Coxsackievirus A6 is an enterovirus in species Enterovirus A that causes hand, foot and mouth disease and other exanthems. The virus has a non enveloped icosahedral capsid about 30 nm in diameter and a single stranded positive sense RNA genome. It replicates in the cytoplasm of human cells, infecting the oropharyngeal and intestinal mucosa, and spreads primarily through fecal–oral, respiratory and contact routes. Infections are common in young children but adults can also be affected. Disease is usually mild, with fever and vesicular lesions, but some outbreaks have been associated with more extensive skin involvement and nail shedding.
Structure, replication and epidemiology
Coxsackievirus A6 belongs to the Enterovirus A species within the Picornaviridae family. Like other coxsackieviruses, its genome encodes a single polyprotein that is proteolytically cleaved into structural proteins (VP1‑VP4) and non‑structural proteins required for replication. The virion is resistant to acid and temperature fluctuations, allowing survival in the environment. After oral or respiratory entry, the virus replicates in the mucosal epithelium of the throat and intestine, followed by transient viremia that seeds skin and sometimes nails. Coxsackievirus A6 has been identified worldwide and has emerged as a significant cause of hand, foot and mouth disease since the early 2010s. It circulates year‑round but peaks in summer and autumn, particularly in childcare settings where close contact facilitates transmission. Most patients recover without complications, though immunocompromised individuals may experience more severe disease. There are currently no specific antivirals or vaccines; management is supportive.
Notable outbreaks and clinical features
Coxsackievirus A6 infection presents with fever, sore throat and vesicles on the hands, feet and mouth similar to classic hand, foot and mouth disease. However, several outbreaks have noted more diffuse and severe rash, sometimes involving the trunk, extremities and perioral skin. During 2011–2012 outbreaks in the United States and Europe, clinicians reported cases with onychomadesis, where fingernails or toenails shed weeks after illness. Adults have also been affected, and lesions may be painful and bullous. Transmission occurs through saliva, respiratory droplets, vesicle fluid and feces, with an incubation period of three to six days. Good hand hygiene, cleaning of contaminated surfaces and avoiding close contact with infected individuals reduce spread. Coxsackievirus A6 is an emerging enterovirus that has expanded the clinical spectrum of hand, foot and mouth disease. Although most infections are self limited, clinicians should recognise its potential for atypical and widespread cutaneous manifestations and counsel patients on hygiene to prevent transmission. Related Terms: Coxsackievirus A10, Coxsackievirus A16, Enterovirus A71, Hand‑foot‑and‑mouth disease, Coxsackievirus B1