Animal Models for the Study of SARS-CoV-2-Induced Respiratory Disease and Pathology

Abstract

Emergence of the betacoronavirus SARS-CoV-2 has resulted in a historic pandemic, with millions of deaths worldwide. An unprecedented effort has been made by the medical, scientific, and public health communities to rapidly develop and implement vaccines and therapeutics to prevent and reduce hospitalizations and deaths. Although SARS-CoV-2 infection can lead to disease in many organ systems, the respiratory system is its main target, with pneumonia and acute respiratory distress syndrome as the hallmark features of severe disease. The large number of patients who have contracted COVID-19 infections since 2019 has permitted a detailed characterization of the clinical and pathologic features of the disease in humans. However, continued progress in the development of effective preventatives and therapies requires a deeper understanding of the pathogenesis of infection. Studies using animal models are necessary to complement in vitro findings and human clinical data. Multiple animal species have been evaluated as potential models for studying the respiratory disease caused by SARSCoV-2 infection. Knowing the similarities and differences between animal and human responses to infection is critical for effective translation of animal data into human medicine. This review provides a detailed summary of the respiratory disease and associated pathology induced by SARS-CoV-2 infection in humans and compares them with the disease that develops in 3 commonly used models: NHP, hamsters, and mice. The effective use of animals to study SARS-CoV-2-induced respiratory disease will enhance our understanding of SARS-CoV-2 pathogenesis, allow the development of novel preventatives and therapeutics, and aid in the preparation for the next emerging virus with pandemic potential.

Figure 1.

Pathophysiology of SARS-CoV-2 infection in the lung. (A) Healthy, uninfected lung with efficient gas exchange between the alveolar lumen and capillary. (B) SARS-CoV-2–infected lung with increased inflammatory infiltrates and cytokine production, alveolar edema and hemorrhage, cellular necrosis and luminal debris, hyaline membrane formation, endothelial activation and damage leading to increased vascular permeability, and microvascular thromboses—all of which contribute to impaired gas exchange.

Figure 2.

Similarities to and differences from SARS-CoV-2–induced respiratory disease and pathology in animal models compared with humans. K18, K18-hACE2 transgenic mice; MA10, MA10 mice infected with mouse adapted SARS-CoV-2.