68) Mycobacterium leprae: Clinical Findings, Diagnosis, Treatment, Epidemiology, Prevention and Control.

Question 1

Mycobacterium leprae: clinical findings

Answer 1

Mycobacterium leprae causes leprosy (Hansen’s disease), which primarily affects the skin, peripheral nerves, upper respiratory tract, and eyes. Clinical manifestations depend on the immune response and can be classified into two main types: lepromatous leprosy and tuberculoid leprosy. Lepromatous leprosy presents with numerous, symmetric skin lesions, thickened nerves, and loss of sensation. Tuberculoid leprosy presents with localized, well-defined skin lesions, often with nerve involvement, and a positive response to the tuberculin test. In some cases, it can lead to severe deformities, such as claw hand or foot drop.

Question 2

Mycobacterium leprae: diagnosis

Answer 2

Diagnosis of leprosy is primarily clinical, based on characteristic skin lesions and nerve involvement. Skin biopsy may show the presence of acid-fast bacilli (AFB) in the lesions. Other diagnostic tests include the slit-skin smear, where material is taken from skin lesions to search for AFB, and PCR testing to detect M. leprae DNA. The skin test with lepromin can help differentiate between the two forms of leprosy, with a positive response indicating tuberculoid leprosy and a negative response indicating lepromatous leprosy.

Question 3

Mycobacterium leprae: treatment

Answer 3

The treatment of leprosy involves a multi-drug regimen, which includes dapsone, rifampin, and clofazimine. The World Health Organization (WHO) recommends a 6-12 month course for multibacillary leprosy and a 6-month course for paucibacillary leprosy. The goal of treatment is to eliminate the bacteria, prevent disability, and reduce transmission. Drug resistance, especially to dapsone, can complicate treatment. Neurological complications, such as nerve damage, may require additional symptomatic treatment and rehabilitation.

Question 4

Mycobacterium leprae: epidemiology

Answer 4

Leprosy is a chronic infectious disease caused by M. leprae, which has a long incubation period of 2–10 years. The disease is most common in tropical and subtropical regions, including parts of India, Brazil, and Southeast Asia. Although leprosy incidence has declined globally, it remains endemic in certain areas, especially in rural communities. M. leprae is transmitted via prolonged close contact with untreated individuals, though it is not highly contagious. The exact mode of transmission is not fully understood, but nasal droplets are believed to play a role.

Question 5

Mycobacterium leprae: prevention and control

Answer 5

Prevention of leprosy focuses on early diagnosis and treatment to prevent transmission. Chemoprophylaxis with single-dose rifampin has been used in contacts of individuals with leprosy to prevent new cases. The World Health Organization provides free multi-drug therapy (MDT) to all patients worldwide, which has led to a significant reduction in the burden of disease. Public health strategies also include health education and community awareness to reduce stigma associated with leprosy and ensure early detection and treatment.