Summary Background Most surgical masks are not certified for use as respiratory protective devices (RPDs). In the event of an influenza pandemic, logistical and practical implications such as storage ...and fit testing will restrict the use of RPDs to certain high-risk procedures that are likely to generate large amounts of infectious bioaerosols. Studies have shown that in such circumstances increased numbers of surgical masks are worn, but the protection afforded to the wearer by a surgical mask against infectious aerosols is not well understood. Aim To develop and apply a method for assessing the protection afforded by surgical masks against a bioaerosol challenge. Methods A dummy test head attached to a breathing simulator was used to test the performance of surgical masks against a viral challenge. Several designs of surgical masks commonly used in the UK healthcare sector were evaluated by measuring levels of inert particles and live aerosolised influenza virus in the air, from in front of and behind each mask. Findings Live influenza virus was measurable from the air behind all surgical masks tested. The data indicate that a surgical mask will reduce exposure to aerosolised infectious influenza virus; reductions ranged from 1.1- to 55-fold (average 6-fold), depending on the design of the mask. Conclusion We describe a workable method to evaluate the protective efficacy of surgical masks and RPDs against a relevant aerosolised biological challenge. The results demonstrated limitations of surgical masks in this context, although they are to some extent protective.
Healthcare workers caring for patients with high-consequence infectious diseases (HCIDs) require protection from pathogen exposure, for example by wearing personal protective equipment (PPE). ...Protection is acquired through the inherent safety of the PPE components, but also their safe and correct use, supported by adequate training and user familiarity. However, the evidence base for HCID PPE ensembles and any associated training is lacking, with subsequent variation between healthcare providers.
To develop an evidence-based assessment and training tool for evaluating PPE ensembles and doffing protocols, in the assessment of patients with suspected HCIDs.
VIOLET (Visualising Infection with Optimised Light for Education and Training) comprises a healthcare mannequin adapted to deliver simulated bodily fluids containing UV-fluorescent tracers. On demand and remotely operated, the mannequin projectile vomits (blue), coughs (red), has diarrhoea (yellow) and is covered in sweat (orange). Wearing PPE, healthcare staff participate in an HCID risk assessment and examination of the ‘patient’, thereby becoming exposed to these bodily fluids. Contamination of PPE is visualized and body-mapped under UV light before and after removal. Observational findings and participant feedback, around its use as a training exercise, is also recorded.
Significant contamination from different exposure events was seen, enabling evaluation of PPE and doffing procedures used. Observational data and participant feedback demonstrated its strengths and success as a training technique.
Simulation exercises using VIOLET provide evidence-based assessment of PPE ensembles, and are a valuable resource for training of healthcare staff in wearing and safe doffing of PPE.
Variations currently exist across the UK in the choice of personal protective equipment (PPE) used by healthcare workers when caring for patients with suspected high-consequence infectious diseases ...(HCIDs).
To test the protection afforded to healthcare workers by current PPE ensembles during assessment of a suspected HCID case, and to provide an evidence base to justify proposal of a unified PPE ensemble for healthcare workers across the UK.
One ‘basic level’ (enhanced precautions) PPE ensemble and five ‘suspected case’ PPE ensembles were evaluated in volunteer trials using ‘Violet’; an ultraviolet-fluorescence-based simulation exercise to visualize exposure/contamination events. Contamination was photographed and mapped.
There were 147 post-simulation and 31 post-doffing contamination events, from a maximum of 980, when evaluating the basic level of PPE. Therefore, this PPE ensemble did not afford adequate protection, primarily due to direct contamination of exposed areas of the skin. For the five suspected case ensembles, 1584 post-simulation contamination events were recorded, from a maximum of 5110. Twelve post-doffing contamination events were also observed (face, two events; neck, one event; forearm, one event; lower legs, eight events).
All suspected case PPE ensembles either had post-doffing contamination events or other significant disadvantages to their use. This identified the need to design a unified PPE ensemble and doffing procedure, incorporating the most protective PPE considered for each body area. This work has been presented to, and reviewed by, key stakeholders to decide on a proposed unified ensemble, subject to further evaluation.
The UK High-Consequence Infectious Diseases (HCID) Network of high-level isolation units provides care for patients with contact- or airborne-transmissible highly infectious and highly dangerous ...diseases. In most HCID units, the healthcare workers (HCWs) wear personal protective equipment (PPE) ensembles incorporating a powered air-purifying respirator (PAPR) for head and respiratory protection. Some PAPRs have components worn outside/over other PPE, necessitating decontamination of re-usable elements. Two alternative PAPRs, with all re-usable elements worn under PPE, were trialled in this study.
To undertake scenario-based testing of PAPRs and PPE to determine usability, comfort and ability to remove contaminated PPE without personal cross-contamination.
Trained healthcare volunteers (N=20) wearing PAPR/PPE ensembles were sprayed with ultraviolet fluorescent markers. They undertook exercises to mimic patient care, and subsequently, after doffing the contaminated PPE following an established protocol, any personal cross-contamination was visualized under ultraviolet light. Participants also completed a questionnaire to gauge how comfortable they found the PPE.
The ensembles were tested under extreme ‘worst case scenario’ conditions, augmented by physical and manual dexterity tests. Participating volunteers considered the exercise to be beneficial in terms of training and PPE evaluation. Data obtained, including feedback from questionnaires and doffing buddy observations, supported evidence-based decisions on the PAPR/PPE ensemble to be adopted by the HCID Network. One cross-contamination event was recorded in the ensemble chosen; this could be attributed to doffing error, and could therefore be eliminated with further practice.
The genetic rules that dictate legume-rhizobium compatibility have been investigated for decades, but the causes of incompatibility occurring at late stages of the nodulation process are not well ...understood. An evaluation of naturally diverse legume (genus Medicago) and rhizobium (genus Sinorhizobium) isolates has revealed numerous instances in which Sinorhizobium strains induce and occupy nodules that are only minimally beneficial to certain Medicago hosts. Using these ineffective strain-host pairs, we identified gain-of-compatibility (GOC) rhizobial variants. We show that GOC variants arise by loss of specific large accessory plasmids, which we call HR plasmids due to their effect on symbiotic host range. Transfer of HR plasmids to a symbiotically effective rhizobium strain can convert it to incompatibility, indicating that HR plasmids can act autonomously in diverse strain backgrounds. We provide evidence that HR plasmids may encode machinery for their horizontal transfer. On hosts in which HR plasmids impair N fixation, the plasmids also enhance competitiveness for nodule occupancy, showing that naturally occurring, transferrable accessory genes can convert beneficial rhizobia to a more exploitative lifestyle. This observation raises important questions about agricultural management, the ecological stability of mutualisms, and the genetic factors that distinguish beneficial symbionts from parasites.
The COVID-19 pandemic changed our world as we know it and continues to be a global problem three years since the pandemic began. Several vaccines were produced, but there was a considerable amount of ...societal turmoil surrounding them that has affected the way people view not only COVID-19 vaccines but all vaccines. We used a survey to compare how attitudes towards vaccination have changed in college students during the pandemic. An initial survey was administered in 2021, then a follow-up in 2022. Out of 316 respondents who answered the first survey, 192 completed the follow-up. The survey was designed to measure trends in changes to vaccine attitudes since the COVID-19 pandemic began. By comparing the first survey in 2021 and the follow-up, we found that roughly 55% of respondents' vaccine attitudes did not change, roughly 44% of respondents' attitudes towards vaccines became more positive, and only about 1% of the respondents' vaccine attitudes became more negative. Improved view of vaccines was associated with political views and increased trust in medicine and the healthcare system. Worsened opinions of vaccines were associated with a belief that the COVID-19 vaccine affected fertility.
Edenopteron, with a lower jaw some 48 cm long, and total length perhaps exceeding 3 m, is the largest Devonian lobe-fin known from semi-articulated remains. New material described from the type ...locality (Boyds Tower, south of Eden) includes three slightly smaller articulated skulls and jaws, and additional bones of the shoulder girdle. Another articulated skull roof, shoulder girdle and palate is described from a second locality (Hegarty Bay), about 10 km south of Boyds Tower. Both localities represent the upper part of the Worange Point Formation, of late Famennian age (uppermost Upper Devonian). The new morphological evidence supports a close relationship to the tristichopterids Mandageria and Cabonnichthys, from the slightly older (Frasnian, Upper Devonian) fossil fish assemblage at Canowindra, New South Wales. Features of the shoulder girdle (supracleithrum, anocleithrum) suggest that Edenopteron is more closely related to Mandageria than Cabonnichthys. Eight characters are used to define a tristichopterid subfamily Mandageriinae, to which Notorhizodon from the Middle Devonian of Antarctica is also referred. The Mandageriinae is endemic to East Gondwana (Australia-Antarctica). In combination with possibly the most primitive tristichopterid, Marsdenichthys from the Frasnian of Victoria, these distributions implicate East Gondwana as a likely place of origin for the entire group. This relates to the major but unresolved question of a possible Gondwana origin for all the land vertebrates (tetrapods).
An endemic Gondwanan sub-group (Mandageriinae) of the Devonian fishes closest to land animals (tetrapodomorph tristichopterids) is confirmed.
Retention of primitive features (e.g. accessory vomers) points to an earlier origin of the Mandageriinae in East Gondwana, consistent with the Victorian occurrence of another primitive tristichopterid (Marsdenichthys).
Edenopteron is confirmed from a second south coast fossil site, and new characters indicate its closest relative is Mandageria from Canowindra, NSW.
Congruent evidence of older Gondwanan occurrences in other groups (basal tetrapodomorphs, rhizodontids, canowindrids), and previously dismissed trace fossil evidence (Grampians trackways), implicate South China and East Gondwana as the likely place of origin for all land vertebrates.
Aims
We constantly interact with our surrounding microbiome, including the micro‐organisms present in highly populated public places. However, data on everyday exposure to background levels of ...micro‐organisms are limited. To address this, bacteria and fungi were collected and enumerated in settled dust from railway stations.
Methods and Results
Samples were collected weekly for 52 weeks, from up to three pre‐determined surfaces in each of 17 railway stations in England and Scotland. Trained staff at each station took surface wipes, sending them to the laboratory for culture‐based analysis for total bacteria and fungi. Maximum yields of bacteria at the stations were 107–108 colony forming units (CFU) per cm2, and 104–105 CFU per cm2 for fungi.
Conclusions
There was evidence of seasonal trends, with bacterial numbers rising from spring through to winter, while fungal numbers peaked in autumn. Microbial numbers were similar in samples taken at the same time at a given station. Influences on contamination levels were likely to be a combination of passenger numbers and station layout, with dust generated from construction work also contributing.
Significance and Impact of the Study
A baseline of typical human exposure to micro‐organisms in public transport hubs was established through the generation of a comprehensive database.
The symbiotic nitrogen-fixing bacterium Sinorhizobium meliloti harbors a gene, SMc02396, which encodes a predicted outer membrane porin that is conserved in many symbiotic and pathogenic bacteria in ...the order Rhizobiales. Here, this gene (renamed ropA1) is shown to be required for infection by two commonly utilized transducing bacteriophages (ΦM12 and N3). Mapping of S. meliloti mutations conferring resistance to ΦM12, N3, or both phages simultaneously revealed diverse mutations mapping within the ropA1 open reading frame. Subsequent tests determined that RopA1, lipopolysaccharide, or both are required for infection by all of a larger collection of Sinorhizobium-specific phages. Failed attempts to disrupt or delete ropA1 suggest that this gene is essential for viability. Phylogenetic analysis reveals that ropA1 homologs in many Rhizobiales species are often found as two genetically linked copies and that the intraspecies duplicates are always more closely related to each other than to homologs in other species, suggesting multiple independent duplication events.
Background and purpose: The peroxisome proliferator‐activated receptor‐γ (PPARγ) agonist pioglitazone has previously been shown to attenuate dopaminergic cell loss in the ...1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) mouse model of Parkinson's disease, an effect attributed to its anti‐inflammatory properties. In the present investigation, we provide evidence that pioglitazone is effective in the MPTP mouse model, not via an anti‐inflammatory action, but through inhibition of MAO‐B, the enzyme required to biotransform MPTP to its active neurotoxic metabolite 1‐methyl‐4‐phenylpyridinium (MPP+).
Experimental approach: Mice were treated with pioglitazone (20 mg kg−1 b.i.d. (twice a day), p.o., for 7 days), prior and post or post‐MPTP (30 mg kg−1 s.c.) treatment. Mice were then assessed for motor impairments on a beam‐walking apparatus and for reductions in TH immunoreactivity in the substantia nigra and depletions in striatal dopamine. The effects of pioglitazone on striatal MPP+ levels and MAO‐B activity were also assessed.
Key results: Mice treated with MPTP showed deficits in motor performance, marked depletions in striatal dopamine levels and a concomitant reduction in TH immunoreactivity in the substantia nigra. Pretreatment with pioglitazone completely prevented these effects of MPTP. However, pretreatment with pioglitazone also significantly inhibited the MPTP‐induced production of striatal MPP+ and the activity of MAO‐B in the striatum.
Conclusions and implications: The neuroprotection observed with pioglitazone pretreatment in the MPTP mouse model was due to the blockade of the conversion of MPTP to its active toxic metabolite MPP+, via inhibition of MAO‐B.
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