LGI1 and viral encephalitis: The annual incidence per million person years has been estimated at 8.9 for PNSs in Northeastern Italy, 5 for antibody-positive AE in Olmsted County, MN, 0.83 for leucine-rich glioma inactivated 1 (LGI1) encephalitis in the Netherlands, and 0.9 to 2.2 for paediatric N-methyl-D-aspartic acid (NMDAr) encephalitis in the United Kingdom and Hong Kong.