Publications by authors named "K G Thompson"

3,026 Publications

  • Page 1 of 1

Persistence of SARS-CoV-2 virus and viral RNA in relation to surface type and contamination concentration.

Appl Environ Microbiol 2021 May 7. Epub 2021 May 7.

Public Health England, National Infection Service, Porton Down, Wiltshire, UK

The transmission of SARS-CoV-2 is likely to occur through a number of routes, including contact with contaminated surfaces. Many studies have used RT-PCR analysis to detect SARS-CoV-2 RNA on surfaces but seldom has viable virus been detected. This paper investigates the viability over time of SARS-CoV-2 dried onto a range of materials and compares viability of the virus to RNA copies recovered, and whether virus viability is concentration dependant.Viable virus persisted for the longest time on surgical mask material and stainless steel with a 99.9% reduction in viability by 122 and 114 hours respectively. Viability of SARS-CoV-2 reduced the fastest on a polyester shirt, with a 99.9% reduction within 2.5 hours. Viability on the bank note was reduced second fastest, with 99.9% reduction in 75 hours. RNA on all the surfaces exhibited a one log reduction in genome copy recovery over 21 days.The findings show that SARS-CoV-2 is most stable on non-porous hydrophobic surfaces. RNA is highly stable when dried on surfaces with only one log reduction in recovery over three weeks. In comparison, SARS-CoV-2 viability reduced more rapidly, but this loss in viability was found to be independent of starting concentration. Expected levels of SARS-CoV-2 viable environmental surface contamination would lead to undetectable levels within two days. Therefore, when RNA is detected on surfaces it does not directly indicate presence of viable virus even at high CT values.This study shows the impact of material type on the viability of SARS-CoV-2 on surfaces. It demonstrates that the decay rate of viable SARS-CoV-2 is independent of starting concentration. However, RNA shows high stability on surfaces over extended periods. This has implications for interpretation of surface sampling results using RT-PCR to determine the possibility of viable virus from a surface, where RT-PCR is not an appropriate technique to determine viable virus. Unless sampled immediately after contamination it is difficult to align RNA copy numbers to quantity of viable virus on a surface.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/AEM.00526-21DOI Listing
May 2021

The impact of disruptions caused by the COVID-19 pandemic on global polio eradication.

Vaccine 2021 Apr 27. Epub 2021 Apr 27.

Kid Risk, Inc., Orlando, FL, USA. Electronic address:

In early 2020, the COVID-19 pandemic led to substantial disruptions in global activities. The disruptions also included intentional and unintentional reductions in health services, including immunization campaigns against the transmission of wild poliovirus (WPV) and persistent serotype 2 circulating vaccine-derived poliovirus (cVDPV2). Building on a recently updated global poliovirus transmission and Sabin-strain oral poliovirus vaccine (OPV) evolution model, we explored the implications of immunization disruption and restrictions of human interactions (i.e., population mixing) on the expected incidence of polio and on the resulting challenges faced by the Global Polio Eradication Initiative (GPEI). We demonstrate that with some resumption of activities in the fall of 2020 to respond to cVDPV2 outbreaks and full resumption on January 1, 2021 of all polio immunization activities to pre-COVID-19 levels, the GPEI could largely mitigate the impact of COVID-19 to the delays incurred. The relative importance of reduced mixing (leading to potentially decreased incidence) and reduced immunization (leading to potentially increased expected incidence) depends on the timing of the effects. Following resumption of immunization activities, the GPEI will likely face similar barriers to eradication of WPV and elimination of cVDPV2 as before COVID-19. The disruptions from the COVID-19 pandemic may further delay polio eradication due to indirect effects on vaccine and financial resources.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.vaccine.2021.04.026DOI Listing
April 2021

Ocean-wide genomic variation in Gray's beaked whales, .

R Soc Open Sci 2021 Mar 24;8(3):201788. Epub 2021 Mar 24.

GLOBE Institute, University of Copenhagen, Denmark.

The deep oceans of the Southern Hemisphere are home to several elusive and poorly studied marine megafauna. In the absence of robust observational data for these species, genetic data can aid inferences on population connectivity, demography and ecology. A previous investigation of genetic diversity and population structure in Gray's beaked whale () from Western Australia and New Zealand found high levels of mtDNA diversity, no geographic structure and stable demographic history. To further investigate phylogeographic and demographic patterns across their range, we generated complete mitochondrial and partial nuclear genomes of 16 of the individuals previously analysed and included additional samples from South Africa ( = 2) and South Australia ( = 4), greatly expanding the spatial range of genomic data for the species. Gray's beaked whales are highly elusive and rarely observed, and our data represents a unique and geographically broad dataset. We find relatively high levels of diversity in the mitochondrial genome, despite an absence of population structure at the mitochondrial and nuclear level. Demographic analyses suggest these whales existed at stable levels over at least the past 1.1 million years, with an approximately twofold increase in female effective population size approximately 250 thousand years ago, coinciding with a period of increased Southern Ocean productivity, sea surface temperature and a potential expansion of suitable habitat. Our results suggest that Gray's beaked whales are likely to be resilient to near-future ecosystem changes, facilitating their conservation. Our study demonstrates the utility of low-effort shotgun sequencing in providing ecological information on highly elusive species.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1098/rsos.201788DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8074979PMC
March 2021

Differential Contributions of DNA-Binding Proteins to Polycomb Response Element Activity at the Drosophila giant Gene.

Genetics 2020 Mar;214(3):623-634

Department of Biological Sciences, Southern Methodist University, Dallas, Texas 75275-0376.

Polycomb-group (PcG) proteins utilize epigenetic mechanisms to maintain the transcriptional silence of target genes. Recruitment of Drosophila PcG proteins to target genes requires the presence of a Polycomb Response Element (PRE). Some PcG target genes, including... Polycomb-group (PcG) proteins are evolutionarily conserved epigenetic regulators whose primary function is to maintain the transcriptional repression of target genes. Recruitment of Drosophila melanogaster PcG proteins to target genes requires the presence of one or more Polycomb Response Elements (PREs). The functions or necessity for more than one PRE at a gene are not clear and individual PREs at some loci may have distinct regulatory roles. Various combinations of sequence-specific DNA-binding proteins are present at a given PRE, but only Pleiohomeotic (Pho) is present at all strong PREs. The giant (gt) locus has two PREs, a proximal PRE1 and a distal PRE2. During early embryonic development, Pho binds to PRE1 ∼30-min prior to stable binding to PRE2. This observation indicated a possible dependence of PRE2 on PRE1 for PcG recruitment; however, we find here that PRE2 recruits PcG proteins and maintains transcriptional repression independently of Pho binding to PRE1. Pho-like (Phol) is partially redundant with Pho during larval development and binds to the same DNA sequences in vitro. Although binding of Pho to PRE1 is dependent on the presence of consensus Pho-Phol-binding sites, Phol binding is less so and appears to play a minimal role in recruiting other PcG proteins to gt. Another PRE-binding protein, Sp1/Kruppel-like factor, is dependent on the presence of Pho for PRE1 binding. Further, we show that, in addition to silencing gene expression, PcG proteins dampen transcription of an active gene.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1534/genetics.119.302981DOI Listing
March 2020

Community health workers and care of older adults: How to learn what we need to know.

J Am Geriatr Soc 2021 May 5. Epub 2021 May 5.

Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jgs.17186DOI Listing
May 2021