Coxsackievirus B5 is a member of the Enterovirus B species and one of six serotypes that make up the group B coxsackieviruses. This positive-sense, single-stranded RNA virus is non-enveloped with a small icosahedral capsid and is widespread.
Structure and replication
Coxsackievirus B5 shares the hallmark features of Enterovirus B: a non‑enveloped virion about 30 nm in diameter containing a positive-sense RNA genome of roughly 7.4 kb. The single open reading frame encodes a polyprotein that is cleaved into structural and non‑structural proteins. The virus enters host cells by binding the coxsackievirus–adenovirus receptor or related receptors on epithelial and myocardial cells; after uncoating, its RNA functions directly as messenger RNA. Translation is initiated via a 5′ internal ribosomal entry site, and replication occurs entirely in the cytoplasm. New virions assemble in association with the endoplasmic reticulum and are released when the host cell undergoes lysis. Transmission of CVB5 occurs primarily through the faecal–oral route, with respiratory droplets and contaminated surfaces also playing a role. The virus is acid stable and can survive in the gastrointestinal tract and on fomites, contributing to its global circulation. Most infections are subclinical; however, CVB5 is recognised as a common cause of viral myocarditis and sporadic cardiomyopathy, particularly in infants. Epidemiologic studies indicate that CVB5 is among the most prevalent CVB serotypes, yet infections are often unnoticed because they do not produce notable symptoms. Despite this, outbreaks of more severe disease have been documented. In China, investigations of hand, foot and mouth disease outbreaks detected CVB5 infection in a minority of patients; among those infected, many exhibited neurologic disease and aseptic meningitis. No specific antiviral therapy exists for CVB5 infection; management is supportive, and preventive strategies focus on sanitation, hand hygiene and isolation of infected individuals during symptomatic periods.
Outbreaks and clinical manifestations
In most cases CVB5 infection presents with mild febrile illness, sore throat and gastrointestinal discomfort. When the heart is involved, patients may experience chest pain, arrhythmias or signs of heart failure consistent with myocarditis. CVB5 has been implicated in encephalomyocarditis syndrome of neonates, aseptic meningitis and, rarely, acute flaccid paralysis. During an outbreak of hand, foot and mouth disease in Shandong Province, researchers found CVB5 infection in 14 children; 11 of these patients displayed neurologic complications and meningitis. Reports from surveillance in the United States show that approximately half of CVB5 detections occur in young infants. Because enteroviruses are shed in stool for weeks, strict hand washing after changing diapers and disinfecting commonly touched surfaces are essential to curb transmission.
Coxsackievirus B5 is a ubiquitous enterovirus that typically causes mild or asymptomatic infections. Nonetheless, its association with myocarditis, aseptic meningitis and severe hand, foot and mouth disease underscores the importance of surveillance and prevention. Effective hygiene and support remain the best strategies against CVB5.
Related Terms: Coxsackievirus B4, Coxsackievirus B6, Coxsackievirus B3, Enterovirus B, Poliovirus 3