A(H1N2) viruses have emerged through multiple reassortment events involving avian, swine, and human influenza viruses. These reassortments have resulted in various genetic compositions of A(H1N2) viruses in swine populations globally. In humans, A(H1N2) viruses have arisen from the reassortment of human A(H1N1) and A(H3N2) strains, leading to the circulation of A(H1N2) viruses with specific genetic characteristics. Rare instances of direct cross-species transmission from swine to humans have been reported, with notable cases in Minnesota in 2012, where swine-origin A(H1N2)v viruses were detected in humans.
