Coxsackievirus

Coxsackievirus is a member of the enterovirus genus within the Picornaviridae family — small, non-enveloped viruses with a positive-sense, single-stranded RNA genome. Like other enteroviruses, it spreads primarily by the fecal-oral route, with respiratory droplet transmission also possible, and infections peak in summer and early fall.

Coxsackieviruses are divided into two groups with characteristic disease patterns. Group A viruses classically cause hand-foot-and-mouth disease — fever with vesicular lesions on the palms, soles, and oral mucosa, most often in young children — and herpangina, which features painful vesicles and ulcers on the posterior oropharynx. Group B viruses are associated with myocarditis and pericarditis, dilated cardiomyopathy as a sequela, and pleurodynia (Bornholm disease), a syndrome of sharp, spasmodic chest and abdominal muscle pain.

Both groups can cause aseptic (viral) meningitis, and enteroviruses as a class are among its most common causes. Most coxsackievirus infections are mild and self-limited, but the group B cardiac manifestations make it a clinically important virus — coxsackievirus B is a leading viral cause of myocarditis.

Coxsackievirus is high-yield virology on the USMLE Step 1 exam. Know its picornavirus classification and RNA genome, the A-versus-B disease associations, and the classic clinical vignettes: a toddler with mouth and palm vesicles, or a young adult with chest pain and elevated cardiac enzymes after a viral illness.