Beta-CoV

Beta-CoV

Beta-CoV (Betacoronavirus) is one of the four genera of coronaviruses, which are enveloped, positive-sense, single-stranded RNA viruses. The Betacoronavirus genus is part of the Coronaviridae family and the Nidovirales order. This genus includes several notable viruses that infect humans and animals, including the viruses responsible for SARS, MERS, and COVID-19.

Classification

Betacoronaviruses are classified into four lineages:

• A lineage (Embecovirus): Includes the human coronavirus OC43 (HCoV-OC43) and bovine coronavirus (BCoV).
• B lineage (Sarbecovirus): Includes the severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2, the virus responsible for the COVID-19 pandemic.
• C lineage (Merbecovirus): Includes the Middle East respiratory syndrome coronavirus (MERS-CoV).
• D lineage (Nobecovirus): Primarily found in bats.

Structure

Betacoronaviruses have a characteristic crown-like appearance due to the spike (S) glycoproteins on their surface. The viral genome is approximately 26 to 32 kilobases in length, making it one of the largest among RNA viruses. The genome encodes several structural proteins, including:

• Spike (S) protein: Facilitates entry into host cells by binding to specific receptors.
• Envelope (E) protein: Involved in virus assembly and release.
• Membrane (M) protein: Plays a role in the shape and structure of the virus.
• Nucleocapsid (N) protein: Encapsulates the viral RNA genome.

Transmission and Pathogenesis

Betacoronaviruses are zoonotic, meaning they can be transmitted from animals to humans. They can also spread from person to person through respiratory droplets. The pathogenesis of these viruses involves the infection of the respiratory tract, leading to symptoms ranging from mild respiratory illness to severe pneumonia and acute respiratory distress syndrome (ARDS).

Notable Betacoronaviruses

• SARS-CoV: Emerged in 2002, causing severe acute respiratory syndrome (SARS) with a high mortality rate.
• MERS-CoV: Identified in 2012, causing Middle East respiratory syndrome (MERS) with a significant mortality rate.
• SARS-CoV-2: The causative agent of the COVID-19 pandemic, first identified in 2019.

Research and Vaccines

Research on Betacoronaviruses has accelerated due to the global impact of COVID-19. Vaccines targeting the spike protein of SARS-CoV-2 have been developed and deployed worldwide, significantly reducing the severity and spread of the disease.

Also see

• Coronaviridae
• SARS
• MERS
• COVID-19
• RNA virus