Multibacillary leprosy by population groups in Brazil: Lessons from an observational study

Area of Science:

• Epidemiology
• Public Health
• Infectious Diseases

Background:

• Leprosy remains a significant public health issue in Brazil, with the country reporting the second-highest number of new cases globally.
• Multibacillary (MB) leprosy, caused by Mycobacterium leprae, is primarily spread by patients with this form of the disease.

Purpose of the Study:

• To identify specific population groups at higher risk for multibacillary (MB) leprosy in Brazil.
• To inform strategies for early diagnosis and effective control of leprosy transmission.

Main Methods:

• Analysis of a national databank of leprosy cases in Brazil from 2001 to 2013.
• Evaluation of epidemiological characteristics and factors associated with higher bacillary loads in MB leprosy patients.

Main Results:

• New case detection rates for MB leprosy increased with age, particularly in men, reaching 44.8/100,000 in the 65-69 age group.
• Men and individuals over 59 years old had double the odds of MB leprosy compared to females and younger individuals.
• Higher bacillary loads were observed in males and patients aged 20-59 compared to females and other age groups.
• While overall detection rates decreased, the proportion of MB cases and elderly patients increased between 2003 and 2013, suggesting reduced transmission.

Conclusions:

• Public health policies in Brazil must prioritize interventions targeting men and the elderly to further decrease Mycobacterium leprae transmission.
• Focusing on these at-risk demographics is crucial for advancing leprosy control efforts in endemic regions.