Anthropogenic environment and the burden of infectious gastrointestinal diseases in preschool children in Pacific Island countries, territories, and States: a narrative review

Infectious gastrointestinal diseases (I-GID) remain a major global burden among preschool children, influenced by the anthropogenic environment (AE) where children live and play. In Pacific Island Countries, Territories, and States (PICTS), remoteness, extreme climates, and resource constraints exacerbate AE conditions that facilitate I-GID transmission, but the actual burden and key AE risk factors remain unclear. This narrative review synthesised existing evidence on the I-GID burden and AE risk factors among preschool children in PICTS by searching four scientific databases, supplemented by grey literature. Reports were screened and graded by relevance to the review objectives (Highly relevant, Relevant, Low relevance, or Not relevant), with Not relevant reports excluded. We identified 48 reports from 12 PICTS published in 1972-2024; only six (12.5%) were highly relevant, and 15 (31.3%) were from Papua New Guinea. Thirty‑three (68.8%) described I-GID burden, but heterogeneous case definitions and metrics limited comparability, with estimates varying across settings and I-GID types. Twenty‑two (45.8%) examined AE risk factors, with preschool-specific evidence spanning physical environmental conditions and exposure-related behaviours, although findings for several commonly reported factors were inconsistent. Eight (16.7%) examined contextual factors, but none formally assessed whether these factors modified, mediated, or amplified AE-I-GID relationships. Overall, the evidence was limited and geographically uneven. I-GID burden among preschool children in PICTS, its AE risk factors, transmission pathways, and the role of contextual factors remain inadequately characterised. Integrated environmental, microbiological, epidemiological, and surveillance studies are needed to strengthen burden estimation, characterise transmission pathways, and identify priority AE and contextual risk factors for prevention and control.