Seasonal variation among tuberculosis suspects in four countries

Area of Science:

• Public Health
• Epidemiology
• Infectious Disease Research

Background:

• Understanding seasonal trends in tuberculosis (TB) diagnosis is crucial for resource allocation and public health interventions.
• Previous research has suggested potential links between climate and infectious disease patterns, but country-specific data on TB diagnostic trends are limited.

Purpose of the Study:

• To analyze monthly and seasonal trends in tuberculosis suspects and sputum smear-positive cases.
• To investigate the relationship between seasonal variations and patient attendance at diagnostic laboratory services across four diverse countries.

Main Methods:

• Analysis of nationally representative tuberculosis laboratory registers from Moldova, Mongolia, Uganda, and Zimbabwe.
• Examination of monthly proportions of tuberculosis suspects and confirmed cases over a calendar year.
• Correlation of diagnostic trends with country-specific climatic variations.

Main Results:

• Out of 47,140 registered suspects, 13.4% were confirmed TB cases, with country-specific proportions ranging from 9% (Moldova) to 21% (Uganda).
• Mongolia exhibited the most pronounced seasonal variations in TB suspects and cases, correlating with its extreme continental climate.
• Demographic analysis indicated that female suspects were consistently older than female cases, and male suspects were generally older than male cases.

Conclusions:

• Seasonal factors significantly influence attendance at tuberculosis diagnostic laboratory services, with climate playing a notable role, as seen in the contrasting patterns between Mongolia and Uganda.
• A combination of external (environmental) and potentially endogenous (individual) factors likely determines the presentation of tuberculosis suspects and cases to healthcare facilities.