Molecular Diagnosis of Incident Tuberculosis in Patients Attending Clinics in Health Districts of the Central African Republic

Abstract

Introduction : Tuberculosis remains a major cause of morbidity, with infection affecting more than one-third of the world’s population, and mortality. The risk of transmission of pulmonary tuberculosis is determined by the presence of new cases. In The Central African Republic (CAR), the incidence of tuberculosis was first documented in 2014. The objective of this study was to determine the incidence of tuberculosis based on molecular screening carried out in the country’s health districts. Methodology : This was a descriptive cross-sectional study conducted at the National Laboratory of Clinical Biology and Public Health in Bangui over a six-month period from January to June 2025. The study sample consisted of patients screened for tuberculosis in thirty-two health districts during this period. Patients currently undergoing anti-tuberculosis treatment were excluded to ensure that the focus was on incident cases. The biological samples collected were analyzed using GeneXpert, a semi-quantitative automated test based on real-time amplification of Mycobacterium tuberculosis complex DNA and rifampicin resistance. This molecular biology technique enables rapid detection of Mycobacterium tuberculosis complex DNA. The data collected were entered into Excel and analyzed using Epi Info 7. Results : A total of 12,112 patients aged between 4 months and 100 years were registered in 32 of the 35 districts in the CAR. The median age was 35 ± 18 years and the most common age was 40 years. The male-to-female ratio was 1.8. The most represented age group was 15 to 49 years old, with a rate of 62.23%. The overall incidence of tuberculosis was 45.50 per 100,000 person-months. The highest incidence was found in June (10.67 per 100,000 person-months), among patients aged ≥ 50 years (323.50/100,000 person-semesters), men (57.99/100,000 person-months), and those in Bangui District 1 (319/100,000 person-months). Pulmonary tuberculosis was the most common location among cases (93.22%). High bacterial load (27.32%) and low bacterial load (25.29%) were more prevalent. Male gender (p = 0.0004) and place of residence (p < 0.0001) were significantly associated with the occurrence of tuberculosis. Advanced age provided a significant level of protection (ORa = 0.67 and p < 0.0001). Pulmonary localization accounted for 93.22% of tuberculosis cases. The other localizations were extrapulmonary (6.78%). Male gender (p = 0.0004, ORa = 1.30 [1.12 - 1.52]) and place of residence (p < 0.0001) were the variables significantly associated with the occurrence of tuberculosis. Conclusion : Tuberculosis remains a major public health problem in the CAR due to its morbidity. New cases of pulmonary tuberculosis, which are a source of new infections, are not insignificant. There is a need to focus on prevention through awareness-raising.