Reduction in transfer of micro-organisms between patients and staff using short-sleeved gowns and hand/arm hygiene in Intensive Care during the Covid pandemic: a simulation-based randomised trial

ABSTRACTBackgroundCurrent PPE practices in UK intensive care units involve “sessional” gown use. This protects staff, but puts patients at risk of nosocomial infection via PPE gowns. Anecdotal reports of such infections in ITUs during Covid are frequent. We therefore explored the use of short-sleeved gowns with hand and arm hygiene as an alternative to sessional gowns.MethodsITU Staff were invited for simulation suite training in Covid intubation and proning. They were trained in a specific hand and arm washing technique before performing simulated tasks using both standard and modified (short sleeved) PPE. Fluorescent powder was used to simulate micro-organisms, and detected using standardised photos under U/V light. Teams of staff were randomised to use standard or modified PPE first. Individuals were questioned about their feeling of personal safety, comfort and the patient’s safety at 4 intervals.Results68 staff and 17 proning volunteers were studied in 17 sessions. Modified PPE completely prevented staff contamination during Covid intubation, which occurred in 30/67 staff wearing standard PPE (p = 0.0029, McNemar). Conversely, proning volunteers were contaminated by staff in 15/17 sessions with standard PPE and in 1/17 with modified PPE (P = 0.0227 McNemar). Impressions of staff comfort were superior with modified PPE (p< 0.001, t-test); personal safety scored higher with standard PPE, but the difference decreased during the session (p<0.001 start, 0.068 end). Impressions of patient safety were initially similar (p=0.87) but finished strongly in favour of modified PPE (p<0.001).ConclusionsModified PPE using short sleeves and hand/arm cleansing appears superior to standard PPE with sessional gowns in preventing transfer of contamination between staff and patients. A clinical trial of this strategy is merited.

Reuse of Disposable Isolation Gowns in Rodent Facilities during a Pandemic

Reuse of disposable personal protective equipment is traditionally discouraged, yet in times of heightened medical applications such as the SARS CoV-2 pandemic, it can be difficult to obtain. In this article we examine the reuse of disposable gowns with respect to still providing personnel protection. XR7, a fluorescent powder, was used to track contamination of gowns after manipulation of rodent cages. Mouse cages were treated with XR7 prior to manipulations. Disposable gowns were labeled for single person use and hung in common procedure spaces within the vivarium between usages. A simulated rack change of 140 cages was completed using XR7-treated cages. One individual changed all cages with a break occurring after the first 70 cages, requiring the gown to be removed and reused once. To simulate research activities, 5 individuals accessed 3 XR7-treated cages daily for 5 d. Each mouse in the XR7-treated cages was manipulated at least once before returning cages to the housing room. Disposable gowns were reused 5 times per individual. Gowns, gloves, clothing, bare arms, and hands were scanned for fluorescence before and after removing PPE. Fluorescence was localized to gloves and gown sleeves in closest contact with animals and caging. No fluorescence was detected on underlying clothing, or bare arms and hands after removing PPE. Fluorescence was not detected in procedure spaces where gowns were hung. The lack of fluorescence on personnel or surfaces indicate that gowns can be reused 1 time for routine husbandry tasks and up to 5 times for research personnel. A method for decontamination of used gowns using Vaporized Hydrogen Peroxide (VHP) was also validated for use in areas where animals are considered high risk such as quarantine, or for fragile immunocompromised rodent colonies.

Methods of amphibian tracking

ntroduction: In this article, we present a literature review of modern, most common, and useful methods of amphibian tracking. Amphibians are the most sensitive group of animals and near 41 % of species are under the risk of extinction. Therefore, the research of spatial movements of amphibians is one of the most topical tasks of modern herpeto­logy. The information about the use of space is needed for practical protection of sensitive species of amphibians, for planning of protected areas, estimation of the potential danger for some groups of animals when designing infrastructure objects, such as roads. The movement studies gained popularity and have been undertaken since the second part of the 20th century. Such growth in the number of studies is related to the recent advances in radio-electronic technology that contributed to the creation of a range of instruments for automatic or semi-automatic tracking of individual animals. Unfortunately, most of such methods are still too expensive for scientists from developing countries. Thus, classical methods are still widely used. Results: We describe six methods of amphibians tracking: radioisotope tracking, automated radio telemetry, harmonic direction finding, radio frequency identification, fluorescent powder, spool tracking. Each of these methods allows collecting detailed information about spatial movements of individuals. Many of these tracking methods require using of a special tag, which is attached to an animal and used for its further detection. Different types of tags have identical functions but are based on different principles of use. Two of the described methods do not require using of tags and are cheap. These are fluorescent powder and spool tracking. In the article, we provide many links to grant programs and places where special equipment can be found. Conclusions: As a result of literature review, we created a table with concise information about all the described methods. Using this table one can choose the best method for an experiment. Keywords: amphibians, radiotelemetry, fluorescent powder, radioisotope tracking, spool tracking

Preregistered Report: The Effects of Marking Methodology on Mate Choice in Drosophila melanogaster

Mate choice is an important source of sexual selection and a key driver of evolutionary processes including adaptation and speciation. Drosophila species have become an important model system for studying mate choice in the lab. Mate choice experiments often require the marking of individual flies to make those flies identifiable to experimenters, and several marking methods have been developed. All of these methods have the potential to affect mating behavior, but the effects of different marking methods have not been systematically quantified and compared. In this experiment, we quantified and compared the effects of five marking methods commonly used for Drosophila melanogaster: wing clipping, applying paint to the thorax, applying marker pen to the wing, dusting flies with fluorescent powder, and dyeing flies by allowing them to ingest food coloring. Females mated with unmarked males more often than they mated with marked males, but we could not detect significant differences among marking methods. Latency to mate differed among marking methods, and also with the time of day and the time within the trial. We discuss how our results can help researchers plan studies that require the marking of Drosophila.

Differentiation of Multiple Fluorescent Powders, Powder Transfer, and Effect on Mating in Aedes aegypti (Diptera: Culicidae)

Five different fluorescent powders (orange, yellow, green, blue, and violet) were tested on Aedes aegypti adults to evaluate the differentiation of multiple fluorescent powder colors applied externally in the same female mosquito, their effect on coupling time, copulation time, insemination success, mate choice, and the extent of transference of powders between marked and unmarked individuals, either during copulation or same-sex interactions. Marking with multiple powders was evaluated after applying different powders in the same female at different times and combinations. The comparative effect of powders on mating was explored using different cross-combinations of marked/unmarked couples. Transference of powders between marked/unmarked individuals after copulation was checked in mated individuals, and between same-sex interactions by allowing them to interact under crowded and uncrowded conditions. Identification of the colors included in multiple markings in the same individual was possible when exploring almost all combinations (exception: green–yellow). No important effect of powder marking between cross-combinations was found on coupling time (overall 95% CI (Confidence Interval) 37.6–49.6 min), copulation time (overall 95% CI 17–20 s), insemination success, nor their mate choice. Transferred powder after copulation activity, concentrated in genitalia, legs, and the tip of wings, occurred in >80% of females and 100% of males. Powder transference in legs and genitalia, between same-sex individuals, occurred only in males (ranged between 23–35%) under both density conditions. The lack of important effects of these powders on the studied aspects of Ae. aegypti provides information about their usefulness and limitations, which should be recognized for future applications and to avoid bias.

Personality affects dynamics of an experimental pathogen in little brown bats

Host behaviour can affect host–pathogen dynamics and theory predicts that certain individuals disproportionately infect conspecifics during an epidemic. Consistent individual differences in behaviour, or personality, could influence this variation with the most exploratory or sociable individuals most likely to spread pathogens. We quantified exploration and sociability in little brown bats ( Myotis lucifugus ) and then experimentally manipulated exposure to a proxy pathogen (i.e. ultraviolet (UV) fluorescent powder) to test two related hypotheses: (i) more sociable and more exploratory individuals would be more likely to transmit infections to other individuals, and (ii) more sociable and more exploratory individuals uninfected with an invading pathogen would be more likely to acquire infections. We captured 10 groups of 16 bats at a time and held each group in an outdoor flight tent equipped with roosting-boxes. We used hole-board and Y-maze tests to quantify exploration and sociability of each bat and randomly selected one individual from each group for ‘infection’ with non-toxic, UV fluorescent powder. Each group of 10 bats was released into the flight tent for 24 h, which represented an experimental infection trial. After 24 h, we removed bats from the trial, photographed each individual under UV light and quantified infection intensity from digital photographs. As predicted, the exploratory behaviour of the experimentally infected individual was positively correlated with infection intensity in their group-mates, while more exploratory females had higher pathogen acquisition. Our results highlight the potential influence of host personality and sex on pathogen dynamics in wildlife populations.