Circovirus

A genus of viruses in the family Circoviridae

Circovirus is a genus of viruses in the family Circoviridae. These viruses are characterized by their small, circular, single-stranded DNA genomes. Circoviruses are known to infect a variety of animal species, including birds and pigs, and are associated with several diseases.

Structure

Circoviruses are among the smallest viruses known, with a genome size of approximately 1.7 to 2.0 kilobases. The virions are non-enveloped and have an icosahedral symmetry. The capsid is composed of a single type of protein, which forms a protective shell around the viral DNA.

Genome

The genome of circoviruses is circular and single-stranded. It encodes for two major proteins: the replication-associated protein (Rep) and the capsid protein (Cap). The Rep protein is involved in the replication of the viral genome, while the Cap protein forms the structural component of the virus.

Replication

Circoviruses replicate in the nucleus of the host cell. The replication process involves the conversion of the single-stranded DNA genome into a double-stranded DNA intermediate, which serves as a template for the synthesis of new viral genomes. The replication cycle is dependent on the host cell's machinery.

Pathogenesis

Circoviruses are associated with several diseases in animals. In pigs, porcine circovirus type 2 (PCV2) is linked to postweaning multisystemic wasting syndrome (PMWS), a condition characterized by weight loss, respiratory distress, and immune suppression. In birds, circoviruses can cause beak and feather disease in parrots and other avian species.

Transmission

Circoviruses are transmitted through direct contact with infected animals or through contaminated environments. The viruses are stable in the environment, which facilitates their spread among susceptible hosts.

Prevention and Control

Control of circovirus infections involves good management practices, biosecurity measures, and vaccination. Vaccines are available for some circoviruses, such as PCV2 in pigs, which help reduce the incidence and severity of disease.

Related pages

• Virus
• DNA virus
• Viral replication
• Porcine circovirus