SARS-CoV-2 Omicron (B.1.1.529) infection in rhesus macaques, hamsters, and BALB/c mice with severe lung...

Area of Science:

• Virology
• Pathology
• Infectious Diseases

Background:

• The SARS-CoV-2 Omicron variant (B.1.1.529) is a rapidly spreading global health concern.
• Its pathological mechanisms and disease progression remain largely uncharacterized.
• Mutations, particularly in the spike protein, contribute to variant transmissibility and immune evasion.

Purpose of the Study:

• To investigate the pathogenesis of the SARS-CoV-2 Omicron variant (B.1.1.529) in distinct animal models.
• To compare viral loads and tissue tropism of Omicron infection across species.
• To identify suitable animal models for evaluating Omicron-specific therapeutics and vaccines.

Main Methods:

• Utilized rhesus macaques, hamsters, and BALB/C mice as experimental models.
• Inoculated animals with the Omicron (B.1.1.529) variant.
• Assessed viral loads in respiratory and extrapulmonary organs.
• Evaluated histopathological damage and inflammatory responses in infected tissues.

Main Results:

• Omicron (B.1.1.529) exhibited higher viral loads in the nasal turbinates, tracheae, bronchi, and lungs of hamsters and BALB/C mice compared to rhesus macaques.
• Severe histopathological damage and significant inflammatory responses were observed in the lungs of infected hamsters and mice.
• Viral replication was detected in multiple extrapulmonary organs in the studied animal models.

Conclusions:

• Hamsters and BALB/C mice demonstrate susceptibility to Omicron (B.1.1.529) infection with pronounced pulmonary pathology.
• These species serve as appropriate animal models for studying Omicron pathogenesis.
• The findings support the use of hamsters and BALB/C mice in preclinical research for developing drugs, vaccines, and therapies against the Omicron variant.