Research Focus: From the cleaning practices of livestock transport vehicles to behaviour in fruit flies

December 2024: A collection of publication highlights from Edinburgh Infectious Diseases over the past month.

Scottish livestock transport
Scottish livestock transport vehicle

Cleaning practices of transport vehicles by commercial and non-commercial livestock markets users in Scotland

Researchers from the Royal (Dick) School of Veterinary Medicine have be looking into the cleaning practices of transport vehicles by livestock markets users in Scotland.

 

Livestock markets are critical intermediaries in the movement of cattle and sheep between herds and to abattoirs however, little is known about how market users implement Cleaning & Disinfection (C&D) on their vehicles and how these may differ between sectors of the industry.

 

The results of an online survey conducted by researchers showed a lower-than-expected use of brush or disinfectant and a shorter-than-expected time spent on C&D.

 

Citation: Allen R, Boden LA, Hutchinson I, Stirling J, Porphyre T. Res Vet Sci. 2024 Nov;180:105413. doi: 10.1016/j.rvsc.2024.105413. Epub 2024 Sep 11. PMID: 39270505.

Systematic review and meta-analysis of COVID-19 mRNA vaccine effectiveness against hospitalizations in adults

During the Coronavirus disease 2019 (COVID-19) pandemic, Pfizer/BioNTech BNT162b2 and Moderna mRNA-1273 vaccines were central to the global pandemic control measures.

 

Researchers from The Roslin Institute conducted a systematic review and meta-analysis to evaluate their real-world vaccine effectiveness (VE). Their study focussed on those that reported the efficacy of these vaccines against COVID-19 hospitalization.

 

High VE against hospitalization was reported for both the BNT162b2 and mRNA-1273 COVID-19 vaccines when used either as a primary vaccination series (2-dose) or following an additional booster dose (3-dose).  However, subgroup analysis revealed an association between the presence of the Omicron variant and a drop in VE, indicating that future emerging SARS-CoV-2 virus variants could similarly affect VE.

 

Their review underscores the importance of ongoing research to ensure vaccine strategies remain effective against evolving variants. Our study also identified the need for expanding data collection to include underrepresented populations.

 

Citation: Bill Wong, Neil A Mabbott, Immunotherapy Advances, 2024, ltae011, https://doi.org/10.1093/immadv/ltae011

Investigation of parasite genetic variation and systemic immune responses in patients presenting with different clinical presentations of cutaneous leishmaniasis caused by Leishmania aethiopica

Researchers from the Centre for Inflammation Research have been studying Cutaneous Leishmaniasis which is a neglected tropical skin disease. In Ethiopia CL presents in several clinical forms and can be a devastating disease. 

 

The cycle of infection is complex, involving human infection, sandfly transmission, leishmania parasites and mammalian reservoirs. The team in Ethiopia where the study has been based, has been trying to determine the reasons for the different presentations of CL, which might help us be able to control the disease better. 

 

In this paper researchers describe how it doesn't appear to be due to genetic differences in the parasites, nor is it obvious differences in the immune response of infected patients. The hunt thus continues.

 

Citation: Yizengaw, E., Takele, Y., Franssen, S. et al. Infect Dis Poverty 13, 76 (2024). https://doi.org/10.1186/s40249-024-01244-x.

New sleeper frameworks to help better prepare for future pandemics

Researchers from The Usher Institute, have developed a set of ‘sleeper frameworks’ – strategic plans designed for rapid deployment to significantly enhance disease surveillance and response capabilities – for use during future epidemics and pandemics.

 

These frameworks build on lessons learnt from the UK’s response to recent swine flu (H1N1) and COVID-19 pandemics. They aim to address key needs, including improving surveillance of pathogens that cause outbreaks, using evolving data to rapidly identify those at risk of death and other severe outcomes, and implementing real-time monitoring of vaccine uptake, safety and effectiveness. 

 

Citation: Shi T, Gu X, Meza-Torres B, et al. 2024. Available at here. 

SID-2 is a conserved extracellular vesicle protein that is not associated with environmental RNAi in parasitic nematodes

Researchers from the Institute of Immunology and Infectioon Research, the Wellcome Centre for Cell Biology and the Institute of Quantitative Biology, Biochemistry and Biotechnology have been looking at Caenorhabditis elegans which is a free-living transparent nematode.

 

In this nematode, the protein SID-2 imports Ribonucleic acid (RNA) into intestinal cells to trigger RNA interference. RNA interference (RNAi) describes a cellular mechanism that uses the gene's own DNA sequence to turn it off. This allows organisms to sense and respond to environmental cues such as the presence of pathogens.

 

This process has not been observed in the most closely related parasites that are also within clade V (a class of parasites). 

 

In this paper, researchers identified SID-2 orthologues in these parasites. Their work identifies SID-2 as a highly abundant EV protein whose ancestral function may be unrelated to environmental RNAi, and rather highlights an association with extracellular vesicles in nematodes.

 

Citation: Blow F, Jeffrey K, Chow FW, Nikonorova IA, Barr MM, Cook AG, Prevo B, Cheerambathur DK, Buck AH. Open Biol. 2024 Nov;14(11):240190. doi: 10.1098/rsob.240190. Epub 2024 Nov 6. 

Modelling plausible scenarios for the Omicron SARS-CoV-2 variant from early-stage surveillance

Researchers from the Roslin Institute have been looking at scenarios they ran for Scottish Government early in the outbreak of the new Omicron VOC. 

 

The method they used employed a relatively simple fitting technique applied to an existing complex model, which gave a rapid estimate and also stood up to retrospective scrutiny. 

 

Researchers found that proposed NPIs at the time would likely have little effect (too late) and neither would a change in vaccination strategy. The main determinant of the outbreak dynamics was the prior immunity and vaccination distribution landscape.

 

Citation: Banks, C.J., Colman, E., Wood, A., Doherty, T., Kao, R.R., (2024) Epidemics.

Genetic Variation in Trophic Avoidance Behaviour Shows Fruit Flies are Generally Attracted to Bacterial Substrates

Pathogen avoidance behaviours are often assumed to be an adaptive host defence, but there is limited  data on how pathogen avoidance varies between individuals.

 

Researchers from the Institute of Ecology and Evolution investigated pathogen avoidance in fruit flies, by tracking the feeding choice that flies made between substrates that were either clean or contained a bacterial pathogen. Instead of avoidance, most lines demonstrated a preference for substrates containing several bacterial pathogens, showing avoidance only for extremely high bacterial concentrations. Bacterial preference was not associated with susceptibility to infection but instead was associated with genes involved in protein sensing. 

 

These results suggest that bacterial attraction may instead reflect a dietary preference for protein. More work quantifying intrapopulation variation in avoidance behaviours is needed to fully assess its importance in host–pathogen evolutionary ecology.

 

Citation: Monteith, K. M.; Thornhill, P.; and Vale, P. F. Ecology and Evolution, 14(11): e70541. 2024.

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