The poliomyelitis virus is an enterovirus that enters through the mouth and multiplies in the throat and epithelial cells of the gastrointestinal tract. It will then move to the bloodstream and is carried to the central nervous system. Once in the CNS, the virus will attach to a host cell by binding with a cell surface receptor. The host cell surface receptor is a glycoprotein that has been recently identified as CD155. Once the virus has bound to the host cell, it will penetrate the host cell membrane and begin the replication of its genome. Many cells contain the surface receptor CD155; however, manifestation of this disease does not occur in all cells. The reason for incidence of the disease in only certain areas of the brain such as the brainstem is unknown. Once areas of the brain have been invaded by the virus, inflammation will occur. During inflammation, the brain’s tissues become swollen due to the body’s immune system response to the infection. Fluid, white blood cells, dead cellular debris and inactivated viruses resulting from the actions of the immune response can significantly alter the fluid surrounding healthy neurons. The function of these healthy neurons can decline due to disruptions in the cell membrane affecting electrical properties of the neuron or by interfering with the blood supply causing anoxic cellular damage. Depending on which neurons are damaged will result in a variety of different symptoms.
Polioencephalitis
Powassan encephalitis
Viral encephalitis
La Crosse encephalitis
Autoimmune encephalitis
Viliuisk encephalomyelitis
Eastern equine encephalitis
Japanese encephalitis