History of Leprosy in Timeline

By Popular Timelines Editorial Team · Updated: May 25, 2024

Leprosy, or Hansen's disease, is a chronic bacterial infection caused by Mycobacterium leprae or Mycobacterium lepromatosis. It primarily affects the nerves, skin, respiratory tract, and eyes. Nerve damage is a hallmark of leprosy, often leading to numbness, muscle weakness, and loss of sensation. This can result in injuries going unnoticed and potentially causing disabilities. Symptoms are slow to develop, ranging from one to twenty years or more. Early detection and treatment are crucial to prevent irreversible nerve damage and disability.

1915: Alice Ball Discovers Water-Soluble Chaulmoogra Oil Treatment

In 1915, Alice Ball, the first Black woman to graduate from the University of Hawai'i with a masters in chemistry, made a significant breakthrough by discovering a method to make chaulmoogra oil water-soluble, leading to improved treatments for Hansen's disease.

1941: Promin Trials at Carville

In 1941, a significant milestone occurred at Carville when 22 patients participated in trials for a new drug called promin. The results were remarkably positive, described as miraculous, marking a turning point in leprosy treatment. This breakthrough paved the way for the development of dapsone, an even more effective medication in combating leprosy.

1954: World Leprosy Day Established

World Leprosy Day was established in 1954 to raise awareness about leprosy and combat the stigma surrounding the disease.

1955: The National Leprosarium at Carville

In 1955, the National Leprosarium at Carville, Louisiana, served as the sole leprosy hospital in the mainland United States. Due to limited knowledge about leprosy transmission and prevalent stigma, patients from across the country were sent to Carville for isolation and treatment. The institution gained recognition for its pioneering work in reconstructive surgery for leprosy patients.

1981: WHO Recommends Multi-Drug Therapy for Leprosy

In a significant advancement in leprosy treatment, the World Health Organization recommended multi-drug therapy (MDT) in 1981, combining three antileprosy drugs for increased effectiveness.

1983: Leprosy Incidence Peak in the US

Leprosy incidence in the United States reached its highest point in 1983.

1983: Repeal of the Leprosy Act and Shift in India's Approach

The year 1983 marked a turning point in India's approach to leprosy as the government repealed the Leprosy Act of 1898, which had mandated the segregation of individuals with leprosy, and shifted its focus from surveillance to treatment with the National Leprosy Elimination Programme.

1994: Start of a Period of High Leprosy Cure Rate

The period from 1994 to 2014 marked a time when 16 million people worldwide were cured of leprosy.

1995: WHO Initiative Provides Free Multi-drug Therapy

Between 1995 and 1999, a WHO initiative, supported by the Nippon Foundation, provided free multi-drug therapy to all countries where leprosy was endemic.

1999: End of Initial WHO Initiative for Free Multi-drug Therapy

This year marked the end of the initial WHO initiative, supported by the Nippon Foundation, to provide free multi-drug therapy to all countries where leprosy was endemic.

2000: Slow Rise in Leprosy Cases

After a significant decline, the number of leprosy cases began to rise again slowly in 2000.

2000: WHO Extends Free Multi-drug Therapy Provision

The WHO extended its program offering free multi-drug therapy for leprosy in 2000.

2005: Genetic Tracing of Leprosy Origins

In 2005, geneticists used comparative genomics to trace the origins of leprosy back to East Africa or the Near East, suggesting its spread coincided with human migration patterns.

2005: WHO Extends Free Multi-drug Therapy Provision

The WHO extended its program offering free multi-drug therapy for leprosy in 2005.

2008: Discovery of M. Lepromatosis

In 2008, scientists identified a new mycobacterium, M. lepromatosis, as a cause of leprosy. This bacterium is clinically indistinguishable from M. leprae.

2009: Oldest Evidence of Leprosy Found in Skeletal Remains

Skeletal remains discovered in 2009 in India provided the oldest documented evidence of leprosy, dating back to the 2nd millennium BC.

2010: WHO Extends Free Multi-drug Therapy Provision

The WHO extended its program offering free multi-drug therapy for leprosy in 2010.

2014: End of a Period of High Leprosy Cure Rate

This year marked the end of a period from 1994 to 2014 when 16 million people worldwide were cured of leprosy.

October 2015: WHO and Novartis Extend Free Multi-Drug Therapy Provision

In October 2015, the WHO and Novartis, a pharmaceutical company, extended their agreement to provide free multi-drug therapy for leprosy to all endemic countries until the end of 2025, ensuring continued access to treatment.

2015: Majority of New Leprosy Cases Concentrated in 14 Countries

In 2015, 94% of new leprosy cases were reported in 14 countries, with India, Brazil, and Indonesia accounting for the highest numbers.

November 2016: Leprosy Discovered in Red Squirrels

In November 2016, scientists discovered that red squirrels in Great Britain carried leprosy.

2016: WHO Launches Global Leprosy Strategy

In 2016, the World Health Organization (WHO) launched the "Global Leprosy Strategy 2016–2020: Accelerating towards a leprosy-free world" with the goal of eliminating leprosy. The strategy aimed to reduce the proportion of leprosy patients to less than one case per 10,000 population. It emphasized integrating leprosy treatment into public health services, ensuring effective diagnosis and treatment, and improving access to information.

2017: LepVax Clinical Trials Begin

A new vaccine specifically designed for leprosy, called LepVax, entered clinical trials in 2017.

2017: Leprosy DNA Found in Pre-Norman Era Skull

Researchers found DNA from a strain of Mycobacterium leprae in a pre-Norman era skull excavated in Hoxne, Suffolk, in 2017. This strain closely resembled that found in modern red squirrels.

2017: Slight Increase in New Leprosy Cases Recorded

The year 2017 saw a slight increase in new leprosy cases compared to the year 2018, with slightly more than 208,619 cases recorded.

2018: WHO Recommendation on BCG Vaccine for Leprosy

In 2018, the WHO recommended the BCG vaccine for people living in countries with a high incidence of tuberculosis and those in close contact with individuals diagnosed with leprosy.

2018: Slight Decrease in New Leprosy Cases Recorded

The year 2018 saw a slight decrease in new leprosy cases compared to the previous year, with 208,619 new cases recorded.

2019: Decrease in New Leprosy Cases in India and Removal of Divorce Law

In 2019, India recorded a decrease in new leprosy cases, reporting 114,451 patients, representing 57% of global cases. Additionally, a law allowing divorce based on a spouse's leprosy diagnosis was abolished.

2020: Decline in Leprosy Disease Burden

By 2020, a 45% reduction in the global leprosy disease burden was achieved due to increased availability and use of multidrug therapy, highlighting the effectiveness of this treatment approach.

2020: Global Leprosy Cases Decrease Significantly

By 2020, the number of leprosy cases globally decreased to fewer than 200,000, a significant drop from 5.2 million cases in the 1980s.

2020: Leprosy Cases Reported in the US

In 2020, there were 159 reported cases of leprosy in the United States.

2020: Encouraging Results Reported for LepVax Trials

Initial results from the LepVax clinical trials, published in 2020, showed promising outcomes for the development of the first leprosy-specific vaccine.

2025: End Date for WHO and Novartis Free Multi-Drug Therapy Provision

As per the agreement between the WHO and Novartis, the provision of free multi-drug therapy for leprosy to all endemic countries is set to continue until the end of 2025.