Singularity wrote:
Know how some families run to twin or multiple births on a genetic basis? And some just seem extra fertile for extra long? The delta branch of the C***D family propagates with both tendencies, like The Duggars, but on steroids.
Sorry not to edit and this clean up, but my eyes are bothering me. I couldn't get the copief link to go directly to the article....
Scientific American
PUBLIC HEALTH
How the Delta Variant Spreads So Quickly
V***l load is roughly 1,000 times higher in people infected with the Delta variant than those infected with the original c****av***s strain, according to a study in China
By Sara Reardon, Nature magazine on July 23, 2021
How the Delta Variant Spreads So Quickly
A health worker administers a dose of the C****-** v*****e in New Delhi, India, July 2021. Credit: Mayank Makhija Getty Images
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Since first appearing in India in late 2020, the Delta variant of SARS-CoV-2 has become the predominant strain in much of the world. Researchers might now know why Delta has been so successful: people infected with it produce far more v***s than do those infected with the original version of SARS-CoV-2, making it very easy to spread.
According to current estimates, the Delta variant could be more than twice as t***smissible as the original strain of SARS-CoV-2. To find out why, epidemiologist Jing Lu at the Guangdong Provincial Center for Disease Control and Prevention in Guangzhou, China, and his colleagues tracked 62 people who were quarantined after exposure to C****-** and who were some of the first people in mainland China to become infected with the Delta strain.
The team tested study participants’ ‘v***l load’ — a measure of the density of v***l particles in the body — every day throughout the course of infection to see how it changed over time. Researchers then compared participants’ infection patterns with those of 63 people who contracted the original SARS-CoV-2 strain in 2020.
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In a preprint posted 12 July, the researchers report that v***s was first detectable in people with the Delta variant four days after exposure,compared with an average of six days among people with the original strain, suggesting that Delta replicates much faster. Individuals infected with Delta also had v***l loads up to 1,260 times higher than those in people infected with the original strain.
The combination of a high number of v***ses and a short incubation period makes sense as an explanation for Delta’s heightened t***smissibility, says epidemiologist Benjamin Cowling at the University of Hong Kong. The sheer amount of v***s in the respiratory tract means that superspreading events are likely to infect even more people, and that people might begin spreading the v***s earlier after they become infected.
And the short incubation makes contact tracing more difficult in countries such as China, which systematically tracks each infected person’s contacts and require them to quarantine. “Putting it all together, Delta’s really difficult to stop,” Cowling says.
Genetics researcher Emma Hodcroft at the University of Bern in Switzerland agrees that the mechanism makes sense. She and Cowling both suspect that estimates of the exact difference in v***l load between Delta and the original strain are likely to shift as more scientists study the v***s in various populations.
A number of other questions about the Delta variant remain unanswered. It’s still unclear, for instance, whether it is more likely to cause severe disease than the original strain, and how good it is at evading the i****e s****m. Hodcroft expects some of this information will emerge as researchers look more closely at broader and more diverse populations of people infected with Delta and other variants. “This v***s has surprised us,” she says.
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This article is reproduced with permission and was first published on July 21 2021.
ABOUT THE AUTHOR(S)
Sara Reardon is a freelance journalist based in Bozeman, Mont. She is a former staff reporter at Nature, New Scientist and Science and has a master's degree in molecular biology."