Mycobacterium Tuberculosis, Herpes Simplex Virus Type 1 and Enterovirus in Clear Cerebrospinal Fluid Meningitis at Brazzaville University Hospital

Abstract

Introduction: Clear cerebrospinal fluid (CSF) meningitis represents a major public health problem in resource‑limited countries. It is characterized by
CSF pleocytosis with a macroscopically clear appearance, and its etiologies are mainly viral, tuberculous, or undetermined.

Objective: This study aimed to analyze clear CSF samples from a cytological and biochemical perspective, identify the main pathogens, and assess the diagnostic yield of examinations performed at the Brazzaville University Hospital laboratory.

Methods: An analytical cross‑sectional study with prospective data collection was conducted from April 1 to September 30, 2021, including all clear CSF samples received at the bacteriology‑virology‑immunology laboratory of CHU‑B. Analyses included cytology, biochemistry, and PCR detection of Mycobacterium tuberculosis, HSV‑1, and Enterovirus.

Results: The frequency of clear CSF meningitis was 48.6%. Patients under 5 years accounted for 67.9% of cases, with a slight male predominance (sex
ratio 1.03). Cytology showed a mean of 245 leukocytes/mm³, with lymphocytic predominance. Protein levels were elevated (2.02 g/L) in all cases, while hypoglycorrhachia was observed only in tuberculous meningitis. The pathogens identified were mainly Enterovirus (20.3%), followed by Mycobacterium tuberculosis (5.8%) and HSV‑1 (11.6%). A large proportion of cases (63.8%) remained of undetermined etiology. Diagnostic yield was higher among infants (<1 year, 53.6%) and young adults (20–40 years, 61.5%).

Conclusion: Clear CSF meningitis is frequent in Brazzaville, predominantly affecting young children. Cytological and biochemical CSF profiles were
consistent with the identified etiologies. Improving laboratory capacity, particularly through systematic integration of multiplex film array nucleic acid amplification tests, is essential to reduce the number of undetermined cases and strengthen diagnostic and therapeutic management.