Orthopoxvirus

Orthopoxvirus

Structure of the Orthopoxvirus

The Orthopoxvirus is a genus of viruses in the family Poxviridae, subfamily Chordopoxvirinae. This genus includes several notable viruses that infect both humans and animals, including the Variola virus, which causes smallpox, and the Vaccinia virus, which is used in the smallpox vaccine.

Structure

Orthopoxviruses are large, brick-shaped viruses with a complex structure. They have a linear double-stranded DNA genome, which is approximately 130-300 kilobases in length. The viral particle is enveloped and contains a core that houses the viral DNA and associated proteins. The surface of the virus is covered with tubules and filaments, giving it a distinctive appearance under the electron microscope.

Replication Cycle

Replication cycle of Poxviridae

Orthopoxviruses replicate in the cytoplasm of the host cell, which is unusual for DNA viruses. The replication cycle begins with the attachment of the virus to the host cell surface, followed by entry into the cell. Once inside, the virus uncoats and releases its DNA into the cytoplasm. The viral DNA is then transcribed and translated by the host's machinery, leading to the production of viral proteins and assembly of new viral particles. The newly formed viruses are released from the host cell to infect other cells.

Pathogenesis

Orthopoxviruses can cause a range of diseases in humans and animals. The most infamous member of this genus is the Variola virus, the causative agent of smallpox, a disease that has been eradicated through vaccination. Other members, such as the Monkeypox virus and Cowpox virus, can cause zoonotic infections in humans, often resulting in mild to severe illness.

Prevention and Control

Vaccination is the primary method of prevention for orthopoxvirus infections. The smallpox vaccine, which uses the Vaccinia virus, provides cross-protection against other orthopoxviruses. In the event of an outbreak, isolation of infected individuals and vaccination of contacts are critical measures to control the spread of the virus.

Related Pages

• Poxviridae
• Smallpox
• Vaccinia virus
• Monkeypox