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Human parechoviruses--biology and clinical significance
G Stanway1, P Joki-Korpela, T Hyypiä
1Department of Biological Sciences, University of Essex, Colchester CO4 3SQ, UK.
Abstract:
A new genus of the family Picornaviridae, Parechovirus, has recently been recognised on the basis of distinctive biological and molecular properties. In particular: parechoviruses exhibit characteristic effects on the host cell; cleavage of the capsid protein VP0, required for maturation of the virus particle in most other picornaviruses, does not occur; there is a unique extension, which is highly basic in character, to the N-terminus of the capsid protein VP3; and the 2A protein, in common with those of only two other known picornaviruses, is a homologue of a family of cellular proteins involved in the control of cell proliferation. The type member of the Parechovirus genus is a frequent human pathogen, formerly known as echovirus 22, which has been renamed human parechovirus 1. The genus also includes the closely related virus, human parechovirus 2 (formerly echovirus 23). Human parechoviruses generally cause mild, gastrointestinal or respiratory illness, but more serious consequences of infection, such as myocarditis and encephalitis have been reported. Most infections occur in young children. Ljungan virus, a newly identified virus of rodents, shares a number of molecular features with the human parechoviruses, raising important questions about the evolution of parechoviruses and their introduction into the human population.
Insights
A new virus genus, Parechovirus, has been identified with unique molecular features. These human parechoviruses (HPVs) cause mild illnesses, but serious infections like myocarditis and encephalitis can occur, particularly in young children.
Area of Science:
- Virology
- Molecular Biology
- Infectious Diseases
Background:
- Picornaviridae family viruses share common characteristics.
- Parechoviruses exhibit distinct biological and molecular properties compared to other picornaviruses.
- The Parechovirus genus includes human parechovirus 1 (formerly echovirus 22) and human parechovirus 2 (formerly echovirus 23).
Purpose of the Study:
- To describe the newly recognized genus Parechovirus.
- To highlight the unique molecular and biological characteristics of parechoviruses.
- To discuss the clinical significance and evolutionary aspects of human parechoviruses.
Main Methods:
- Comparative analysis of viral properties.
- Identification of unique protein structures (VP0, VP3, 2A).
- Review of clinical manifestations and epidemiological data.
Main Results:
- Parechoviruses lack VP0 cleavage for maturation.
- A unique, basic N-terminal extension is present on capsid protein VP3.
- The 2A protein is homologous to cellular proteins controlling cell proliferation.
- Human parechoviruses commonly cause mild gastrointestinal or respiratory illness.
- Severe outcomes include myocarditis and encephalitis, especially in young children.
- Ljungan virus, a rodent virus, shares features with human parechoviruses.
Conclusions:
- Parechoviruses represent a distinct genus within the Picornaviridae family.
- Human parechoviruses are significant pathogens, particularly in pediatric populations.
- The molecular distinctions of parechoviruses have implications for understanding viral evolution and host interactions.