Aetiology of vaginal discharge, urethral discharge, and genital ulcer in sub-Saharan Africa: A systematic review and meta-regression

PLoS Med. 2024 May 20;21(5):e1004385. doi: 10.1371/journal.pmed.1004385. eCollection 2024 May.


Background: Syndromic management is widely used to treat symptomatic sexually transmitted infections in settings without aetiologic diagnostics. However, underlying aetiologies and consequent treatment suitability are uncertain without regular assessment. This systematic review estimated the distribution, trends, and determinants of aetiologies for vaginal discharge, urethral discharge, and genital ulcer in sub-Saharan Africa (SSA).

Methods and findings: We searched Embase, MEDLINE, Global Health, Web of Science, and grey literature from inception until December 20, 2023, for observational studies reporting aetiologic diagnoses among symptomatic populations in SSA. We adjusted observations for diagnostic test performance, used generalised linear mixed-effects meta-regressions to generate estimates, and critically appraised studies using an adapted Joanna Briggs Institute checklist. Of 4,418 identified records, 206 reports were included from 190 studies in 32 countries conducted between 1969 and 2022. In 2015, estimated primary aetiologies for vaginal discharge were candidiasis (69.4% [95% confidence interval (CI): 44.3% to 86.6%], n = 50), bacterial vaginosis (50.0% [95% CI: 32.3% to 67.8%], n = 39), chlamydia (16.2% [95% CI: 8.6% to 28.5%], n = 50), and trichomoniasis (12.9% [95% CI: 7.7% to 20.7%], n = 80); for urethral discharge were gonorrhoea (77.1% [95% CI: 68.1% to 84.1%], n = 68) and chlamydia (21.9% [95% CI: 15.4% to 30.3%], n = 48); and for genital ulcer were herpes simplex virus type 2 (HSV-2) (48.3% [95% CI: 32.9% to 64.1%], n = 47) and syphilis (9.3% [95% CI: 6.4% to 13.4%], n = 117). Temporal variation was substantial, particularly for genital ulcer where HSV-2 replaced chancroid as the primary cause. Aetiologic distributions for each symptom were largely the same across regions and population strata, despite HIV status and age being significantly associated with several infection diagnoses. Limitations of the review include the absence of studies in 16 of 48 SSA countries, substantial heterogeneity in study observations, and impeded assessment of this variability due to incomplete or inconsistent reporting across studies.

Conclusions: In our study, syndrome aetiologies in SSA aligned with World Health Organization guidelines without strong evidence of geographic or demographic variation, supporting broad guideline applicability. Temporal changes underscore the importance of regular aetiologic re-assessment for effective syndromic management.

Prospero number: CRD42022348045.

Publication types

  • Systematic Review
  • Meta-Analysis

MeSH terms

  • Africa South of the Sahara / epidemiology
  • Chlamydia Infections / complications
  • Chlamydia Infections / diagnosis
  • Chlamydia Infections / epidemiology
  • Female
  • Genital Diseases, Female / epidemiology
  • Humans
  • Sexually Transmitted Diseases / diagnosis
  • Sexually Transmitted Diseases / epidemiology
  • Ulcer* / epidemiology
  • Urethral Diseases / epidemiology
  • Urethral Diseases / etiology
  • Vaginal Discharge* / epidemiology
  • Vaginal Discharge* / etiology
  • Vaginosis, Bacterial / complications
  • Vaginosis, Bacterial / diagnosis
  • Vaginosis, Bacterial / epidemiology

Grants and funding

JM acknowledges funding from the Imperial College President’s PhD Fund. JWI-E acknowledges funding from the Bill & Melinda Gates Foundation (INV-006733, INV-002606). JM, MKW, OE, AC, M-CB, and JWI-E acknowledge funding from the MRC Centre for Global Infectious Disease Analysis (reference MR/R015600/1), jointly funded by the UK Medical Research Council (MRC) and the UK Foreign, Commonwealth & Development Office (FCDO), under the MRC/FCDO Concordat agreement and is also part of the EDCTP2 programme supported by the European Union. Under the grant conditions of UKRI and the Bill & Melinda Gates Foundation, a Creative Commons Attribution 4.0 Generic License (CC BY) has already been assigned to any Author Accepted Manuscript version arising from this submission. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.