A Korean team has observed the immune system reactions of macaques when they are infected with Covid-19, in order to better understand what is happening to us humans.
-1605669719.jpg "What macaques teach us about SARS-CoV-2")
- Macaques were infected with Covid-19 to observe the reactions of their immune system.
- The researchers noted serious lung damage but almost no damage to other organs.
Our distant cousins are perhaps our best allies in understanding Covid-19. Researchers from the National Center for Primate Research at the Korea Institute of Biosciences and Biotechnology sought to understand the mechanism of infection of SARS-CoV-2 in non-human primates. The results of their study were published on November 15, 2020 in the Journal of Infectious Diseases.
First signs after three days
For their study, the researchers relied on 16 male and female macaques between three and six years old, to whom they inoculated with SARS-CoV-2 taken from a Korean patient. The animals, selected for their state of health, were anesthetized before undergoing viral tests, blood samples as well as nasopharyngeal, oropharyngeal, connective tissue and rectal swabs.
Once infected, the researchers noticed a drop in activity in primates and a slight increase in temperature within three days. However, no changes in weight or heart rate were observed.
During this experiment, four macaques lost their lives. During autopsies, scientists found bright red multifocal lesions inside the lungs. As in some humans, the macaques who died of Covid-19 also had traces of acute pneumonia. Finally, endothelitis was observed in all animals.
Severe damage to the lungs but nothing on the other organs
At the swab level, viral RNA was higher in swabs from the upper respiratory tract and in connective tissue from the lungs. Likewise, the coronavirus antigen was present in the lungs, suggesting that this is the predominant site of the virus. Very low amounts of Covid-19 were found in the other organs and no trace of the virus was detected in the plasma. All macaques without exception showed a significant decrease in the total number of CD4+ and CD8+ T cells and NK cells before gradually recovering after a week.
According to the researchers, the decline in viral load detection over time may explain why some tests are considered false positives. For the research team, this new model could be used to study the interaction between SARS-CoV-2 and the immune system in future therapeutic strategies.
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