A new research study shows that human behavior, like lockdowns, influences the evolution of COVID-19, leading to strains that are more transmissible earlier in their lifecycle.
Using artificial intelligence technology and mathematical modeling, a research group led by Nagoya University has revealed that human behavior, such as lockdowns and isolation measures, affect the evolution of new strains of COVID-19. SARS-CoV-2, the virus that causes COVID-19, developed to become more transmissible earlier in its lifecycle. The researcher's findings, published today (November 21) in the scientific journal Nature Communications, provide new insights into the relationship between how people behave and disease-causing agents.
Virus Evolution and Human Impact
As with any other living organism, viruses evolve over time. Those with survival advantages become dominant in the gene pool. Many environmental factors influence this evolution, including human behavior. By isolating sick people and using lockdowns to control outbreaks, humans may alter virus evolution in complicated ways. Predicting how these changes occur is vital to develop adaptive treatments and interventions.
Viral Load and Transmission
An important concept in this interaction is viral load, which refers to the amount or concentration of a virus present per ml of a bodily fluid. In SARS-CoV-2, 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 others. For example, a virus like Ebola has an exceptionally high viral load, whereas the common cold has a low one. However, viruses must perform a careful balancing act, as increasing the maximum viral load can be advantageous, but an excessive viral load may cause individuals to become too sick to transmit the virus to others.
AI-Assisted Research Findings
The research group led by Professor Shingo Iwami at the Nagoya University Graduate School of Science identified trends using mathematical modeling with an artificial intelligence component to investigate previously published clinical data.
They found that the SARS-CoV-2 variants that were most successful at spreading had an earlier and higher peak in viral load. However, as the virus evolved from the pre-Alpha to the Delta variants, it had a shorter duration of infection.
The researchers also found that the decreased incubation period and the increased proportion of asymptomatic infections recorded as the virus mutated also affected virus evolution.
Evolution From Wuhan to Delta Strain
The results showed a clear difference. As the virus evolved from the Wuhan strain to the Delta strain, they found a 5-fold increase in the maximum viral load and a 1.5-fold increase in the number of days before the viral load peaked.
Human Behavior and Virus Evolution
Iwami and his colleagues suggest that human behavioral changes in response to the virus, designed to limit transmission, were increasing the selection pressure on the virus. This caused SARS-CoV-2 to be transmitted mainly during the asymptomatic and presymptomatic periods, which occur earlier in its infectious cycle. As a result, the viral load peak advanced to this period to spread more effectively in the earlier pre-symptomatic stages.
Public Health Strategies and Virus Evolution
When evaluating public health strategies in response to COVID-19 and any future potentially pandemic-causing pathogens, it is necessary to consider the impact of changes in human behavior on virus evolution patterns. "We expect that immune pressure from vaccinations and/or previous infections drives the evolution of SARS-CoV-2," Iwami said. "However, our study found that human behavior can also contribute to the virus's evolution in a more complicated manner, suggesting the need to reevaluate virus evolution."
Their study suggests the possibility that new strains of coronavirus evolved because of a complex interaction between clinical symptoms and human behavior. The group hopes that their research will speed up the establishment of testing regimes for adaptive treatment, effective screening, and isolation strategies.
Reference: "Isolation may select for earlier and higher peak viral load but shorter duration in SARS-CoV-2 evolution" by Junya Sunagawa, Hyeongki Park, Kwang Su Kim, Ryo Komorizono, Sooyoun Choi, Lucia Ramirez Torres, Joohyeon Woo, Yong Dam Jeong, William S. Hart, Robin N. Thompson, Kazuyuki Aihara, Shingo Iwami and Ryo Yamaguchi, 21 November 2023, Nature Communications.
DOI: 10.1038/s41467-023-43043-2
News
New Toothpaste Stops Gum Disease Without Harming Healthy Bacteria
Researchers have developed a targeted approach to combat periodontitis without disrupting the natural balance of the oral microbiome. The innovation could reshape how gum disease is treated while preserving beneficial bacteria. The human mouth [...]
Plastic Without End: Are We Polluting the Planet for Eternity?
The Kunming Montreal Global Biodiversity Framework calls for the elimination of plastic pollution by 2030. If that goal has been clearly set, why have meaningful measures that create real change still not been implemented? [...]
Scientists Rewire Natural Killer Cells To Attack Cancer Faster and Harder
Researchers tested new CAR designs in NK-92 cells and found the modified cells killed tumor cells more effectively, showing stronger anti-cancer activity. Researchers at the Ribeirão Preto Blood Center and the Center for Cell-Based [...]
New “Cellular” Target Could Transform How We Treat Alzheimer’s Disease
A new study from researchers highlights an unexpected player in Alzheimer’s disease: aging astrocytes. Senescent astrocytes have been identified as a major contributor to Alzheimer’s progression. The cells lose protective functions and fuel inflammation, particularly in [...]
Treating a Common Dental Infection… Effects That Extend Far Beyond the Mouth
Successful root canal treatment may help lower inflammation associated with heart disease and improve blood sugar and cholesterol levels. Treating an infected tooth with a successful root canal procedure may do more than relieve [...]
Microplastics found in prostate tumors in small study
In a new study, researchers found microplastics deep inside prostate cancer tumors, raising more questions about the role the ubiquitous pollutants play in public health. The findings — which come from a small study of 10 [...]
All blue-eyed people have this one thing in common
All Blue-Eyed People Have This One Thing In Common Blue Eyes Aren’t Random—Research Traces Them Back to One Prehistoric Human It sounds like a myth at first — something you’d hear in a folklore [...]
Scientists reveal how exercise protects the brain from Alzheimer’s
Researchers at UC San Francisco have identified a biological process that may explain why exercise sharpens thinking and memory. Their findings suggest that physical activity strengthens the brain's built in defense system, helping protect [...]
NanoMedical Brain/Cloud Interface – Explorations and Implications. A new book from Frank Boehm
New book from Frank Boehm, NanoappsMedical Inc Founder: This book explores the future hypothetical possibility that the cerebral cortex of the human brain might be seamlessly, safely, and securely connected with the Cloud via [...]
Deadly Pancreatic Cancer Found To “Wire Itself” Into the Body’s Nerves
A newly discovered link between pancreatic cancer and neural signaling reveals a promising drug target that slows tumor growth by blocking glutamate uptake. Pancreatic cancer is among the most deadly cancers, and scientists are [...]
This Simple Brain Exercise May Protect Against Dementia for 20 Years
A long-running study following thousands of older adults suggests that a relatively brief period of targeted brain training may have effects that last decades. Starting in the late 1990s, close to 3,000 older adults [...]
Scientists Crack a 50-Year Tissue Mystery With Major Cancer Implications
Researchers have resolved a 50-year-old scientific mystery by identifying the molecular mechanism that allows tissues to regenerate after severe damage. The discovery could help guide future treatments aimed at reducing the risk of cancer [...]
This New Blood Test Can Detect Cancer Before Tumors Appear
A new CRISPR-powered light sensor can detect the faintest whispers of cancer in a single drop of blood. Scientists have created an advanced light-based sensor capable of identifying extremely small amounts of cancer biomarkers [...]
Blindness Breakthrough? This Snail Regrows Eyes in 30 Days
A snail that regrows its eyes may hold the genetic clues to restoring human sight. Human eyes are intricate organs that cannot regrow once damaged. Surprisingly, they share key structural features with the eyes [...]
This Is Why the Same Virus Hits People So Differently
Scientists have mapped how genetics and life experiences leave lasting epigenetic marks on immune cells. The discovery helps explain why people respond so differently to the same infections and could lead to more personalized [...]
Rejuvenating neurons restores learning and memory in mice
EPFL scientists report that briefly switching on three “reprogramming” genes in a small set of memory-trace neurons restored memory in aged mice and in mouse models of Alzheimer’s disease to level of healthy young [...]
