Overview of enterovirus infections

[Renato]

Enteroviruses, along with rhinoviruses (see Common Cold) and human parechoviruses, are picornaviruses (pico, or small, RNA viruses). Human parechoviruses types 1 and 2 were previously named echovirus 22 and 23 but have now been reclassified. All enteroviruses are antigenically heterogeneous and have wide geographic distribution.
Enteroviruses include

Coxsackieviruses A1 to A21, A24, and B1 to 6
Echoviruses (enteric cytopathic human orphan viruses) 1 to 7, 9, 11 to 21, 24 to 27, and 29 to 33
Enteroviruses 68 to 71, 73 to 91, and 100 to 101
Polioviruses types 1 to 3

Enteroviruses are shed in respiratory secretions and stool and sometimes are present in the blood and cerebrospinal fluid of infected patients. Infection is usually transmitted by direct contact with respiratory secretions or stool but can be transmitted by contaminated environmental sources (eg, water).
Enteroviral diseases or epidemics in the US are more common in summer and fall.
Infection transmitted by a mother during delivery can cause severe disseminated neonatal infection, which may include hepatitis or hepatic necrosis, meningoencephalitis, myocarditis, or a combination of these, and can lead to sepsis or death.
Intact humoral immunity and B-cell function are required for control of enteroviral disease. Severe enteroviral infections (often manifesting as a slowly progressive meningoencephalitis, dermatomyositis, and/or hepatitis) occur in patients with defects in B lymphocyte function such as X-linked agammaglobulinemia , but usually not in those with other immune deficiencies.