Neurotropism of influenza A virus

Influenza A virus is a crucial zoonotic pathogen that is prevalent in diverse avian and mammalian species. With the widespread emergence of novel avian influenza viruses (AIVs), diseases in humans caused by these viruses have increased. Thus, AIVs have become a critical concern to public health. Apart from respiratory symptoms, neurological symptoms can also be caused by AIV infections. The neurotropism of AIV can cause serious illnesses; therefore, it is considered a key criterion in the prognosis of the disease. To summarize the neurotropism of influenza viruses, we review the related findings on neurotropism of human influenza virus and AIV in the following three aspects: the clinical features of influenza virus-associated encephalopathy, the mechanism by which influenza virus invades the central nervous system, and the molecular mechanism of neurotropism.