Pathophysiology of Enterovirus All enteroviruses are mainly transmitted by feco-oral route except enterovirus 70 and coxsackievirus A21 which are transmitted by tears and respiratory secretions respectively. Once the virus enters into the oropharynx it makes its way into the submucosal tissue in the alimentary tract and distal pharynx. In the submucosal tissue, it undergoes replication. During replication, virus undergoes immense mutation. Interestingly, viral shedding begins before the onset of symptoms. Enteroviruses shed in feces and upper respiratory tract droplets. During the incubation period, which extends from 3-10 days, the virus spreads to regional lymph nodes. There too it undergoes replication. At this stage, minor viremia occurs. Minor viremia is associated with onset of symptoms and spread to spleen, bone marrow and liver. After entering the organs, major viremia occurs. The organs for major viremia include CNS and skin. In the 1-3 week virus sheds in upper respiratory tract droplets while in 3-8 weeks, the virus sheds in feces.