Area of Research: The Microbial Environment
Paper comparing epidemics of COVID and suppression in many countries & regions published by Burg & Ausubel
Nations and regions which implemented interventions sufficient to block community spread effectively experienced a rapid decline in confirmed cases. However, with lifting of interventions, rates rebounded to the previous high infection rates and attained a relatively stable empirical steady state. For COVID-19, societies so far appear to face a choice between relatively high oscillations involving waves of suppression and infection and lesser oscillations around an endemic setpoint.
Trajectories of COVID-19: A longitudinal analysis of many nations and subnational regions David Burg, Jesse H. Ausubel published 23 Jun 2023 PLOS ONE https://doi.org/10.1371/journal.pone.0281224
Trajectories of COVID-19: A longitudinal analysis of many nations and subnational regions
Abstract: The COVID-19 pandemic is the first to be rapidly and sequentially measured by nation-wide PCR community testing for the presence of the viral RNA at a global scale. We take advantage of the novel “natural experiment” where diverse nations and major subnational regions implemented various policies including social distancing and vaccination at different times with different levels of stringency and adherence. Initially, case numbers expand exponentially with doubling times of ~1–2 weeks. In the nations where interventions were not implemented or perhaps lees effectual, case numbers increased exponentially but then stabilized around 102-to-103 new infections (per km2 built-up area per day). Dynamics under effective interventions were perturbed and infections decayed to low levels. They rebounded concomitantly with the lifting of social distancing policies or pharmaceutical efficacy decline, converging on a stable equilibrium setpoint. Here we deploy a mathematical model which captures this V-shape behavior, incorporating a direct measure of intervention efficacy. Importantly, it allows the derivation of a maximal estimate for the basic reproductive number Ro (mean 1.6–1.8). We were able to test this approach by comparing the approximated “herd immunity” to the vaccination coverage observed that corresponded to rapid declines in community infections during 2021. The estimates reported here agree with the observed phenomena. Moreover, the decay (0.4–0.5) and rebound rates (0.2–0.3) were similar throughout the pandemic and among all the nations and regions studied. Finally, a longitudinal analysis comparing multiple national and regional results provides insights on the underlying epidemiology of SARS-CoV-2 and intervention efficacy, as well as evidence for the existence of an endemic steady state of COVID-19.
Guest investigator David Thaler co-authors paper with novel idea for biological diaries
Published Open Access in Frontiers in Epidemiology: The Coronavirus Calendar (CoronaCal): a simplifiedSARS-CoV-2 test system for sampling and retrospective analysis by Manija A. Kazmi, David S. Thaler, Karina C. Åberg, Jordan M. Mattheisen, Thomas Huber and Thomas P. Sakmar
The paper concludes that sampling saliva on simple paper provides a useful method to study the natural history and epidemiology of COVID-19 (and probably many other microbes). The “CoronaCal” collection and testing method is easy to implement, inexpensive, non-invasive and scalable. The approach can inform the historical and epidemiological understanding of infections in individuals and populations.
The idea for the paper arose from efforts in the Leonardo Da Vinci DNA Project about stable preservation of genetic material on paper.
Our paper on eDNA as bioassay of Anthropocene published
The new journal based in China, The Innovation, has published the Thaler-Ausubel-Stoeckle paper on Human and domesticated animal environmental DNA as bioassays of the Anthropocene in their “Out of the Box” category, where we like to be. We also post the pdf.
We thank Song Sun and Ke Chen for editorial assistance.
Summary: Human and domesticated animal sequences, commonly detected in environmental DNA (eDNA) metabarcoding studies, are routinely excluded from analysis. Here we suggest that reporting human and domesticated animal eDNA results might open new lines of investigation. For example, the relative abundance of human and domesticated animal eDNA as compared to that of wild vertebrate species might provide an index of human impact on local biota. Such an index could be applied to sites ranging from urban harbors to remote villages, and possibly to analyze historical samples. Various potential sources of contamination complicate the picture, but it should be possible to develop procedures that minimize risk of DNA introduction during collection and processing. Our near-term recommendation is to encourage inclusion of human and domesticated animal data in eDNA publications as an incentive for discovery, to lift quality controls, and to collectively contribute to new vistas that eDNA science might open.
Human and domesticated animal environmental DNA as bioassays of the Anthropocene
Thaler memo on “Distinguishing contamination from authentic human eDNA”
PHE guest investigator David Thaler summarizes “Ways in which contamination might be distinguished from authentic human eDNA” in a useful draft memo. Meeting this challenge matters greatly for using human eDNA as an assay of the Anthropocene, a subject of a forthcoming paper by Thaler, Ausubel, and Stoeckle.
eDNA degradation; 2nd National Workshop
PHE’s guest investigator David Thaler offers some stimulating ideas in a memo about ways of understanding and learning from degradation of aquatic eDNA. The title: How long has each particular species’ eDNA been outside the organism from which it came? Some thoughts on the possibility to obtain more information from eDNA analysis of water samples
Meanwhile, Jesse Ausubel and Mark Stoeckle are involved in the program for the 2nd US National Workshop on eDNA, 12-15 September in Southern California. PHE hosted the 1st US national meeting in 2018.
Airborne DNA
PHE’s marine eDNA expert Mark Stoeckle comments on new papers on airborne eDNA in the video Scientists ID Dozens of Plants, Animals from Free-Floating DNA. In a trio of studies, researchers report capturing and analyzing airborne prepared for the magazine and website The Scientist. The report is spurred by widely reported terrific new papers measuring airborne DNA around zoos.
While presented as a first, this study of airborne DNA began in 2005 under the auspices of the Alfred P. Sloan Foundation. Paula Olsiewski and Jesse Ausubel recruited and managed a series of grants to explore the potential for airborne DNA studies. The largest grant went to the Venter Institute, which pioneered the techniques:
After Mapping the Human Genome, Analyzing the City’s Air Mar 7, 2005 — Dr J Craig Venter will study New York City’s air by installing filter system atop one of Midtown-Manhattan’s skyscrapers and studying its …
Among resulting publications: A metagenomic framework for the study of airborne microbial communities …, J Glass, MD Adams, R Friedman, JC Venter – PloS one, 2013 – journals.plos.org Understanding the microbial content of the air has important scientific, health, and economic implications. While studies have primarily characterized the taxonomic content of air samples by sequencing the 16S or 18S ribosomal RNA gene, direct analysis of the genomic …
Among other findings, while focusing on microbial aspects, the Venter team found more rat DNA circulating in the air of NY than human DNA.