Chile becomes second country to receive WHO verification for eliminating leprosy

 

• Chile became the first country in the Americas — and the second globally — to be officially verified as having eliminated leprosy disease.

• The verification by the World Health Organisation (WHO), together with the Pan American Health Organisation (PAHO), recognises more than three decades of sustained public health action, robust surveillance, long-term political commitment, and a health system that has remained vigilant even in the absence of local transmission.

• In September 2024, Jordan became the first country in the world to be officially verified as having eliminated leprosy. 

How Chile achieved this milestone?

• Leprosy (Hansen disease) was historically recorded in Chile at the end of the 19th century on Rapa Nui (Easter Island). 

• The disease was limited in mainland Chile, with sporadic introductions, contained through isolation and treatment measures in the Island, where the last secondary cases were managed by the late 1990s.

• Since then, Chile has not reported any locally acquired case of leprosy for more than 30 years, with the last locally acquired case detected in 1993. 

• However, the disease was never removed from the country’s public health agenda. It remained a notifiable condition, monitored through mandatory reporting, integrated surveillance, and continuous clinical readiness across the health system.

• At the request of Chile’s Ministry of Health, PAHO and WHO convened an independent expert panel in 2025 to assess whether elimination had been achieved and could be sustained over time.

• Its findings confirmed the absence of local transmission and validated Chile’s capacity to detect and respond to future cases occurring among the non-autochthonous population.

• Chile’s accomplishment paves the way for other nations, illustrating the impact of political will, cross-sector collaboration, and adaptive planning in low-incidence settings.

Leprosy

• Leprosy, also known as Hansen’s disease, is a chronic infectious disease caused by Mycobacterium leprae. 

• It primarily affects the skin, peripheral nerves, mucosal surfaces of the upper respiratory tract and eyes. 

• Leprosy is curable and treatment in the early stages can prevent disability.

• Left untreated, leprosy can cause permanent damage to the skin, nerves, limbs and eyes. 

• Leprosy is a neglected tropical disease (NTD) which still occurs in more than 120 countries. More than 200,000 new cases are reported every year.

Transmission

The disease is transmitted through droplets from the nose and mouth. Prolonged, close contact over months with someone with untreated leprosy is needed to catch the disease. The disease is not spread through casual contact with a person who has leprosy like shaking hands or hugging, sharing meals or sitting next to each other. Moreover, the patient stops transmitting the disease when they begin treatment.

Diagnosis

Leprosy is diagnosed by finding at least one of the following cardinal signs: 

i) Definite loss of sensation in a pale (hypopigmented) or reddish skin patch.

ii) Thickened or enlarged peripheral nerve, with loss of sensation and/or weakness of the muscles supplied by that nerve.

iii) Microscopic detection of bacilli in a slit-skin smear.

• The cases are classified into two types for treatment purposes: Paucibacillary (PB) case and Multibacillary (MB) case.

• PB case: A case of leprosy with one to five skin lesions, without demonstrated presence of bacilli in a skin smear.

• MB case: A case of leprosy with more than five skin lesions; or with nerve involvement (pure neuritis, or any number of skin lesions and neuritis); or with the demonstrated presence of bacilli in a slit-skin smear, irrespective of the number of skin lesions.

Treatment

The current recommended treatment regimen consists of three drugs: dapsone, rifampicin and clofazimine. The combination is referred to as multi-drug therapy (MDT). The duration of treatment is six months for PB and 12 months for MB cases. MDT kills the pathogen and cures the patient.