Infectious Disease · Medical Literature
Neglected tropical diseases in conflict-related humanitarian emergency settings: a systematic review of the literature.
Abstract
Neglected tropical diseases (NTDs) are a group of 21 conditions affecting an estimated 1 billion people worldwide, causing significant mortality and morbidity. WHO has targeted their control, elimination or eradication by 2030, while highlighting that conflict and humanitarian emergencies are risks to achieving this. A systematic review of peer-reviewed literature was undertaken, using terms related to conflict-related humanitarian emergencies (CRHE), based on the Armed Conflict Location & Event Data Project codebook terms for defining emergencies and terms including all WHO-defined NTDs. After a two-stage screening process, 26 papers were included. Common challenges for NTD programmes in CRHE were healthcare access, infrastructure, population movement and data quality. Multisectoral collaboration between actors in conflict-settings was offered as a learning for NTD programmes, along with community participation and decentralisation. Evidence gaps were identified in the knowledge base for certain NTDs and in high-quality evidence for interventions in CRHE. Collaboration is a key area for focused improvement for NTD programmes in CRHE. This should be across sectors and extend to research and analysis approaches, to ensure the most effective interventions are identified and implemented and that NTD road map targets can be achieved.
Clinical relevance
What are the common challenges, programmatic lessons, and evidence gaps for neglected tropical disease (NTD) programmes operating within conflict-related humanitarian emergency settings? __SNAPSHOT__ {"studyDesign":"Systematic review of peer-reviewed literature (PRISMA-reported)","setting":"Global; multi-country conflict-affected and humanitarian emergency settings; affiliated institutions include the London School of Hygiene & Tropical Medicine (Clinical Research Department) and University of Liverpool (Institute of Infection, Veterinary & Ecological Sciences)","sampleSize":"26 peer-reviewed papers included after two-stage screening (from literature search conducted January 2005 – May 2024)","population":"Populations affected by conflict-related humanitarian emergencies (CRHE) with co-occurring neglected tropical diseases; geographic spread excludes the American region (no eligible studies identified)","intervention":"NTD control, elimination, or eradication programmes operating in CRHE settings (not an experimental intervention; descriptive and observational literature synthesized)","comparator":"Not applicable (no comparator group; review characterises challenges and strategies across observational and programmatic reports)","primaryOutcome":"Identification of common challenges, programmatic learnings, and evidence gaps for NTD programmes in conflict-related humanitarian emergencies","followUp":"Not reported (varied across included primary studies; search window: 2005–2024)","fundingSource":"No specific funding reported. One author (EMH-E) receives salary support from the International Trachoma Initiative, which receives operating and research funding from Pfizer Inc., manufacturers of azithromycin (Zithromax). Potential conflict of interest noted."}
Key findings
Across the 26 included papers, nine WHO-defined NTDs were represented. Cutaneous leishmaniasis was the most frequently studied NTD, appearing in eight papers. The four dominant programmatic challenges identified were: (1) healthcare access, (2) health infrastructure deterioration, (3) population movement and displacement, and (4) data quality. Regarding data quality specifically, poor population statistics, patchy surveillance coverage, unreliable clinical records, inconsistent case definitions used by parallel international organisations, and missing data due to security-restricted treatment site access were all cited across multiple included studies. Three principal programmatic learnings emerged: (a) multisectoral collaboration across humanitarian actors; (b) community participation; and (c) decentralisation of care, including the use of reporting networks with congruent case definitions and clinically trained community-level practitioners. Additional specific lessons included: rapid restoration of primary healthcare after conflict was associated with declining trends in some zoonotic NTDs (e.g., brucellosis); standardisation of therapy and consistent access to essential medicines were associated with reduced snakebite morbidity and mortality; and identification and targeted scale-up of interventions for high-risk groups were highlighted for trachoma prevention. Evidence gaps were identified both in the knowledge base for specific NTDs and in high-quality interventional evidence for CRHE settings. Of 26 included studies, 19 scored highly on JBI quality checklists (low risk of bias); nine had incomplete clinical and demographic reporting, often reflecting genuine data scarcity. Only one study was an interventional RCT, and it scored poorly on quality assessment due to methodological limitations including lack of blinding and failure to use intention-to-treat analysis. No quantitative meta-analysis was performed; no pooled effect sizes, confidence intervals, or p-values are reported.
Practice implications
This systematic review establishes that NTD programmes face a consistent and predictable set of structural challenges in CRHE settings—principally healthcare access, infrastructure disruption, population movement, and data unreliability—and identifies multisectoral collaboration, community participation, and decentralisation as the most widely endorsed programmatic responses. The findings apply broadly to populations in conflict-affected low- and middle-income country settings. However, the evidence base is heavily dominated by observational and descriptive studies; with only one RCT included and scoring poorly, the review cannot establish causal efficacy of any specific intervention. Several WHO-defined NTDs remain almost entirely unstudied in CRHE contexts, representing critical evidence gaps. Populations from the Americas, and non-English-language literature, were excluded by search design, limiting geographic generalisability. The role of one author's institutional tie to Pfizer-funded research (via the International Trachoma Initiative) should be considered when interpreting findings pertaining to trachoma-related interventions. Only the abstract and published summary were available for this structured review; full-text analysis of the complete 26-paper corpus would be required to further assess risk of bias and completeness of findings. __LIMITATIONS__ Near-complete absence of high-quality interventional evidence: only one RCT among 26 included papers, and it had significant methodological flaws (no blinding, no intention-to-treat analysis).,Search restricted to English-language publications (2005–2024), likely excluding substantial literature from high-NTD-burden regions including South America, the Caribbean, and non-Anglophone conflict zones.,No American-region studies were identified, limiting generalisability to conflict settings in Latin America and the Caribbean.,Nine of 26 included studies had incomplete clinical and demographic reporting, though often reflecting a true evidence gap in conflict settings rather than study-level methodological failure.,Heterogeneity across included papers (different NTDs, conflict types, geographies, and outcome measures) precludes quantitative synthesis or meta-analysis.,Several NTDs within the WHO list of 21 were not represented in any included paper, indicating critical knowledge gaps that may reflect underreporting or genuine absence of research.,Potential conflict of interest: one author receives salary support from an organisation funded by Pfizer Inc., which manufactures azithromycin, a primary treatment for trachoma.,Systematic review design captures existing literature rather than generating new primary evidence; programmatic recommendations are based on observational and experiential reports, not experimental evidence.,The abstract provided is truncated; full-text synthesis may reveal additional limitations, subgroup analyses, or nuances not captured here. __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ This systematic review of 26 papers is the first to comprehensively map NTD programme challenges and learnings across conflict-related humanitarian emergency settings, identifying healthcare access, infrastructure, population displacement, and data quality as the dominant barriers, with multisectoral collaboration, community participation, and decentralisation as key mitigation strategies. The evidence base is predominantly observational and of low interventional quality, with only one poor-quality RCT identified, meaning no specific intervention can be recommended on the basis of rigorous efficacy data. Clinicians and programme managers working in conflict settings should be aware of these structural challenges and advocate for standardised surveillance, cross-sector collaboration, and rapid primary care restoration, while recognising that high-quality interventional research in this area remains urgently needed.