Cardiovirus

Cardiovirus is a genus in the family Picornaviridae. Members are non-enveloped, icosahedral RNA viruses with a positive-sense single-stranded genome. The genus includes several viruses that infect mammals, notably Theiler's murine encephalomyelitis virus (TMEV) and Encephalomyocarditis virus (EMCV); human-associated cardioviruses such as Saffold virus have also been described. Cardioviruses are studied as models of viral pathogenesis and immune interaction, and their taxonomy is based on genome organization, antigenicity, and host range.

Genomes are about 8.2 to 8.4 kilobases in length and encode a single polyprotein that is proteolytically processed into structural and nonstructural proteins. The genome is organized into a P1 region encoding the capsid proteins (VP1–VP4) and P2–P3 regions encoding nonstructural proteins, including a viral protease (3C) and an RNA-dependent RNA polymerase (3Dpol). A leader protein (L) at the N-terminus modulates host cell responses and helps counter interferon signaling.

Host range is broad in animals but most cardioviruses are studied in rodents. Theiler's murine encephalomyelitis virus causes a biphasic disease in mice, including acute meningitis and later demyelinating disease, while Encephalomyocarditis virus can infect a wide range of mammals and commonly causes myocarditis, pancreatitis, and reproductive problems in livestock. Human infection is rare and typically mild, but severe cases with myocarditis or encephalitis have been reported.

Diagnosis relies on molecular tests (RT-PCR) and serology; virus isolation in cell culture and sequencing are also used. Prevention is mainly by hygiene and biosecurity in animal settings; there are vaccines for certain animal hosts against EMCV in livestock in some regions. There is no widely used human vaccine. Research uses cardioviruses as models of viral pathogenesis, neuroinflammation, and demyelinating disease.