Systematic Review of Infectious Disease Risks and Evidence for Cross-Border Transmission at the China–Pakistan Border: A One Health Perspective

The China–Pakistan border connects Xinjiang and Gilgit-Baltistan through a high-altitude corridor where human mobility, animal movement, vector ecology, and variable diagnostic capacity may facilitate infectious-disease spread. We critically map a historically assembled set of 28 primary studies using three evidence levels: documented transboundary transmission (Level 1), border-associated epidemiological plausibility without demonstrated directionality (Level 2), and contextual One Health vulnerability (Level 3). The preserved historical screening summary reported 120 identified records, 92 title/abstract records, 36 full texts, and 28 included studies. Bibliographic verification and study-level JBI appraisal improved the traceability of the retained studies but did not re-execute the eligibility search. No included study established Level 1 transmission; five were classified as Level 2 and 23 as Level 3. Evidence was dominated by veterinary and vector investigations. Critically, database-specific original retrieval counts, search execution dates, Google Scholar stopping rules, and eight report-specific full-text exclusion reasons remain unavailable; the original search’s completeness cannot therefore be independently assessed. A new, fully logged multisource search, followed by duplicate screening and updated synthesis, is required to substantiate the designation of a reproducible systematic review. Until then, the findings should be regarded as a descriptive evidence map, not proof that relevant literature was comprehensively captured.