New Research Develops Vital Animal Model of SARS-CoV-2
The Importance of Reliable Animal Models in COVID-19 Research
The creation of effective therapies for COVID-19 is a major global concern. A crucial step in developing new treatments is establishing a dependable animal model to assess treatment efficacy prior to human trials. Since SARS-CoV-2 was identified only in the past year, a reliable animal model representing the key features of its infection has yet to be developed. This gap poses a challenge to the advancement of new COVID-19 therapies.
Recent Study on Macaques
A new study published in The Journal of Infectious Diseases addresses this issue by utilizing non-human primates, specifically macaques, to create a reliable animal model for future drug testing. The research involved 16 macaques, selected to represent two different subspecies, with a mix of male and female animals of varying ages. The macaques were infected with SARS-CoV-2 through multiple routes, including direct injection into the bloodstream, eyes, nose, mouth, and trachea.
Observations and Findings
Post-infection, researchers monitored the disease progression in the macaques. Swabs were collected from various sites at multiple time points after infection. The animals’ activity levels, body weight, respiratory rate, and body temperature were also tracked. Notably, while no significant changes in respiratory rate or weight were recorded, 13 out of the 16 macaques showed an increase in body temperature.
Lung tissue samples were examined three days after infection. These samples revealed signs of interstitial pneumonia and endothelitis (inflammation in blood vessels), reflecting the effects of COVID-19 on human lung tissue. Additionally, a reduction in total lymphocytes, particularly CD4+ and CD8+ T-cells, was observed in the macaques. This decrease mirrors the lymphocyte loss noted in approximately 83.2% of human patients hospitalized with COVID-19, highlighting another critical aspect of SARS-CoV-2 infection.
Implications for Future Research
The study’s findings indicate that both subspecies of macaques are susceptible to the SARS-CoV-2 strains currently affecting humans, and the virus’s impact on these animals closely resembles that seen in human lungs. This similarity suggests that macaques could serve as a suitable animal model for predicting disease progression and assessing the potential effects of new treatments. Moreover, the observed immune response changes in the animals imply that they may also be valuable for exploring the interactions between the virus and host immune systems.
Conclusion
While the results are encouraging, they do not offer an immediate solution to the ongoing COVID-19 crisis. Despite recent advancements in vaccination, there remains a pressing need for effective therapies. Establishing a reliable animal model is a significant step toward enhancing future drug development efforts.
Reference
Koo B-S, Oh H, Kim G, Hwang E-H, Jung H, Lee Y, et al. Transient Lymphopenia and Interstitial Pneumonia With Endotheliitis in SARS-CoV-2–Infected Macaques. The Journal of Infectious Diseases. 2020;222(10):1596-600.