The word Leprosy comes from an ancient Greek terminology meaning “a disease that makes the skin scaly”. Leprosy is a bacterial infection caused by the bacillus Mycobacterium leprae. It is a slowly progressing infection as it takes a long time for the bacteria to multiply in the body. The average incubation period (the time it takes for symptoms to appear following the exposure) of the disease, could be as long as five years and it may range between one year and longer than 20 years. Leprosy is transmitted via respiratory droplets, during close and frequent contact with untreated cases. Untreated, leprosy can cause progressive and permanent damage to the skin, nerves, limbs, and eyes. World Leprosy Day is celebrated annually on the last Sunday of the month of January with the aim of raising awareness on the disease and stopping the stigma and discrimination. This year the campaign slogan is announced as “Unity for dignity”, to call for unity in securing the dignity of the people who have been affected with the disease. Consultant Dermatologist Dr. Indira Kahawita, attached to the Anti-Leprosy Campaign of the Ministry of Health shared her expertise about the disease. Excerpts from the discussion are as follows;  History of leprosy The documented history of leprosy dates back to 700 BCE, before the birth of the Gautama Buddha and the earliest record of leprosy and its treatment is seen in the Mahavamsa, the great chronicle of Sri Lanka. As documented, two ancestors of the Gautama Buddha contracted the disease and lived in the wilds until they were cured using some herbal medicines. Following the 17th Century, Norway, Iceland, and England had been the countries in Europe where leprosy was a significant problem. In 1854, Norway appointed a medical superintendent for leprosy and a national registry of leprosy infected individuals was established in 1856. This is recorded as the world’s first national patient register. In 1873, bacillus Mycobacterium leprae was identified as the causative agent for the disease by a Norwegian scientist named Gerhard-Henrik Armauer Hansen and the disease was also called Hansen’s disease after this discovery.  Global statistics According to official figures from 139 countries of the six World Health Organisation (WHO) regions, there had been 127,558 new leprosy cases detected globally in 2020. This includes 8,629 children below 15 years. The new case detection rate among the child population was recorded at 4.4 per million child population. At the end of the year 2020, the prevalence was 129,389 cases on treatment and the prevalence rate corresponds to 16.7 per million population. Covid-19 pandemic has disrupted implementation of the control programme globally and a 37% reduction in new case detection was observed in 2020 compared with 2019. Situation in Sri Lanka Annually, an average of 2,000 new leprosy patients are identified in Sri Lanka and approximately 40% of these patients are from the Western Province and the percentage of child cases are about 10% on average. The new case detection rate among the child population is approximately 8 per million child population. Although a slow declining trend is seen over the last ten years, fluctuations are observed. During the past two years of Covid-19 pandemic, a significant decline in the number of cases was observed. However, this is apparently an artificial decline as the public interest towards other diseases was significantly impaired. This is of a serious concern as the patients who have missed the diagnosis and delaying treatment can end up with disabilities. How to diagnose?  The disease mainly affects the skin, nerves, and mucous membranes. It initially manifests as  discoloured patches of skin (lighter than the surrounding skin) that may also be numb. As the disease progresses, the number of patches will increase and they may appear as nodules. Due to the numbness, there can be painless ulcers on feet. When the disease progresses further, disfiguring of the face with appearance of thickening in the facial skin, nodules in earlobes, and loss of eyebrows or eyelashes may appear. The cardinal signs for the diagnosis of leprosy are, definite loss of sensation in a hypo-pigmented or reddish skin patch, a thickened or enlarged peripheral nerve, with loss of sensation and or weakness of the muscles supplied by the nerve and the presence of acid fast bacilli in a slit skin smear. There should be at least one cardinal sign to diagnose leprosy. Leprosy patients can be classified into two groups, with slightly different signs and symptoms:

• Paucibacillary (PB), or tuberculoid, leprosy is characterised by one to five number of hypopigmented or hyperpigmented skin patches that exhibit loss of sensation due to infection of the peripheral nerves supplying the region. Thickening of a single nerve can be seen and there will be only a few numbers of bacteria.
• Multibacillary (MB) leprosy is characterised by more than five skin patches and thickening of more than one nerve can be seen. Large number of bacilli will be identified in smears.

Treatment of leprosy  Leprosy was managed with herbals and natural remedies in the past, until the development of the medicine dapsone in 1940. The duration of treatment lasted many years, often a lifetime, making compliance of the patients extremely difficult. In the 1960s, M. leprae started to develop resistance to dapsone, the only known anti-leprosy medicine at that time. In the early 1960s, rifampicin and clofazimine were discovered and these medicines were subsequently added to the treatment regimen, which was later labelled as multidrug therapy (MDT). With successful results, the WHO recommended MDT for treatment of leprosy in 1981. Hence, the currently recommended MDT regimen consists of three antibiotics; dapsone, rifampicin, and clofazimine. This treatment lasts six months for paucibacillary and 12 months for multibacillary cases. MDT kills the pathogen and cures the patient completely. Since 1981, WHO has provided MDT free of cost with the assistance of donor agencies. Globally, over 16 million leprosy patients have been treated with MDT over the past 20 years and a general reduction in new cases, though gradual, is observed in several countries. The Anti-Leprosy Campaign of Sri Lanka The construction of Leprosy Asylum was funded by the famous Dutch East India Company called VOC (Vereenigde Oost-Indische Compagnie). Construction of the Leper Asylum at Hendala was completed in 1708 under Dutch Governor Hendrick Becker and it still exists today as the Hendala Government Leprosy Hospital. This asylum is probably the first of this kind in the East. As the British took control of the coastal provinces of the country, the administration of the leprosy asylum came under the British military until 1858, where the British started the Civil Medical Department and the asylum administration was undertaken by the Civil Medical Department in 1868. As the Lepers Ordinance established in 1901 by the British government, segregation of leprosy patients was made compulsory. A second leprosy asylum was set up on the island of Mantivu off the eastern coast of the country in 1920. At present, it is under the local health authority in the Eastern Province. In the 1930s, the Medical and Sanitary Services Director initiated leprosy surveillance in the country to measure the magnitude of the spread of the disease and the very first surveillance was conducted during 1931. The Anti-Leprosy Campaign (ALC) was established as a vertical programme under the Department of Health Services in 1954, with the assistance of WHO. In 1983 MDT was introduced to the country and compulsory admission of the patients was discontinued. ALC was decentralised in 1989 and maintained a supervisory role. In 2001, leprosy control activities were integrated into the General Health Services. After that all health institutions of Sri Lanka were provided with adequate stock of MDT blister packs. At present, almost all cases of leprosy are being managed at skin clinics under the supervision of consultant dermatologists. All districts of Sri Lanka are served by at least one skin clinic, hence leprosy care services are available islandwide. In addition, the Central Leprosy Clinic, located at room 12, Outpatient Department (OPD) of National Hospital of Sri Lanka, Colombo, functions as a walk-in clinic for suspected leprosy patients. The clinic functions on all weekdays and Saturdays. Sri Lanka achieved the status of elimination of leprosy as a public health problem (prevalence < 1 per 10,000 population) at the national level in 1995. Day-to-day management, recording, and reporting of leprosy patients became the responsibility of general public health staff as for any other health conditions. Currently, the ALC is responsible for all leprosy-related activities in Sri Lanka including diagnosis, management, rehabilitation, and control activities.  Message to the public Dr. Kahawita shared her message for the World Leprosy Day, to raise awareness about this forgotten disease: “Leprosy is still prevalent in Sri Lanka, and can affect persons from all walks of life. Leprosy is curable without any long-lasting effects if diagnosed and treated early. There was a decline in the number of detected cases in 2020 and 2021, probably due to the disruption of healthcare services with the Covid-19 pandemic. There may be patients who are having signs and symptoms of leprosy but not coming forward for treatment. As leprosy is a disease leading to nerve damage and deformity, early treatment is essential. Otherwise the nerve damage may become irreversible and lead to permanent deformities. In addition, untreated patients may spread the disease within the society. A patient who is on treatment as advised cannot transmit the disease. Therefore, we urge anyone who has suspicious features of leprosy to seek treatment as soon as possible at the closest skin clinic or at the Central Leprosy Clinic.”