Comparative Inactivation of Three Different Subtypes of Avian Influenza Virus by Ozonized Water.

Avian influenza virus (AIV) causes frequent outbreaks in poultry with high morbidity and mortality. The virus can survive on different fomites, resulting in indirect transmission to susceptible hosts. We investigated the inactivation by ozonated water (O3W) of three different subtypes of AIV (H4N8, H4N6, and H9N9) on seven different fomites. All subtypes were sensitive on all fomites, but there was a slight variation in the sensitivity of different subtypes. For example, AIV H9N9 showed more than 99% reduction on denim fabric, polypropylene, and Styrofoam after 3 min of exposure. More than 97% of H4N8 was eliminated from cardboard, denim fabric, and stainless steel after 3 min of exposure. Subtype H4N6 was the least sensitive; highest inactivation (98%) was seen on cardboard and polypropylene after 3 min of exposure. In conclusion, O3W can inactivate a large percentage of AIV applied to fomites within 3 min in all tested subtypes. Interestingly, an increase in contact time to 10 min did not result in an increase in the virus inactivation rate, probably because of the low half-life of ozone. Further studies are needed to determine how the residual virus can be inactivated so that it does not pose a problem to naïve birds.

Inactivación comparativa de tres subtipos diferentes del virus de la influenza aviar mediante agua ozonizada. El virus de la influenza aviar causa frecuentes brotes en aves la avicultura con alta morbilidad y mortalidad. El virus puede sobrevivir en diferentes fómites, lo que resulta en transmisión indirecta a huéspedes susceptibles. Se investigó la inactivación mediante agua ozonizada de tres subtipos diferentes del virus de la influenza aviar (H4N8, H4N6 y H9N9) en siete fómites diferentes. Todos los subtipos fueron sensibles al agua ozonizada (O3W) en todos los fómites, pero hubo una ligera variación en la sensibilidad de los diferentes subtipos. Por ejemplo, el virus subtipo H9N9 mostró una reducción de más del 99 % en tela de mezclilla, polipropileno y espuma de poliestireno después de tres minutos de exposición. Más del 97% del subtipo H4N8 se eliminó del cartón, la mezclilla y el acero inoxidable después de tres minutos de exposición. El subtipo H4N6 fue el menos sensible; La inactivación más alta (98%) se observó en cartón y polipropileno después de tres minutos de exposición. En conclusión, el agua ozonizada puede inactivar un gran porcentaje del virus de influenza aviar aplicado a fómites en tres minutos en todos los subtipos estudiados. Curiosamente, un aumento en el tiempo de contacto a 10 minutos no resultó en un aumento en la tasa de inactivación del virus, probablemente debido a la baja vida media del ozono. Se necesitan más estudios para determinar cómo se puede inactivar el virus residual para que no represente un problema para las aves susceptibles.

Molecular characterisation of virulence genes in bacterial pathogens from daycare centres in Ile-Ife, Nigeria: implications for infection control.

BACKGROUND: Daycare centres play a critical role in early childhood development but are high-risk environments for infectious disease transmission due to close physical contact, shared toys, inadequate hygiene, and poor ventilation. These risks are especially concerning in low- and middle-income countries (LMICs) like Nigeria, where resources for infection control may be limited. This study aimed to identify and characterise virulence genes in bacterial isolates from daycare centres in Ile-Ife, Nigeria, to assess infection risks. METHODS: Between November 2017 and July 2019, 233 samples were collected from 76 children, 33 daycare workers, and 124 fomites in 17 daycare centres. The bacterial isolates were analysed using conventional PCR and RAPD analysis to detect the presence of virulence genes. The frequency of crucial virulence genes and the prevalence of each bacterial species were recorded. RESULTS: Key virulence genes were detected, including fimH in Klebsiella species (22.73% of Gram-negative isolates), algD in Pseudomonas aeruginosa (50%), and icaA and cna in Staphylococcus aureus (16.67%). Staphylococcus aureus was the most prevalent species (35%), followed by Klebsiella (28%) and Pseudomonas aeruginosa (20%). CONCLUSION: This study highlights the presence of virulent bacterial pathogens in daycare environments, posing a severe infection risk to children. To mitigate these risks, it is essential to implement enhanced infection control measures, such as regular microbial screening, improved hand hygiene practices, and disinfection protocols for fomites. Training programs for daycare workers on hygiene practices and routine monitoring could also significantly reduce infection transmission. These interventions are vital for safeguarding the health of daycare children in Nigeria and similar settings globally.

SARS-CoV-2 infection and transmission via the skin to oro-nasal route with the production of bioaerosols in the ferret model.

Direct and indirect transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been attributed to virus survival in droplets, bioaerosols and on fomites including skin and surfaces. Survival of SARS-CoV-2 variants of concern (Alpha, Beta, Gamma, and Delta) on the skin and virus transference following rounds of skin-to-skin contact were assessed on porcine skin as a surrogate for human skin. SARS-CoV-2 variants were detectable on skin by RT-qPCR after 72 h at biologically relevant temperatures (35.2 °C) with viral RNA (vRNA) detected after ten successive skin-to-skin contacts. Skin-to-skin virus transmission to establish infection in ferrets as a model for mild/asymptomatic SARS-CoV-2 infection in mustelids and humans was also investigated and compared to intranasal ferret inoculation. Naïve ferrets exposed to Delta variant SARS-CoV-2 in a 'wet' or 'dry' form on porcine skin resulted in robust infection with shedding detectable for up to 14 days post-exposure, at comparable viral loads to ferrets inoculated intranasally. Transmission of SARS-CoV-2 to naïve ferrets in direct contact with infected ferrets was achieved, with environmental contamination detected from ferret fur swabs and air samples. Genetic substitutions were identified in bioaerosol samples acquired following single contact passage in ferrets, including Spike, ORF1ab, and ORF3a protein sequences, suggesting a utility for monitoring host adaptation and virus evolution via air sampling. The longevity of SARS-CoV-2 variants survival directly on the skin and skin-to-skin transference, enabling subsequent infection via the skin to oro-nasal contact route, could represent a pathway for SARS-CoV-2 infection with implications to public and veterinary health.

Fomite disinfection using spray systems: A computational multi-physics framework.

Disinfecting inanimate objects or materials carrying infectious agents, i.e., fomites, using spray systems reduces healthcare-associated infections in medical settings and community-acquired infections in non-medical environments. However, an accurate prediction of such systems is challenging as these systems embrace multi-physics phenomena depending on several parameters. Therefore, this paper presents a computational modeling-based multi-physics framework to evaluate the performance and effectiveness of spray systems employed in disinfecting fomites with non-porous hydrophilic surfaces. The framework includes four key phases: (i) atomizing the liquid disinfectant jet into the disinfectant droplets; (ii) interactions between disinfectant droplets and the surrounding air; (iii) impingements created by the disinfectant droplets on the fomite surface; (iv) interactions between the disinfectant depositions and pathogens causing fomite disinfection. The accuracy of the framework is evaluated using two sets of experimental data on the reduction of viable Bacillus atrophaeus spores over an 1800-second period. The results show that the framework can predict fomite disinfection via spray systems, with the deviations from the measured data being 2.73% and 2.38%. By presenting a detailed perception of the dynamics involved in fomite disinfection, this framework has the potential to improve public health practices and lead to the development of more effective and targeted disinfection strategies in diverse settings.

A coupled hand and surface hygiene criterion on heterogeneous surface touch networks.

Contaminated hands of people and contaminated surfaces of inanimate objects (fomites) can spread microbes that cause enteric and respiratory infections. Thus, hand hygiene and surface hygiene are probably the most widely adopted public health interventions for controlling such infections. However, conclusions of studies on the effectiveness of these interventions are often inconsistent, likely because such studies have examined these interventions separately and thus not detected their interactions, leading to differing conclusions about their individual impact. In this study, it is proposed that hand and environmental surface hygiene (including disinfection) should be coupled to control contamination spread between surfaces, especially within heterogeneous surface touch networks. In these networks, surfaces and individuals have varying contact frequencies and patterns, reflecting the diverse and non-uniform interactions that typically occur in real-world environments. Accordingly, we propose a new theoretical framework to delineate the relationships between hand hygiene and surface hygiene. In addition, the performance of a model based on this framework that used real-world behavioural data from a graduate student office is reported. Moreover, a coupled hygiene criterion for heterogeneous networks is derived. This criterion stipulates that the product of the pathogen-removal rates for hands and surfaces must exceed a cleaning threshold to ensure the exponential decay of contamination. Failure to meet this threshold results in a non-zero steady prevalence of contamination. Furthermore, the cleaning threshold increases as the numbers of surfaces and hands increase, highlighting the significant impact of network structures on hygiene practices. Thus, extensive cleaning may be necessary in crowded indoor environments with many surfaces and occupants, such as cruise ships, to prevent super-large outbreaks of, for example, noroviral infections. Overall, the findings of this study reveal how improved and integrated hygiene control can prevent fomite transmission.

Effect of multifunctional cationic polymer coatings on mitigation of broad microbial pathogens.

Infection control measures to prevent viral and bacterial infection spread are critical to maintaining a healthy environment. Pathogens such as viruses and pyogenic bacteria can cause infectious complications. Viruses such as SARS-CoV-2 are known to spread through the aerosol route and on fomite surfaces, lasting for a prolonged time in the environment. Developing technologies to mitigate the spread of pathogens through airborne routes and on surfaces is critical, especially for patients at high risk for infectious complications. Multifunctional coatings with a broad capacity to bind pathogens that result in inactivation can disrupt infectious spread through aerosol and inanimate surface spread. This study uses C-POLAR, a proprietary cationic, polyamine, organic polymer with a charged, dielectric property coated onto air filtration material and textiles. Using both SARS-CoV-2 live viral particles and bovine coronavirus models, C-POLAR-treated material shows a dramatic 2-log reduction in circulating viral inoculum. This reduction is consistent in a static room model, indicating simple airflow through a static C-POLAR hanging can capture significant airborne particles. Finally, Gram-positive and Gram-negative bacteria are applied to C-POLAR textiles using a viability indicator to demonstrate eradication on fomite surfaces. These data suggest that a cationic polymer surface can capture and eradicate human pathogens, potentially interrupting the infectious spread for a more resilient environment. IMPORTANCE: Infection control is critical for maintaining a healthy home, work, and hospital environment. We test a cationic polymer capable of capturing and eradicating viral and bacterial pathogens by applying the polymer to the air filtration material and textiles. The data suggest that the simple addition of cationic material can result in the improvement of an infectious resilient environment against viral and bacterial pathogens.

Weather-related changes in the dehydration of respiratory droplets on surfaces bolster bacterial endurance.

HYPOTHESIS: The study shows for the first time a fivefold difference in the survivability of the bacterium Pseudomonas Aeruginosa (PA) in a realistic respiratory fluid droplet on fomites undergoing drying at different environmental conditions. For instance, in 2023, the annual average outdoor relative humidity (RH) and temperature in London (UK) is 71 % and 11 °C, whereas in New Delhi (India), it is 45 % and 26 °C, showing that disease spread from fomites could have a demographic dependence. Respiratory fluid droplet ejections containing pathogens on inanimate surfaces are crucial in disease spread, especially in nosocomial settings. However, the interplay between evaporation dynamics, internal fluid flow and precipitation and their collective influence on the distribution and survivability of pathogens at different environmental conditions are less known. EXPERIMENTS: Shadowgraphy imaging is employed to study evaporation, and optical microscopy imaging is used for precipitation dynamics. Micro-particle image velocimetry (MicroPIV) measurements reveal the internal flow dynamics. Confocal imaging of fluorescently labelled PA elucidates the bacterial distribution within the deposits. FINDINGS: The study finds that the evaporation rate is drastically impeded during drying at elevated solutal concentrations, particularly at high RH and low temperature conditions. MicroPIV shows reduced internal flow under high RH and low temperature (low evaporation rate) conditions. Evaporation rate influences crystal growth, with delayed efflorescence and extending crystallization times. PA forms denser peripheral arrangements under high evaporation rates and shows a fivefold increase in survivability under low evaporation rates. These findings highlight the critical impact of environmental conditions on pathogen persistence and disease spread from inanimate surfaces.

Routes of SARS-Cov2 transmission in the intensive care unit: A multicentric prospective study.

BACKGROUND: The risk of SARS-CoV-2 transmission to health care workers in intensive care units (ICU) and the contribution of airborne and fomites to SARS-CoV-2 transmission remain unclear. To assess the rate of air and surface contamination and identify risk factors associated with this contamination in patients admitted to the ICU for acute respiratory failure due to SARS-CoV-2 pneumonia. METHODS: Prospective multicentric non-interventional study conducted from June 2020 to November 2020 in 3 French ICUs. For each enrolled patient, 3 predefined surfaces were swabbed, 2 air samples at 1 m and 3 m from the patient's mouth and face masks of 3 health care workers (HCW) were collected within the first 48 h of SARS-CoV-2 positive PCR in a respiratory sample. Droplet digital PCR and quantitative PCR were performed on different samples, respectively. RESULTS: Among 150 included patients, 5 (3.6%, 95%CI: 1.2% to 8.2%) had positive ddPCR on air samples at 1 m or 3 m. Seventy-one patients (53.3%, CI95%: 44.5% to 62.0%) had at least one surface positive. Face masks worn by HCW were positive in 6 patients (4.4%, CI: 1.6% to 9.4%). The threshold of RT-qPCR of the respiratory sample performed at inclusion (odds ratio, OR= 0.88, 95%CI: 0.83 to 0.93, p < 0.0001) and the presence of diarrhea (OR= 3.28, 95%CI: 1.09 to 9.88, p = 0.037) were significantly associated with the number of contaminated surfaces. CONCLUSION: In this study, including patients admitted to the ICU for acute respiratory failure " contact route " of transmission, i.e. through fomites, seems dominant. While presence of SARS-CoV-2 in the air is rare in this specific population, the presence of diarrhea is associated to surface contamination around Covid patients.

Antimicrobial resistance, enterotoxin and biofilm production genes in Staphylococcus spp. isolated from facilities and fomites in veterinary hospital in the Caatinga biome.

The Caatinga biome occurs only in Brazil and offers epidemiological conditions that should be assessed differently from other regions of Brazil and the world. Thus, the aim of this survey was to identify antimicrobial resistance, enterotoxin and biofilm production genes in Staphylococcus spp. isolated from facilities and fomites in a veterinary hospital in Caatinga biome. Samples were collected from surfaces of small animal clinical care tables (n =8), cages in the dog and cat hospitalisation sector and animals with infectious diseases (n = 21), small animal surgical centre (n =8), sterilisation sector (n =7) and stethoscopes (n = 32) by using sterile swabs. Bacterial isolation and identification, antimicrobial resistance phenotypic test and molecular detection of antimicrobial resistance, biofilm formation and enterotoxin genes were carried out. Ninety-five bacterial isolates were obtained, and 29 (30.5%) were identified as Staphylococcus spp. Overall, 13 isolates (44.8%) of six species of Staphylococcus spp. showed antimicrobial resistance profile, as well as S. haemolyticus expressed phenotypic profile of multidrug resistance. The antimicrobials with the highest resistance rates were penicillin and tetracycline. The most frequent resistance genes were blaZ and tetM, both detected in 10 (76.9%) isolates. The mecA, tetL and tetK genes had frequencies of 38.5% (5/13), 23.1% (3/13) and 15.4% (2/13), respectively. The biofilm production marker, icaD gene, was detected in one S. sciuri strain. SEE gene, which encodes enterotoxins, was detected in 15.4% (2/13) of the strains (S. pseudintermedius and S. intermedius). The occurrence of Staphylococcus spp. carrying resistance genes to diferent classes of antimicrobials, presenting MDR phenotypic pattern and carrying enterotoxins and biofim encoding genes recovered from veterinary hospital facilities and fomites in the Caatinga biome reinforce the need to implement prevention cares in veterinary practices to avoid One Health-concerning conditions.

Longitudinal viral shedding and antibody response characteristics of men with acute infection of monkeypox virus: a prospective cohort study.

Understanding of infection dynamics is important for public health measures against monkeypox virus (MPXV) infection. Herein, samples from multiple body sites and environmental fomites of 77 acute MPXV infections (HIV co-infection: N = 42) were collected every two to three days and used for detection of MPXV DNA, surface protein specific antibodies and neutralizing titers. Skin lesions show 100% positivity rate of MPXV DNA, followed by rectum (88.16%), saliva (83.78%) and oropharynx (78.95%). Positivity rate of oropharynx decreases rapidly after 7 days post symptom onset (d.p.o), while the rectum and saliva maintain a positivity rate similar to skin lesions. Viral dynamics are similar among skin lesions, saliva and oropharynx, with a peak at about 6 d.p.o. In contrast, viral levels in the rectum peak at the beginning of symptom onset and decrease rapidly thereafter. 52.66% of environmental fomite swabs are positive for MPXV DNA, with highest positivity rate (69.89%) from air-conditioning air outlets. High seropositivity against A29L (100%) and H3L (94.74%) are detected, while a correlation between IgG endpoint titers and neutralizing titers is only found for A29L. Most indexes are similar between HIV and Non-HIV participants, while HIV and rectitis are associated with higher viral loads in rectum.

Multiple pathogen contamination of water, hands, and fomites in rural Nepal and the effect of WaSH interventions.

Water, Sanitation, and Hygiene (WaSH) interventions are the most effective in reducing diarrheal disease severity and prevalence. However, very few studies have investigated the effectiveness of WaSH intervention in reducing pathogen presence and concentration. In this study, we employed a microfluidic PCR approach to quantify twenty bacterial pathogens in water (n = 360), hands (n = 180), and fomite (n = 540) samples collected in rural households of Nepal to assess the pathogen exposures and the effect of WaSH intervention on contamination and exposure rates. The pathogen load and the exposure pathways for each pathogen in intervention and control villages were compared to understand the effects of WaSH intervention. Pathogens were detected in higher frequency and concentration from fomites samples, toilet handle (21.42%; 5.4,0 95%CI: mean log10 of 4.69, 5.96), utensils (23.5%; 5.47, 95%CI: mean log10 of 4.77, 6.77), and water vessels (22.42%; 5.53, 95%CI: mean log10 of 4.79, 6.60) as compared to cleaning water (14.36%; 5.05, 95%CI: mean log10 of 4.36, 5.89), drinking water (14.26%; 4.37, 85%CI: mean log10 of 4.37, 5.87), and hand rinse samples (16.92%; 5.49, 95%CI: mean log10 of 4.77, 6.39). There was no clear evidence that WaSH intervention reduced overall pathogen contamination in any tested pathway. However, we observed a significant reduction (p < 0.05) in the prevalence, but not concentration, of some target pathogens, including Enterococcus spp. in the intervention village compared to the control village for water and hands rinse samples. Conversely, no significant reduction in target pathogen concentration was observed for water and hand rinse samples. In swab samples, there was a reduction mostly in pathogen concentration rather than pathogen prevalence, highlighting that a reduction in pathogen prevalence was not always accompanied by a reduction in pathogen concentration. This study provides an understanding of WaSH intervention on microbe concentrations. Such data could help with better planning of intervention activities in the future.

Transmission of Viruses from Restroom Use: A Quantitative Microbial Risk Assessment.

Restroom use has been implicated in a number of viral outbreaks. In this study, we apply quantitative microbial risk assessment to quantify the risk of viral transmission by contaminated restroom fomites. We estimate risk from high-touch fomite surfaces (entrance/exit door, toilet seat) for three viruses of interest (SARS-CoV-2, adenovirus, norovirus) through eight exposure scenarios involving differing user behaviors, and the use of hand sanitizer following each scenario. We assessed the impacts of several sequences of fomite contacts in the restroom, reflecting the variability of human behavior, on infection risks for these viruses. Touching of the toilet seat was assumed to model adjustment of the seat (open vs. closed), a common touch point in single-user restrooms (home, small business, hospital). A Monte Carlo simulation was conducted for each exposure scenario (10,000 simulations each). Norovirus resulted in the highest probability of infection for all exposure scenarios with fomite surfaces. Post-restroom automatic-dispensing hand sanitizer use reduced the probability of infection for each virus by up to 99.75%. Handwashing within the restroom, an important risk-reduction intervention, was not found to be as effective as use of a non-touch hand sanitizer dispenser for reducing risk to near or below 1/1,000,000, a commonly used risk threshold for comparison.

Inactivation of Three Subtypes of Influenza A Virus by a Commercial Device Using Ultraviolet Light and Ozone.

Avian influenza (AI) is a highly contagious disease that can be transmitted to naïve birds through fomites. The survival of AI viruses (AIV) on nonporous and porous fomites also dictates how long the fomite can serve as a vehicle for virus transmission. AIVs are known to be inactivated by ozone and ultraviolet (UV) light. However, the combined effect of UV light and ozone in combating AIV on different fomites has not been investigated. This study was undertaken to determine AIV inactivation by a commercial device called the BioSec shoe sanitizing station. This device generates both ozone and UV light for 8 sec when activated. We evaluated this device against three different subtypes of AIVs applied on seven different fomites. In general, the device inactivated all three AIV subtypes loaded on all fomites but to varying degrees of inactivation. The percentage of virus reduction on nonporous fomites (98.6%-99.9%) was higher than on porous fomites (90.0%-99.5%). In conclusion, this new device has the potential to help reduce the risk of transmission of AIV.

Inactivación de cuatro subtipos del virus de la influenza A mediante un dispositivo comercial usando luz ultravioleta y ozono. La influenza aviar (IA) es una enfermedad altamente contagiosa que puede transmitirse a aves susceptibles a través de fómites. La supervivencia de los virus de la influenza aviar en fómites porosos y no porosos también determina cuánto tiempo el fómite puede servir como vehículo para la transmisión del virus. Se sabe que los virus de influenza aviar son inactivados por el ozono y la luz ultravioleta (UV). Sin embargo, no se ha investigado el efecto combinado de la luz ultravioleta y el ozono para inactivar el virus de la influenza aviar en diferentes fómites. Este estudio se llevó a cabo para determinar la inactivación del virus de la influenza aviar mediante un dispositivo comercial llamado estación de desinfección de calzado BioSec. Este dispositivo genera ozono y luz ultravioleta durante 8 segundos cuando se activa. Se evaluó este dispositivo frente a cuatro subtipos diferentes del virus influenza aviar aplicados en siete fómites diferentes. En general, el dispositivo inactivó los cuatro subtipos de influenza aviar inoculados en todos los fómites, pero con distintos grados de inactivación. El porcentaje de reducción de virus en fómites no porosos (98.6%­99.9%) fue mayor que en fómites porosos (90.0%­99.5%). En conclusión, este nuevo dispositivo tiene el potencial de ayudar a reducir el riesgo de transmisión del virus de la influenza aviar.

Fluoride anodic films on stainless-steel fomites to reduce transmission infections.

The growing concern arising from viruses with pandemic potential and multi-resistant bacteria responsible for hospital-acquired infections and outbreaks of food poisoning has led to an increased awareness of indirect contact transmission. This has resulted in a renewed interest to confer antimicrobial properties to commonly used metallic materials. The present work provides a full characterization of optimized fluoride anodic films grown in stainless steel 304L as well as their antimicrobial properties. Antibacterial tests show that the anodic film, composed mainly of chromium and iron fluorides, reduces the count and the percentage of the area covered by 50% and 87.7% for Pseudomonas aeruginosa and Stenotrophomonas maltophilia, respectively. Virologic tests show that the same treatment reduces the infectivity of the coronavirus HCoV-229E-GFP, in comparison with the non-anodized stainless steel 304L.IMPORTANCEThe importance of environmental surfaces as a source of infection is a topic of particular interest today, as many microorganisms can survive on these surfaces and infect humans through direct contact. Modification of these surfaces by anodizing has been shown to be useful for some alloys of medical interest. This work evaluates the effect of anodizing on stainless steel, a metal widely used in a variety of applications. According to the study, the fluoride anodic layers reduce the colonization of the surfaces by both bacteria and viruses, thus reducing the risk of acquiring infections from these sources.

Stability of mpox virus on different commonly contacted surfaces.

Mpox is still spreading globally and is mostly reported to be transmitted by skin and mucosal contact. However, transmission through contact with fomites, contaminated objects, or surfaces has been reported in general population. Evaluation of the stability of mpox virus (MPXV) on different surfaces is important to minimize mpox transmission. In the study, the stability of MPXV on different kinds of commonly contacted surfaces was determined. MPXV was observed to have a surface-dependent stability pattern. Viable virus was detected on both glass and stainless steel for up to 5 days, and on plastic surfaces for up to 3 days. In contrast, no viable MPXV was detected on wooden board and cardboard, which are porous and water-absorbent surfaces, after 1 and 2 days of incubation, respectively. In addition, MPXV nucleic acids were more stable and showed better correlation with viral titers on stainless steel, plastic, and glass. The results indicate that fomite transmission of MPXV is plausible. Moreover, the stability of MPXV was highly surface-dependent and more stable on smooth surfaces, which could provide more information for minimizing the transmission of mpox and emphasize the significance of environmental disinfection in mpox prevention and control.

Stability of pathogens on banknotes and coins: A narrative review.

For the prevention of infectious diseases, knowledge about potential transmission routes is essential. Pathogens can be transmitted directly (i.e. respiratory droplets, hand-to-hand contact) or indirectly via contaminated surfaces (fomites). In particular, frequently touched objects/surfaces may serve as transmission vehicles for different clinically relevant bacterial, fungal, and viral pathogens. Banknotes and coins offer ample surface area and are frequently exchanged between individuals. Consequently, many concerns have been raised in the recent past, that banknotes and coins could serve as vectors for the transmission of disease-causing microorganisms. This review summarizes the latest research on the potential of paper currency and coins to serve as sources of pathogenic viral, bacterial, and fungal agents. In contrast to the current perception of banknotes and coins as important transmission vehicles, current evidence suggests, that banknotes and coins do not pose a particular risk of pathogen infection for the public.

Environmental dissemination of respiratory viruses: dynamic interdependencies of respiratory droplets, aerosols, aerial particulates, environmental surfaces, and contribution of viral re-aerosolization.

During the recent pandemic of COVID-19 (SARS-CoV-2), influential public health agencies such as the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) have favored the view that SARS CoV-2 spreads predominantly via droplets. Many experts in aerobiology have openly opposed that stance, forcing a vigorous debate on the topic. In this review, we discuss the various proposed modes of viral transmission, stressing the interdependencies between droplet, aerosol, and fomite spread. Relative humidity and temperature prevailing determine the rates at which respiratory aerosols and droplets emitted from an expiratory event (sneezing, coughing, etc.) evaporate to form smaller droplets or aerosols, or experience hygroscopic growth. Gravitational settling of droplets may result in contamination of environmental surfaces (fomites). Depending upon human, animal and mechanical activities in the occupied space indoors, viruses deposited on environmental surfaces may be re-aerosolized (re-suspended) to contribute to aerosols, and can be conveyed on aerial particulate matter such as dust and allergens. The transmission of respiratory viruses may then best be viewed as resulting from dynamic virus spread from infected individuals to susceptible individuals by various physical states of active respiratory emissions, instead of the current paradigm that emphasizes separate dissemination by respiratory droplets, aerosols or by contaminated fomites. To achieve the optimum outcome in terms of risk mitigation and infection prevention and control (IPAC) during seasonal infection peaks, outbreaks, and pandemics, this holistic view emphasizes the importance of dealing with all interdependent transmission modalities, rather than focusing on one modality.

A comparative study on the persistence and viability of SARS-CoV-2 wild-type and omicron variant on artificially contaminated surfaces: the role of fomites.

Indirect transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been investigated but it is still not completely understood. The present study aimed to compare the persistence and viability of the lineage B.1 and omicron BA.1 subvariant in five daily-use materials to evaluate the role of fomites as a possible source of infection. Artificial contamination was performed in the first set of materials, ethylene vinyl acetate (EVA), cardboard, polystyrene, aluminium, and plastic. Further surfaces using BA.1 (glass, plexiglass, cotton, polyester, and tetrapak) were conducted. The persistence, viability of Vero E6 cell cultures and the residual infectivity of the two lineages were evaluated over 5 days. The results showed different stabilities between the tested matrices. In cotton and polyester, the RNA was undetectable in 24 and 48h post-contamination (p.c.), respectively, and the virus was not viable within 30 min, while in the other surfaces, both lineages, RNA was detectable until 120h p.c. A rapid decay of the viral load was revealed on cardboard, mostly for the omicron variant. Furthermore, on all the materials, longer stability of BA.1 was demonstrated, but showing a less intense CPE than the wild-type. EVA was the material that was able to better sustain virus stability as the virus developed CPE up to 72h p.c. In conclusion, the potential spread of SARS-CoV-2 through fomites is conceivable, albeit it is difficult to establish the real capacity to infect people. Nevertheless, thise information is fundamental to adopting the appropriate measures to mitigate the spread of SARS-CoV-2 and its variants.

Viral Disinfection of Porous Fomites Utilizing a Bacteriophage Model and Chlorine Dioxide Gas.

The pursuit of disinfecting porous materials or fomites to inactivate viral agents has special challenges. To address these challenges, a highly portable chlorine dioxide (ClO2) gas generation system was used to ascertain the ability of a gaseous preparation to inactivate a viral agent, the MS2 bacteriophage, when associated with potentially porous fomites of cloth, paper towel, and wood. The MS2 bacteriophage is increasingly used as a model to identify means of inactivating infectious viral agents of significance to humans. Studies showed that MS2 bacteriophage can be applied to and subsequently recovered from potential porous fomites such as cloth, paper towel, and wood. Paired with viral plaque assays, this provided a means for assessing the ability of gaseous ClO2 to inactivate bacteriophage associated with the porous materials. Notable results include 100% inactivation of 6 log bacteriophage after overnight exposure to 20 parts per million(ppm) ClO2. Reducing exposure time to 90 minutes and gas ppm to lower concentrations proved to remain effective in bacteriophage elimination in association with porous materials. Stepwise reduction in gas concentration from 76 ppm to 5 ppm consistently resulted in greater than 99.99% to 100% reduction of recoverable bacteriophage. This model suggests the potential of ClO2 gas deployment systems for use in the inactivation of viral agents associated with porous potential fomites. The ClO2 gas could prove especially helpful in disinfecting enclosed areas containing viral contaminated surfaces, rather than manually spraying and wiping them.

A narrative review of alternative transmission routes of COVID 19: what we know so far.

The Coronavirus disease 19 (COVID-19) pandemics, caused by severe acute respiratory syndrome coronaviruses, SARS-CoV-2, represent an unprecedented public health challenge. Beside person-to-person contagion via airborne droplets and aerosol, which is the main SARS-CoV-2's route of transmission, alternative modes, including transmission via fomites, food and food packaging, have been investigated for their potential impact on SARS-CoV-2 diffusion. In this context, several studies have demonstrated the persistence of SARS-CoV-2 RNA and, in some cases, of infectious particles on exposed fomites, food and water samples, confirming their possible role as sources of contamination and transmission. Indeed, fomite-to-human transmission has been demonstrated in a few cases where person-to-person transmission had been excluded. In addition, recent studies supported the possibility of acquiring COVID-19 through the fecal-oro route; the occurrence of COVID-19 gastrointestinal infections, in the absence of respiratory symptoms, also opens the intriguing possibility that these cases could be directly related to the ingestion of contaminated food and water. Overall, most of the studies considered these alternative routes of transmission of low epidemiological relevance; however, it should be considered that they could play an important role, or even be prevalent, in settings characterized by different environmental and socio-economic conditions. In this review, we discuss the most recent findings regarding SARS-CoV-2 alternative transmission routes, with the aim to disclose what is known about their impact on COVID-19 spread and to stimulate research in this field, which could potentially have a great impact, especially in low-resource contexts.