly committed to eliminating the disease, and continue to intensify their leprosy control activities.

There are currently 22 global priority countries as stated by the WHO. Within these global priority countries, there were 214 783 new cases of leprosy in 2016. Most new cases can be found in India, Brazil and Indonesia, accounting for 81% of new cases in 2015.

Brief history - disease and treatment

Leprosy was recognized in the ancient civilizations of China, Egypt and India. The first known written mention of leprosy is dated 600 BC. Throughout history, the afflicted have often been ostracized by their communities and families.

Although leprosy was treated differently in the past, the first breakthrough occurred in the 1940s with the development of the drug dapsone, which arrested the disease. But the duration of the treatment was many years, even a lifetime, making it difficult for patients to follow. In the 1960s, M. leprae started to develop resistance to dapsone, the world’s only known anti-leprosy drug at that time. In the early 1960s, rifampicin and clofazimine, the other two components of recommended multidrug therapy (MDT), were discovered.

In 1981, a WHO Study Group recommended MDT. MDT consists of 3 drugs: dapsone, rifampicin and clofazimine and this drug combination kills the pathogen and cures the patient.

Since 1995, WHO provides free MDT for all patients in the world, initially through the drug fund provided by the Nippon Foundation and since 2000, through the MDT donation provided by Novartis and the Novartis Foundation for Sustainable Development.

Elimination of leprosy as a public health problem

In 1991 WHO's governing body, the World Health Assembly (WHA) passed a resolution to eliminate leprosy by the year 2000. Elimination of leprosy is defined as a prevalence rate of less than 1 case per 10 000 persons. The target was achieved on time and the widespread use of MDT reduced the disease burden dramatically.

  • Over the past 20 years, more than 14 million leprosy patients have been cured, with over 4 million since 2000.
  • The prevalence rate of the disease has dropped from more than 5 million cases in the mid-1980s to less than 200 000 cases at the end of 2016. 
  • Dramatic decrease in the global disease burden: from 5.2 million in 1985 to 805 000 in 1995 to 210 758 in 2015
  • Leprosy has been eliminated from 119 countries out of 122 countries where the disease was considered as a public health problem in 1985.
  • So far, there has been no resistance to antileprosy treatment when used as MDT.
  • Efforts currently focus on eliminating leprosy at a national level in the remaining endemic countries and at a sub-national level from the others. The WHO launched The Global Leprosy Strategy to acheive 1) a reduction to zero caes of new Grade 2 Disability child cases; 2) a reduction in the rae of new Grade 2 Disability cases to less than 1 case per million population and 3) zero counties with laws or legislation that allow discrimination against leprosy by 2020.

Actions and resources required

In order to reach all patients, leprosy treatment needs to be fully integrated into general health services. Moreover, political commitment needs to be sustained in countries where leprosy remains a public health problem. Partners in leprosy elimination also need to continue to ensure that human and financial resources are available.

The age-old stigma associated with the disease remains an obstacle to self-reporting and early treatment. The image of leprosy has to be changed at the global, national and local levels. A new environment, in which patients will not hesitate to come forward for diagnosis and treatment at any health facility, must be created.