A study by a team of researchers from Nagoya University (Japan) has shed new light on the relationship between human behavior and the evolution of SARS-CoV-2, the virus that causes Covid-19. The findings, published in Nature Communications, reveal that confinements and isolation measures can impact the emergence of new strains of the virus.
As with any living organism, viruses evolve over time. Those with survival advantages become dominant. Many environmental factors influence this evolution, including human behavior. By isolating sick people and implementing lockdowns to control outbreaks, humans can alter the evolution of the virus in different ways. Understanding these changes is crucial for developing adaptive treatments and interventions.
One important concept in this interaction is viral load, which refers to the amount or concentration of a virus present per ml of a body fluid. This is critical because a higher viral load in respiratory secretions increases the risk of transmission through droplets. Viral load relates to the potential to transmit a virus to other people.
The research group, led by Professor Shingo Iwami, used mathematical models with an artificial intelligence component to analyze previously published clinical data. They discovered that SARS-CoV-2 variants that were most successful in spreading had an earlier and higher peak in viral load. Additionally, they found that reduced incubation periods and increased proportions of asymptomatic infections affected the evolution of the virus as it mutated from Wuhan strain to Delta strain.
Iwami and his colleagues suggest that human behavioral changes designed to limit transmission may have increased selection pressure on SARS-CoV-2, leading it to be transmitted primarily during asymptomatic and pre-symptomatic periods, which occur earlier in its infectious cycle. As a result, peak viral loads advanced to this period for more effective spread during early pre-symptomatic stages.
The study raises questions about how new coronavirus strains may have evolved due to complex interactions between clinical symptoms and human behavior. It suggests that when evaluating public health strategies for Covid-19 or any potentially pandemic-causing pathogen in the future, it’s important to consider how changes in human behavior may influence virus evolution patterns.
In conclusion, this study provides valuable insights into how human behaviors can impact disease progression and evolution patterns of infectious agents like SARS-CoV-2. It highlights the importance of considering multiple factors when developing public health strategies aimed at controlling pandemics like COVID 19 or preventing their spread in future outbreaks.