Introduction
Mycobacterium leprae, the bacteria that causes leprosy, is sometimes referred to as Hansen’s disease. Leprosy is a chronic infectious disease. It causes discolouration, numbness, and disfigurement by affecting the skin, nerves, and mucous membranes. Leprosy is a historical illness that has caused social isolation and marginalization for those who have it for millennia.
Epidemiology
Leprosy is a worldwide health issue, with numerous nations reporting new cases each year. The World Health Organization (WHO) reports that there were 202,037 new cases in 2020, with the bulk of illnesses occurring in Asia and Africa. Tropical and subtropical areas are home to a higher incidence of leprosy, which is facilitated by overpopulation, inadequate sanitation, and poverty.
Causative Agent
The organism that causes leprosy is called Mycobacterium leprae. This rod-shaped, acid-fast bacterium is spread by respiratory droplets or by coming into touch with the lesions of an infected individual.
Incubation Period
The incubation period of leprosy is typically long, ranging from 3 to 5 years, but can be as long as 20 years.
Reservoir
Humans are the primary reservoir of M. leprae, but armadillos and other animals can also carry the bacterium.
Reservoir Infection
Reservoir infection occurs when an individual comes into contact with an infected person or animal, allowing the bacterium to enter the body.
Mode of Transmission
Leprosy is transmitted through:
- Respiratory droplets (e.g., coughing, sneezing)
- Contact with an infected person’s lesions
- Contact with an infected armadillo or other animal
Period of Communicability
A person with leprosy can transmit the disease to others during the incubation period and before treatment.
Susceptibility and Resistance
Leprosy can afflict anyone, although certain individuals are more vulnerable than others because of low immune, poor nutrition, or hereditary reasons. Leprosy resistance is impacted by both environmental and genetic factors..
Standard Case Definition
A suspected case of leprosy is defined as a person with one or more of the following:
- Skin lesions or discoloration
- Numbness or tingling in the hands and feet
- Enlarged nerves
- Eye problems
A confirmed case is diagnosed through laboratory tests, including skin smears and biopsies.
Susceptibility Case
A susceptibility case is a person who has been in close contact with someone diagnosed with leprosy.
Confirmed Case
A confirmed case is a person diagnosed with leprosy through laboratory tests.
Clinical Manifestation
Leprosy can manifest in different forms, including:
- Tuberculoid leprosy (most common form)
- Lepromatous leprosy
- Borderline leprosy
- Indeterminate leprosy
Control, Prevention, and Treatment
Control and prevention measures include:
- Early detection and treatment
- Contact tracing and surveillance
- Chemoprophylaxis for close contacts
- Vaccination (under development)
Treatment involves a combination of antibiotics, usually rifampicin and clofazimine, for 6-12 months.