Enteric cytopathogenic human orphan viruses (echoviruses) are a group of related enteroviruses (family: Picornaviridae; genus Enterovirus B) commonly found in the human gastro-intestinal tract. Despite early experiments showing that these viruses could damage certain human cells in tissue culture experiments, they were initially not linked with any significant disease state. However, this view changed when echoviruses were later frequently isolated from patients suffering from a range of serious human diseases including aseptic meningitis, encephalitis and Guillain–Barré syndrome. While there is clear evidence that echovirus infection can result in several significant types of disease, this is still considered rare. Given the frequency at which people are infected with these viruses, the current view is that human infection is typically asymptomatic or subclinical, and only in a small proportion of people does it present as severe disease.

At present, 28 distinct serotypes of echovirus are recognised (echovirus 1-34; echoviruses 8, 10, 22, 23, 28 and 34 have been reclassified as other viruses based on modern analysis). While these viruses are genetically similar, there is wide variation in clinical presentation, distribution, and prevalence. In fact, patients linked to the same outbreak cluster can present with markedly different symptoms, making echoviruses an enigmatic collection of human pathogenic viruses. The absence of consistent clinical indicators provides challenges for both diagnosis and epidemiological assessments, and the triggers for development of severe disease are currently poorly understood.

At present, NCPV has 28 isolates available from 12 different echoviruses in the collection (echoviruses 3, 4, 6, 7, 9, 11, 13, 14, 16, 18, 25 and 30). We are keen to support researchers looking to further our understanding and ability to detect and understand these pathogens, and from anyone willing to deposit additional serotypes into the collection.

Further reading

T. Hyypiä (2008), Echoviruses, Encyclopedia of Virology (Third Edition), Academic Press, 65-71.

Rotbart (1995), Enteroviral infections of the central nervous system, Clin. Infect. Dis. Off. Publ. Infect. Dis. Soc. Am. 20, 971–981

Krishna et al. (2001), Echovirus Type 13 --- United States, 2001, MMWR. 50(36);777-780

Written by Barry atkinson, January 2021