Hantavirus in East Asia

East Asia bears the highest global burden of Hemorrhagic Fever with Renal Syndrome (HFRS), with China reporting 20,000–50,000 cases annually, accounting for approximately 90% of the world's HFRS cases. Hantaan virus, carried by the striped field mouse (Apodemus agrarius), causes severe HFRS with case fatality rates of 5–15% in untreated populations. Seoul virus, harbored by the brown rat (Rattus norvegicus), produces a milder urban form of HFRS found throughout Chinese cities. Rice farming constitutes the primary occupational risk factor in rural China, where field preparation and harvest activities bring agricultural workers into direct contact with infected rodent excreta. The disease shows a bimodal seasonal distribution with peaks in November–January (linked to autumn harvest) and May–July (linked to spring planting). The Korean Peninsula, where HFRS was first characterized among UN troops in the 1950s, continues to report cases primarily among military personnel and rural workers. China has implemented large-scale bivalent inactivated hantavirus vaccines since the 1990s, with over 2 million doses administered annually in high-risk provinces. These vaccination programs, combined with rodent control and improved rural housing, have contributed to a substantial decline in incidence from peak levels in the 1980s. However, the disease remains a significant public health concern in endemic provinces including Heilongjiang, Shaanxi, and Shandong.