Edinburgh Infectious Diseases
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Research focus: analysis of COVID-19 hospitalisations to infections associated with wildlife

A collection of publication highlights from the Edinburgh Infectious Diseases network over the past month.

Age-specific impacts of vegetation functional traits on gastrointestinal nematode parasite burdens in a large herbivore

Summary:  Researchers from the School of Biological Sciences were involved in a study of the spatial variation in gastrointestinal nematode parasite infection dynamics  in wild Soay sheep on St Kilda.  The findings support the importance of fine-scale environmental variation for wildlife disease ecology and provides new evidence that such effects may vary across demographic groups within a population.

Wiersma E, Pakeman RJ, Bal X, Pilkington JG, Pemberton JM, Nussey DH, Sweeny AR, J Anim Ecol. 2023 Sep;92(9):1869-1880. doi: 10.1111/1365-2656.13978

Analysis of Escherichia coli O157 strains in cattle and humans between Scotland and England & Wales: implications for human health

Summary:  Researchers from the Roslin Institute and colleagues studied the strain differences in national populations of E. coli O157 in cattle, and to what extent any strain variation was associated with higher human infection rates in Scotland. 

Despite comparable cattle O157 prevalence between nations, one particular lineage PT21/28 (sub-lineage Ic, Stx2a+) was significantly more prevalent in Scottish cattle and humans, than in England and Wales.  The authors propose the higher rate of O157 clinical cases in Scotland, is a consequence of the nationally higher level of Stx2a+O157 strains in Scottish cattle, and discuss the multiple additional factors that may also contribute to the different infection rates between these nations.

Chase-Topping M et al, Microb Genom. 2023 Sep;9(9). doi: 10.1099/mgen.0.001090

Evaluation of Nafamostat as Chemoprophylaxis for SARS-CoV-2 Infection in Hamsters

Summary: Researchers from the Centre for inflammation Research were involved in this study, which explored the potential of intranasal nafamostat treatment to prevent SARS-CoV-2 transmission in Syrian Golden hamsters.

Throat swabs from the control group showed detectable virus RNA after 4 days, whereas the nafamostat-treated hamsters remained RNA negative throughout the study. Furthermore, lower virus RNA levels were detected nasal isolates from  nafamostat-treated hamsters, and the concentration of infectious virus in the lungs of treated animals was also significantly lower.  These findings highlight intranasal nafamostat's promise for controlling SARS-CoV-2 infection.

Neary M at al, Viruses. 2023 Aug 15;15(8):1744. doi: 10.3390/v15081744

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Interventions to reduce camel and small ruminant young stock morbidity and mortality in Ethiopia

Summary:  Colleagues at the Royal (Dick) School of Veterinary Studies (SEBI group) assessed the impact of government-led interventions intended to improve the survival rates of farmed camels, sheep and goats in Ethiopia. 

Pastoralists and mixed crop-livestock farmers were given information to help reduce the incidence of diarrhoea and respiratory disease in their animals, and followed up over a one-year period.  The pilot study demonstrated highly significant reductions in mortality and risk of disease post-interventions, and should inform future research and policy-making to improve livestock productivity in Ethiopia.

Allan FK et al, Prev Vet Med. 2023 Aug 24;219:106005. doi: 10.1016/j.prevetmed.2023.106005

One for all-human kidney Caki-1 cells are highly susceptible to infection with corona- and other respiratory viruses

Summary:  A team the Roslin Institute has identified human kidney Caki-1 cell line as a potential target for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). This cell line could be shown to be infectable with a wide range of coronaviruses including common cold virus hCoV-229E, epidemic virus MERS-CoV, and SARS-CoV-2 as well as other important respiratory viruses influenza A virus and respiratory syncytial virus, making Caki-1 cells a unique tool for cross-virus comparison in one cell line.

Daniels A, Fletcher S, Kerr HEM , Kratzel A , Pinto RM, Kriplani N, Craig N, Hastie CJ, Davies P, Digard P, Thiel V, Tait-Burkard CJ Virol. 2023 Sep 5:e0055523. doi: 10.1128/jvi.00555-23

Prevalence of Shiga Toxin-Producing Escherichia coli O157 in Wild Scottish Deer with High Human Pathogenic Potential

Summary: Scientists from the Moredun Research Institute, Roslin Institute, and the E. coli Reference Laboratory conducted a study on Shiga toxin-producing E. coli (STEC) infections associated with wildlife.

Although the study found a low prevalence of STEC O157 (0.28%) in wild deer, researchers detected high levels in deer faeces that had significant human pathogenic potential.  Additionally, a wild deer isolate from this study was linked to a 2017 human outbreak of STEC infection, emphasising the importance of rigorous food hygiene practices when processing wild deer for human consumption.

Fitzgerald SF, Mitchell MC, Holmes A, Allison L, Chase-Topping M, Lupolova N, Wells B, Gally DL, McNeilly TN., Animals 2023 Sep 2;13(17):2795. doi: 10.3390/ani13172795

Sensitive poliovirus detection using nested PCR and nanopore sequencing: a prospective validation study

Summary: Researchers from the Institute of Ecology and Evolution were part of a study in the Democratic Republic of the Congo to improve poliovirus outbreak detection. They tested a faster method called Direct Molecular Detection and Nanopore Sequencing (DDNS) against the traditional gold standard.

DDNS detected polioviruses in 2.7% of samples, while the gold standard found them in 2.2%. DDNS confirmed cases within 7 days on average, compared to the gold standard's 30 days. It also detected outbreaks 23 days earlier, with a 99.98% sequence similarity. This study shows that DDNS can be implemented effectively for quicker outbreak detection.

Shaw AG et al, Nat Microbiol. 2023 Sep;8(9):1634-1640. doi: 10.1038/s41564-023-01453-4.

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γδ T cells control murine skin inflammation and subcutaneous adipose wasting during chronic Trypanosoma brucei infection

Summary: In a study of trypanosome infection, researchers used spatial and single-cell transcriptomics to investigate how the skin responds. They found an expansion of dermal IL-17A-producing Vγ6+ cells in subcutaneous adipose tissue during infection. In silico analysis indicated that subcutaneous preadipocytes trigger T cell activation.

In female mice lacking IL-17A-producing Vγ6+ cells, extensive inflammation occurred, and subcutaneous adipose tissue loss was limited, regardless of parasite burden. This suggests collaboration between subcutaneous adipocytes and Vγ6+ cells in controlling skin inflammation and adipose tissue loss.

The Roslin Institute contributed to this research, shedding light on skin immunity during chronic infection.

Quintana JF, Sinton MC, Chandrasegaran P, Lestari AN, Heslop R, Cheaib B, Ogunsola J, Ngoyi DM, Kuispond Swar NR, Cooper A, Mabbott NA, Coffelt  SB, MacLeod A, Nat Commun. 2023 Aug 29;14(1):5279. doi: 10.1038/s41467-023-40962-y.

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A multi-country analysis of COVID-19 hospitalizations by vaccination status

Summary: The study examined 83,163 hospitalized COVID-19 patients from 38 countries, comparing those who were vaccinated against SARS-CoV-2 with those who were not. The Usher Institute was part of the international consortium conducting the research. The findings showed that while unvaccinated patients more often reported typical symptoms, vaccinated patients had more comorbidities. There was also significant variation between countries in terms of in-hospital fatality risk and differences in outcomes between vaccinated and unvaccinated patients.

These findings will help guide healthcare resource allocation during future outbreaks and inform future international studies on how vaccination history impacts the clinical profile of hospitalized COVID-19 patients.

Gonçalves BP, et al; ISARIC Clinical Characterisation GroupMed. 2023 Sep 12;S2666-6340(23)00282-9. doi: 10.1016/j.medj.2023.08.005.

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