Geographic Concentration of Genomic Surveillance for Highly Pathogenic Avian Influenza A(H5), South Asia, 2015–2025

Early detection of mammalian adaptation in highly pathogenic avian influenza A(H5) depends on genomic surveillance, yet its distribution across high-burden regions is poorly characterized. We quantified open-access (GenBank/INSDC) H5 genomic coverage relative to reported outbreak burden across nine South Asian countries during 2015–2025, linking isolates to FAO EMPRES-i/WOAH events. Of 919 H5 isolates, 814 (89%) came from one country (Bangladesh); the other eight contributed 105. India, with the largest burden (322 events), yielded only 42 isolates (13 per 100); Nepal, 2 of 78; Afghanistan, none of 5. Concentration was extreme (Gini 0.83) and unchanged by adding restricted GISAID records (1,297 combined isolates; Bangladesh 89%) or by normalizing to poultry or human population. Because reported outbreaks track reporting effort, these coverage ratios are directional, not rates. This single-country dependency, deepest where burden is highest, is a regional early-warning vulnerability.