Epidemiology and Pathogenicity of Coxsackieviruses

The general properties and behaviour of coxsackieviruses (CV) have been the subject of recent reviews [1–3]. These members of the Enterovirus (EV) genus (Table 1) within the picornavirus family were originally discovered and then distinguished from polioviruses, and from the other EV found in later years, by their pathogenicity for suckling mice. Group A CV typically produce lethal, paralysing infections in newborn mice with severe, generalised myositis of skeletal muscles. Those classified in group B produce only scattered, focal myositis but more severe damage to the nervous system, brown fat, pancreas and other viscera — including the heart to a variable extent. The distinction from other viruses of the EV group became less absolute when later experience showed that a) most group B (CVB) a few group A CV (CVA) can be grown in the same types of cell cultures used for the cultivation of polioviruses and echoviruses; b) paralytic poliomyelitis can sometimes be caused by group B CV, by certain CVA (notably type A7), rarely by some echoviruses and also by the type 71 EV discovered later; c) acute muscle disease (Bornholm disease; epidemic pleurodynia) is mainly caused by CVB, sometimes by CVA, but occasionally by echoviruses (especially type 6); d) skin rash and oropharyngeal lesions can be caused by many CVA and CVB (especially types A4, A9, A16) and echoviruses (especially type 9); e) all types of EV can cause acute, mainly upper respiratory infections; f) the pathogenic properties for newborn mice of both CVA and CVB show considerable overlap and a few echoviruses can also cause myositis, notably type 9 (also known as CV type A23) and strains of type 6 [4]. Roberts and Boyd [5] have recently described their histopathological experience with routine diagnostic isolations in suckling mice from clinical specimens. Table 2 is based on their findings and shows a wide range of changes in newborn mice inoculated with materials containing typed EV. The effects of CV, especially those of group B, were much more severe than those of echoviruses and showed major impact on brown fat, nervous system, the heart and pancreas. Because of this overlap of properties between different groups of EV, recently discovered types have not been distinguished in the same way but are classified as higher-numbered “enteroviruses” (Table 1).