Portal of entry of poliovirus in mainly:

Ans. is 'a' i.e., GITPathogenesis of poliomyelitis:On entering the body, the virus infects and multiplies in the tonsils and Peyer's patch of the ileum. It then spreads to regional lymph nodes and enters the blood, causing a primary viremia. On continued infection and multiplication of virus in the reticuloendothelial cells, it invades the blood stream again and causes secondary viremia. During this period of viremia. the poliovirus crosses the blood-brain barrier or gains access to the brain by infecting skeletal muscle and travelling up on the nerves to the brain as in rabies virus.