Cardiovirus are a group of viruses within order Picornavirales, family Picornaviridae.

[1] There are currently six species in the genus:[citation needed] Cardiovirus A is composed of only one serotype, encephalomyocarditis virus (EMCV).

[6][7] Inside the capsid of the virus there is a single linear, positive single-stranded RNA.

A unique feature of this genus is the presence of the L* protein, 18kDa, that is made out of frame from the polyprotein and is present in the DA subgroup of TMEV.

[citation needed] In the case of Cardiovirus A, the virus can cause encephalitis and myocarditis, mostly in rodents, which are natural hosts.

The first infection of cardiovirus in humans was identified in 2007 in a stool sample of an infant that was experiencing fever of unknown origin.

[10] Diseases associated with cardioviruses include: myocarditis, encephalitis, multiple sclerosis, and type 1 diabetes.