Aphthovirus

Aphthovirus is a genus of viruses in the family Picornaviridae. Viruses in this genus are known to cause diseases in cloven-hoofed animals, including cattle, sheep, and pigs. The most well-known virus in this genus is the Foot-and-mouth disease virus (FMDV), which causes a highly contagious and economically devastating disease in livestock.

Taxonomy

The genus Aphthovirus is one of the 29 genera in the family Picornaviridae. This family is part of the order Picornavirales, which includes small, non-enveloped, positive-sense single-stranded RNA viruses. The Aphthovirus genus includes seven serotypes: O, A, C, SAT 1, SAT 2, SAT 3, and Asia 1.

Structure and Genome

Aphthoviruses are non-enveloped viruses with icosahedral symmetry. The virion is approximately 30 nm in diameter. The genome is a single-stranded, positive-sense RNA molecule approximately 8.3-8.5 kilobases in length. It contains a single open reading frame that encodes a polyprotein, which is subsequently cleaved into individual viral proteins.

Replication

Replication of Aphthoviruses occurs in the cytoplasm of the host cell. The virus attaches to the host cell using a specific receptor, and the viral RNA is released into the cell. The RNA is translated into a polyprotein, which is then cleaved into individual proteins. These proteins include the viral capsid proteins and the non-structural proteins necessary for replication of the viral RNA.

Pathogenesis and Clinical Signs

The primary route of infection for Aphthoviruses is through the respiratory tract, although oral and skin routes are also possible. The virus replicates in the pharyngeal epithelium and then spreads to other tissues, including the heart and skeletal muscle. Clinical signs of infection can include fever, lameness, vesicles in the mouth and on the feet, and in severe cases, death.

Control and Prevention

Control of Aphthovirus infections primarily involves quarantine and slaughter of infected animals. Vaccination is also used, particularly in regions where the virus is endemic. However, due to the high mutation rate of the virus, vaccines must be regularly updated to match circulating strains.

See Also

• Picornaviridae
• Foot-and-mouth disease virus
• Viral replication
• Viral pathogenesis