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1.
Infect Control Hosp Epidemiol ; : 1-10, 2022 Feb 28.
Article in English | MEDLINE | ID: covidwho-2323929

ABSTRACT

The risk factors of environmental contamination by SARS-CoV-2 were unknown. We analyzed 1,320 environmental samples obtained from COVID-19 patients for 1 year. The risk factors of contamination of COVID-19 patients' surrounding environment were higher viral load in the respiratory tract and shorter duration from symptom onset to sample collection.

2.
Int J Environ Res Public Health ; 20(8)2023 04 07.
Article in English | MEDLINE | ID: covidwho-2299469

ABSTRACT

Surfaces have been implicated in the transmission of pathogens in hospitals. This study aimed to assess the effectiveness of an usnic-acid-containing self-decontaminating coating in reducing microbial surface contamination in tertiary-care hospitals. Samples were collected from surfaces 9 days before coating application, and 3, 10, and 21 days after its application (phases 1, 2, 3, and 4, respectively). Samples were tested for bacteria, fungi, and SARS-CoV2. In phase 1, 53/69 (76.8%) samples tested positive for bacteria, 9/69 (13.0%) for fungi, and 10/139 (7.2%) for SARS-CoV-2. In phase 2, 4/69 (5.8%) samples tested positive for bacteria, while 69 and 139 samples were negative for fungi and SARS-CoV-2, respectively. In phase 3, 3/69 (4.3%) samples were positive for bacteria, 1/139 (0.7%) samples tested positive for SARS-CoV-2, while 69 samples were negative for fungi. In phase 4, 1/69 (1.4%) tested positive for bacteria, while no fungus or SARS-CoV-2 were detected. After the coating was applied, the bacterial load was reduced by 87% in phase 2 (RR = 0.132; 95% CI: 0.108-0.162); 99% in phase 3 (RR = 0.006; 95% CI: 0.003-0.015); and 100% in phase 4 (RR = 0.001; 95% CI: 0.000-0.009). These data indicate that the usnic-acid-containing coating was effective in eliminating bacterial, fungal, and SARS-CoV-2 contamination on surfaces in hospitals.Our findings support the benefit ofan usnic-acid-containing coating in reducing the microbial load on healthcare surfaces.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/epidemiology , COVID-19/prevention & control , RNA, Viral , Tertiary Care Centers
3.
Sci Total Environ ; 881: 163322, 2023 Jul 10.
Article in English | MEDLINE | ID: covidwho-2295234

ABSTRACT

International high-risk clones of Klebsiella pneumoniae are important human pathogens that are spreading to the environment. In the COVID-19 pandemic scenario, the frequency of carbapenemase-producing strains increased, which can contribute to the contamination of the environment, impacting the surrounding and associated ecosystems. In this regard, KPC-producing strains were recovered from aquatic ecosystems located in commercial, industrial, or agricultural areas and were submitted to whole-genome characterization. K. pneumoniae and Klebsiella quasipneumoniae subsp. quasipneumoniae strains were assigned to high-risk clones (ST11, ST340, ST307) and the new ST6325. Virulome analysis showed genes related to putative hypervirulence. Strains were resistant to almost all antimicrobials tested, being classified as extensively drug-resistant or multidrug-resistant. In this context, a broad resistome (clinically important antimicrobials and hazardous metal) was detected. Single replicon (IncX5, IncN-pST15, IncU) and multireplicon [IncFII(K1)/IncFIB(pQil), IncFIA(HI1)/IncR] plasmids were identified carrying the blaKPC-2 gene with Tn4401 and non-Tn4401 elements. An unusual association of blaKPC-2 and qnrVC1 and the coexistence of blaKPC-2 and mer operon (mercury tolerance) was found. Comparative analysis revealed that blaKPC-2-bearing plasmids were most similar to plasmids from Enterobacterales of Brazil, China, and the United States, evidencing the long persistence of plasmids at the human-animal-environmental interface. Furthermore, the presence of uncommon plasmids, displaying the interspecies, intraspecies, and clonal transmission, was highlighted. These findings alert for the spread of high-risk clones producing blaKPC-2 in the environmental sector and call attention to rapid dispersion in a post-pandemic world.


Subject(s)
COVID-19 , Klebsiella Infections , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , beta-Lactamases/genetics , Clone Cells , Ecosystem , Klebsiella Infections/epidemiology , Klebsiella pneumoniae/genetics , Microbial Sensitivity Tests , Pandemics , Plasmids/genetics
4.
Mathematical Methods in the Applied Sciences ; 2023.
Article in English | Scopus | ID: covidwho-2267488

ABSTRACT

The emergence of COVID-19 pandemic has been a major social as well as economic challenges around the globe. Infections from the infected surfaces have also been identified as drivers of COVID-19 transmission, but most of the epidemic models do not include the effect of environmental contamination to account for the indirect transmission of the disease. The present study is devoted to the investigation of the effect of environmental contamination on the spread of the coronavirus pandemic by means of a mathematical model. We also consider the impact of vaccination coverage as an effective control measure against COVID-19. The proposed model is analyzed to discuss the feasibility as well as stability of the disease-free and endemic equilibria;an epidemic threshold in the form of basic reproduction number is obtained. Further, we incorporate the effect of seasonal periodic changes by letting the rate of direct transmission of disease as time dependent, and find sufficient conditions for the global attractivity of the positive periodic solution. We employ sophisticated techniques of sensitivity analysis to identify model parameters which significantly alter the epidemic threshold and the disease prevalence. We find that by enhancing the vaccination of the susceptible population and hospitalization of the symptomatic/asymptomatic individuals, the basic reproduction number can be lowered to a value less than unity. The findings show that the prevalence of disease can be potentially suppressed by increasing the vaccination of susceptible population, hospitalization of infected people and depletion of environmental contamination. Moreover, we observe that seasonal pattern in the disease transmission causes persistence of the pandemic in the population for a longer period. © 2023 John Wiley & Sons, Ltd.

5.
Erciyes Medical Journal / Erciyes Tip Dergisi ; 45(2):203-206, 2023.
Article in English | Academic Search Complete | ID: covidwho-2265851

ABSTRACT

Although droplets and aerosol are considered the main transmission routes of SARS-CoV-2, indirect contact has been indicated to play a critical role in transmission. The aim of this study is to evaluate the presence of SARS-CoV-2 RNA on different environmental surfaces in public areas in Cyprus. Using RT-qPCR, samples from 50 swab specimens collected from high-touch surfaces were analyzed for viral RNA. Six surfaces (12.0%) in all were positive for SARS-CoV-2. Among the examined surfaces within supermarkets, SARS-CoV-2 was detected in 22.2% (n=4/18) of the sampling points, with shopping trolley handles and POS keyboards being the most frequently contaminated items. In the hospital setting, two (n=2/5, 40%) samples were positive for SARS-CoV-2. Our results indicate that, at the current stage of the pandemic, viral contamination of public spaces exists in the community. Lifting protective measures may have contributed to fomite transmission in public spaces. [ FROM AUTHOR] Copyright of Erciyes Medical Journal / Erciyes Tip Dergisi is the property of KARE Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

6.
China Tropical Medicine ; 22(12):1184-1187, 2022.
Article in Chinese | Scopus | ID: covidwho-2286148

ABSTRACT

Objective To analyze the detection of SARS-CoV-2 in household environment and public place environment of Huangpu District, and describe the feature of SARS-CoV-2 contamination in the environment exposure to the infected cases, so as to support the control strategies such as disinfection and health communication. Methods The results of RT-PCR test for the environmental samples exposure to the cases infected by SARS-CoV-2 during February 1 to March 31 2022 in Huangpu District of Shanghai were collected as the research data. Pearson χ2 was used to test the significance of the differences between positive rates of SARS-CoV-2 contamination. Results From February 1 to March 31, household environment samples had a higher positive rate (6.47%, 234/3 618) of SARS-CoV-2 contamination while the public place samples had a lower one (1.22%, 47/3 582) in Huangpu District of Shanghai (χ2=141.908, P<0.01). Among the household buildings, the lane houses of old style representing poorer living condition had the highest positive rates (8.31%, 96/1 155) of SARS-CoV-2 contamination while the apartments representing better living condition had the lowest (3.59%, 22/612) (F=5.25 P<0.05). Among the samples from household environment, samples regarding sewerage had the highest positive rates (13.30%, 58/436) of SARS-CoV-2 contamination, while samples regarding the tool of cooking and sweeping had the lowest (3.10%, 17/548) (F=9.84 P<0.01). Among the samples from public place environment, samples regarding entertainment tools had the highest positive rates (13.33%, 2/15) of SARS-CoV-2 contamination, while samples regarding the tool of cooking and sweeping had the lowest (0.62%, 4/646) (F=4.22 P<0.01). Conclusion In the environment exposure to the SARS-CoV-2 infected cases, the disinfection, ventilation and cleaning should be intensified strictly. SARS-CoV-2's surviving in sewage environment should be evaluation dynamically. More health communication should be pushed to people of poorer living condition. © 2022 Editorial Office of Chinese Journal of Schistosomiasis Control. All rights reserved.

7.
Am J Infect Control ; 51(4): 413-419, 2023 04.
Article in English | MEDLINE | ID: covidwho-2286440

ABSTRACT

BACKGROUND: Temporary isolation wards have been introduced to meet demands for airborne-infection-isolation-rooms (AIIRs) during the COVID-19 pandemic. Environmental sampling and outbreak investigation was conducted in temporary isolation wards converted from general wards and/or prefabricated containers, in order to evaluate the ability of such temporary isolation wards to safely manage COVID-19 cases over a period of sustained use. METHODS: Environmental sampling for SARS-CoV-2 RNA was conducted in temporary isolation ward rooms constructed from pre-fabricated containers (N = 20) or converted from normal-pressure general wards (N = 47). Whole genome sequencing (WGS) was utilized to ascertain health care-associated transmission when clusters were reported amongst HCWs working in isolation areas from July 2020 to December 2021. RESULTS: A total of 355 environmental swabs were collected; 22.4% (15/67) of patients had at least one positive environmental sample. Patients housed in temporary isolation ward rooms constructed from pre-fabricated containers (adjusted-odds-ratio, aOR = 10.46, 95% CI = 3.89-58.91, P = .008) had greater odds of detectable environmental contamination, with positive environmental samples obtained from the toilet area (60.0%, 12/20) and patient equipment, including electronic devices used for patient communication (8/20, 40.0%). A single HCW cluster was reported amongst staff working in the temporary isolation ward constructed from pre-fabricated containers; however, health care-associated transmission was deemed unlikely based on WGS and/or epidemiological investigations. CONCLUSION: Environmental contamination with SARS-CoV-2 RNA was observed in temporary isolation wards, particularly from the toilet area and smartphones used for patient communication. However, despite intensive surveillance, no healthcare-associated transmission was detected in temporary isolation wards over 18 months of prolonged usage, demonstrating their capacity for sustained use during succeeding pandemic waves.


Subject(s)
COVID-19 , Humans , SARS-CoV-2 , Pandemics , RNA, Viral , Hospitals
8.
Cureus ; 15(1): e34136, 2023 Jan.
Article in English | MEDLINE | ID: covidwho-2267497

ABSTRACT

Background The coronavirus disease 2019 (COVID-19) pandemic is a global concern and has changed the way we practice medicine in acute hospital settings. This is particularly true with regard to patient triage, patient risk assessment, use of personal protective equipment, and environmental disinfection. Transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is primarily through inhalation of respiratory droplets generated through talking, coughing, or sneezing. There is, however, a potential risk that respiratory droplets settling on inanimate surfaces and objects in the hospital environment could provide a reservoir for nosocomial infections in patients and pose a healthcare risk to medical staff. Indeed, there have been previous reports of healthcare-associated outbreaks in hospitals. Several authors have argued that the risk of transmission via fomites may be insignificant. It is, however, not clear what proportion of SARS-CoV-2 infections are attributable to direct contact with fomites; a few reports have indicated possible transmission via this route. Environmental contamination with SARS-CoV-2 in healthcare institutions has been shown to vary according to the function or service provided by a unit or department. Information that identifies hospital areas that have a propensity for higher environmental burden may improve the practice of infection control and environmental cleaning and decontamination in healthcare institutions. This study aimed to investigate environmental SARS-CoV-2 contamination in the clinical areas of patients with COVID-19 infection. Methodology We conducted a cross-sectional study performing swabbing of frequently touched surfaces, equipment, and ventilation ducts in five specific clinical areas of Peterborough City Hospital which is part of the North West Anglia NHS Foundation Trust. The five clinical areas that were chosen for swabbing were the Emergency Department (ED), Intensive Care Unit (ICU), Isolation Ward, Respiratory Ward, and a Gastroenterology Ward that was serving as a receiving ward at the height of the second COVID-19 infection wave in the United Kingdom. Surfaces to be swabbed were divided into the patient zone, doctor zone, and nursing zone. Swabs from the chosen surfaces were collected on two consecutive days. A total of 158 surface swabs were collected during the second wave of the COVID-19 pandemic. SARS-CoV-2 RNA was detected by reverse transcription polymerase chain reaction. Results The most contaminated clinical areas were the three receiving wards where 12% (11/96) of the swabs were positive. Inside the patient rooms, these surfaces included bed rails and controls, bedside tables, television screens, remote control units, and the room ventilation system. Outside the patient room, these surfaces included mobile computers and computer desk surfaces in the doctors' offices. All swabs taken from the ED and ICU were found to be negative. Conclusions Our study confirms the potential infection risks posed by environmental contamination with the SARS-CoV-2 virus. This highlights the importance of adequate environmental cleaning for proper infection control and prevention in healthcare settings.

9.
J Infect Chemother ; 29(6): 604-609, 2023 Jun.
Article in English | MEDLINE | ID: covidwho-2271293

ABSTRACT

BACKGROUND: Although crowds are considered to be a risk factor for SARS-CoV-2 transmission, little is known about the changes in environmental surface contamination with the virus when a large number of people attend an event. In this study, we evaluated the changes in environmental surface contamination with SARS-CoV-2. METHODS: Environmental samples were collected from concert halls and banquet rooms before and after events in February to April 2022 when the 7-day moving average of new COVID-19 cases in Tokyo was reported to be 5000-18000 cases per day. In total, 632 samples were examined for SARS-CoV-2 by quantitative reverse transcription polymerase chain reaction (RT-qPCR) tests, and RT-qPCR-positive samples were subjected to a plaque assay. RESULTS: The SARS-CoV-2 RNA detection rate before and after the events ranged from 0% to 2.6% versus 0%-5.0% in environmental surface samples, respectively. However, no viable viruses were isolated from all RT-qPCR-positive samples by the plaque assay. There was no significant increase in the environmental surface contamination with SARS-CoV-2 after these events. CONCLUSIONS: These findings revealed that indirect contact transmission from environmental fomite does not seem to be of great magnitude in a community setting.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/epidemiology , RNA, Viral/genetics , Japan/epidemiology , Risk Factors
10.
Am J Infect Control ; 2022 Nov 23.
Article in English | MEDLINE | ID: covidwho-2246553

ABSTRACT

BACKGROUND: Fangcang shelter hospitals emerged as a new public health concept after COVID-19. Data regarding contamination of Fangcang shelter environments remains scarce. This study aims to investigate the extent of SARS-CoV-2 contamination on personal protective equipment and surfaces in Fangcang hospitals. METHODS: Between March and May 2022, during wave of omicron variant, a prospective study was conducted in two Fangcang hospitals in Shanghai, China. Swabs of personal protective equipment worn and environmental surfaces of contaminated areas, doffing rooms, and potentially contaminated areas were collected. SARS-CoV-2 RNA was detected by reverse transcription quantitative polymerase chain reaction. If viral RNA was detected, sampling was repeated after cleaning and disinfection. RESULTS: A total of 602 samples were collected. 13.3% of the personal protective equipment were contaminated. Positive rate was higher in the contaminated areas (48.4%) than in the doffing rooms (11.7%) and the potentially contaminated areas (0; P<0.05). Contamination was highest in patient occupied areas 67.5%. After cleaning, samples taken at previously contaminated surfaces are all negative. CONCLUSIONS: SARS-CoV-2 RNA contamination is prevalent in Fangcang hospitals and healthcare workers are under risk of infection. Potentially contaminated areas and surfaces after cleaning and disinfection are negative, underlying the importance of infection control policy.

12.
mSphere ; 5(3)2020 06 24.
Article in English | MEDLINE | ID: covidwho-2193484

ABSTRACT

The contamination of patients' surroundings by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains understudied. We sampled the surroundings and the air of six negative-pressure non-intensive care unit (non-ICU) rooms in a designated isolation ward in Chengdu, China, that were occupied by 13 laboratory-confirmed coronavirus disease 2019 (COVID-19) patients who had returned from overseas travel, including 2 asymptomatic patients. A total of 44 of 112 (39.3%) surface samples were positive for SARS-CoV-2 as detected by real-time PCR, suggesting extensive contamination, although all of the air samples were negative. In particular, in a single room occupied by an asymptomatic patient, four sites were SARS-CoV-2 positive, highlighting that asymptomatic COVID-19 patients do contaminate their surroundings and impose risks for others with close contact. Placement of COVID-19 patients in rooms with negative pressure may bring a false feeling of safety, and the importance of rigorous environment cleaning should be emphasized.IMPORTANCE Although it has been well recognized that the virus SARS-CoV-2, the causative agent of COVID-19, can be acquired by exposure to fomites, surprisingly, the contamination of patients' surroundings by SARS-CoV-2 is largely unknown, as there have been few studies. We performed an environmental sampling study for 13 laboratory-confirmed COVID-19 patients and found extensive contamination of patients' surroundings. In particular, we found that asymptomatic COVID-19 patients contaminated their surroundings and therefore imposed risks for other people. Environment cleaning should be emphasized in negative-pressure rooms. The findings may be useful to guide infection control practice to protect health care workers.


Subject(s)
Asymptomatic Infections/epidemiology , Betacoronavirus/isolation & purification , Coronavirus Infections/epidemiology , Environmental Exposure , Environmental Microbiology , Pneumonia, Viral/epidemiology , COVID-19 , Containment of Biohazards/methods , Coronavirus Infections/pathology , Environment , Humans , Pandemics , Pneumonia, Viral/pathology , SARS-CoV-2
13.
Int J Environ Res Public Health ; 20(2)2023 Jan 05.
Article in English | MEDLINE | ID: covidwho-2166552

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and resulting COVID-19 (coronavirus disease 2019) pandemic have required mass diagnostic testing, often taking place in testing sites within hospitals, clinics, or at satellite locations. To establish the potential of SARS-CoV-2 aerosol transmission and to identify junctures during testing that result in increased viral exposure, aerosol and surface samples were examined for the presence of SARS-CoV-2 RNA from locations within Nebraska Medicine COVID-19 testing and vaccine clinics. Aerosols containing SARS-CoV-2 RNA detected within clinics suggest viral shedding from infected individuals. SARS-CoV-2 RNA detection in aerosol samples was shown to correlate with clinic operation and patient infection, as well as with community infection findings. Additionally, SARS-CoV-2 RNA was detected in surface samples collected from clinics. The presence of SARS-CoV-2 RNA in aerosols in these clinics supports the continued use of respiratory protection and sanitization practices for healthcare workers, and other workers with public facing occupations.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19 Testing , RNA, Viral , Respiratory Aerosols and Droplets
14.
Journal of Hazardous Materials Advances ; : 100217, 2022.
Article in English | ScienceDirect | ID: covidwho-2158889

ABSTRACT

The unprecedented situation of the COVID-19 pandemic heavily polluted water bodies whereas the presence of SARS-CoV-2, even in treated wastewater in every corner of the world is reported. The main aim of the present study is to show the effectiveness and feasibility of some well-known desalination technologies which are reverse osmosis (RO), Electrodialysis (ED), Membrane Distillation (MD), multi effect distillation (MED), and multi stage flashing (MSF) during the COVID-19 pandemic. Systems' effectiveness against the novel coronavirus based on three parameters of nasopharynx/nasal saline-irrigation, temperature of operation and pretreatment methods are evaluated. First, based on previous clinical studies, it showed that using saline solution (hypertonic saline >0.9% concentration) for gargling/irrigating of nasal/nasopharynx/throat results in reducing and replication of the viral in patients, subsequently the feed water of desalination plants which has concentration higher than 3.5% (35000ppm) is preventive against the SARS-CoV-2 virus. Second, the temperature operation of thermally-driven desalination;MSF and MED (70-120°C) and MD (55-85°C) is high enough to inhibit the contamination of plant structure and viral survival in feed water. The third factor is utilizing various pretreatment process such as chlorination, filtration, thermal/precipitation softening, ultrafiltration (mostly for RO, but also for MD, MED and MSF), which are powerful treatment methods against biologically-contaminated feed water particularly the SARS-CoV-2. Eventually, it can be concluded that large-scale desalination plants during COVID-19 and similar situation are completely reliable for providing safe drinking water.

15.
Front Public Health ; 10: 963999, 2022.
Article in English | MEDLINE | ID: covidwho-2163167

ABSTRACT

Background: Using daily monitoring of environmental surfaces and personal protective equipment (PPE), we found an increase in environmental contamination since August 18, 2021, in a designated hospital for COVID-19 patients in China, which may lead to an increased risk of exposure to medical staff. Methods: To investigate the cause of increased environmental contamination and effect of our intervention, we obtained environmental samples at pre-intervention (August 18-21, 2021) and post-intervention (August 22-28, 2021) from six infection isolation rooms with windows for ventilation and other auxiliary areas at 105 and 129 sites before routine daily cleaning, respectively. In addition, we obtained PPE samples from 98 medical staff exiting the patient rooms/contaminated areas at 482 sites. Between August 22 and 24, 2021, we took measures to reduce environmental contamination based on sampling and inspection results. Findings: At pre-intervention, the positivity rates for contamination of environmental surfaces and PPE samples were significantly higher for critical patients (37.21 and 27.86%, respectively) than severely ill patients (25.00 and 12.50%, respectively) and moderately ill patients (0.00 and 0.00%, respectively) (Pearson's Chi-square: χ2 = 15.560, p = 0.000; Fisher's exact test: χ2 = 9.358, p = 0.007). Therefore, we inferred that the source of contamination of environmental surfaces and PPE was mainly the room of critically ill patients, likely through the hands of medical staff to the potentially contaminated areas. A critically ill patient had emergency tracheal intubation and rescue on August 18, 2021, due to worsened patient condition. The ventilator tube used for first aid did not match the ventilator, and the ventilator tube fell off multiple times on August 18-21, 2021, which may explain the increased contamination of environmental surfaces and PPE from critically ill patients, as well as lead to indirect contamination of potentially contaminated areas. The contamination positivity rates of environmental surfaces and PPE were reduced by replacing the appropriate ventilator catheter, limiting the number of people entering the isolation room simultaneously, increasing the frequency of environmental disinfection, standardizing the undressing process, setting up undressing monitoring posts to supervise the undressing process, and preventing the spread of virus infections in the hospital during an epidemic. Conclusions: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was spread on object surfaces in isolation rooms mainly by touch, and the contamination of environmental surfaces and PPE was greater in rooms of patients with greater disease severity and higher surface touch frequency. Therefore, strict protective measures for medical staff, frequent environmental cleaning for isolation rooms, and compliance with mask wearing by patients when conditions permit should be advised to prevent SARS-CoV-2 spread in hospitals.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/epidemiology , COVID-19/prevention & control , Critical Illness , Hospitals , Medical Staff
16.
Heliyon ; 8(11): e11513, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-2116308

ABSTRACT

COVID-19 is one of the greatest human global health challenges that causes economic meltdown of many nations. In this study, we develop an SIR-type model which captures both human-to-human and environment-to-human-to-environment transmissions that allows the recruitment of corona viruses in the environment in the midst of booster vaccine program. Theoretically, we prove some basic properties of the full model as well as investigate the existence of SARS-CoV-2-free and endemic equilibria. The SARS-CoV-2-free equilibrium for the special case, where the constant inflow of corona virus into the environment by any other means, Ω is suspended ( Ω = 0 ) is globally asymptotically stable when the effective reproduction number R 0 c < 1 and unstable if otherwise. Whereas in the presence of free-living Corona viruses in the environment ( Ω > 0 ), the endemic equilibrium using the centre manifold theory is shown to be stable globally whenever R 0 c > 1 . The model is extended into optimal control system and analyzed analytically using Pontryagin's Maximum Principle. Results from the optimal control simulations show that strategy E for implementing the public health advocacy, booster vaccine program, treatment of isolated people and disinfecting or fumigating of surfaces and dead bodies before burial is the most effective control intervention for mitigating the spread of Corona virus. Importantly, based on the available data used, the study also revealed that if at least 70% of the constituents followed the aforementioned public health policies, then herd immunity could be achieved for COVID-19 pandemic in the community.

17.
Microorganisms ; 10(11)2022 Nov 11.
Article in English | MEDLINE | ID: covidwho-2110185

ABSTRACT

(1) Background: Surfaces have been implicated in the transmission of infections. We aimed to assess how effective an usnic-acid-containing self-decontaminating coating was on the surfaces of the Athens underground metro. (2) Methods: Two samples were collected from each of 60 surfaces of a station and a wagon before the application of the coating and 9 and 20 days after, and they were tested for bacteria, fungi, and SARS-CoV-2 using conventional microbiological and molecular methods. Bacteria and fungi growth were expressed in colony forming units (CFUs)/102cm2. (3) Results: Before the application of the coating, 50% of the samples tested positive for the targeted microbes: 91.7% for bacteria, 18.3% for fungi, and 8.3% for SARS-CoV-2. After nine days, 3.3% of the samples tested positive for bacteria and 6.6% after 20 days. The average amount of bacteria before the coating was applied was 8.5 CFU/102cm2 compared to 0 and 0 CFU/102cm2 after application (100% and 95% reduction); all samples collected after the application were negative for SARS-CoV-2 and fungi (100% reduction). (4) Conclusion: An usnic-acid-containing self-decontaminating coating was highly effective in eliminating bacterial, fungal, and SARS-CoV-2 contamination of surfaces in the underground metro.

18.
Iran J Microbiol ; 14(5): 617-623, 2022 Oct.
Article in English | MEDLINE | ID: covidwho-2091173

ABSTRACT

Background and Objectives: Coronavirus disease 2019 (COVID-19) is a pandemic caused by the novel virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Knowing the virus's behavior and its persistence in different environments are crucial and will lead to the proper management of the disease. In this study, air, surface, and sewage samples were taken from different parts of referral hospitals for COVID-19. Materials and Methods: Air samples were taken with impinger, surface samples with swabs, and sewage samples were taken from the hospital wastewater treatment plant. After viral genome extraction, a real-time RT-PCR test was applied to confirm the presence of SARS-CoV-2 RNA in the collected samples. Results: The virus genome could be traced in the wards and wastewater related to hospitalized COVID-19 patients. Overally, 29%, 16%, and 37.5% of air, surface, and sewage samples were positive for the SARS-CoV-2 genome, respectively. Conclusion: Findings of such studies provide valuable results regarding the degree of contamination of hospital environments and the risk of virus transmission in different environments and among hospital staff and patients.

19.
Am J Infect Control ; 50(8): 909-915, 2022 08.
Article in English | MEDLINE | ID: covidwho-2000212

ABSTRACT

BACKGROUND: This study aims to describe the effect of Dry Hydrogen Peroxide (DHP), as an adjunct to environmental cleaning and disinfection, on the incidence of hospital-acquired infections (HAIs) at Unidad Nacional de Oncologia Pediatrica (UNOP) in Guatemala City, Guatemala. METHODS: A retrospective study of all HAI data from the hospital's surveillance system, which follows Centers for Disease Control and Prevention (CDC) protocols, was conducted from January 2019 to November 2020. DHP was installed in all Pediatric Intensive Care Unit (PICU) rooms in January 2020, but nowhere else in the hospital, including the Intermediate Care Unit (IMCU). RESULTS: There were 189 HAI cases during the study period, with 173 occurring in either the PICU or IMCU. A statistically significant decrease in HAI incidence rates occurred in the PICU in 2020 compared to 2019 (P = .028), including Clostridiodes-associated gastroenteritis (P = .048). Logistic multivariate regression yielded a significant association between DHP exposure and reduced odds of developing an HAI during the study (OR = 0.3857, P = .029). CONCLUSION: The use of DHP as an adjunct technology for environmental cleaning and disinfection contributed to the reduction in HAIs in the PICU. Our study highlights the value of such an approach as an addition to manual cleaning to decrease the risk of infection from environmental contamination.


Subject(s)
Cross Infection , Neoplasms , Child , Cross Infection/epidemiology , Cross Infection/prevention & control , Hospitals, Pediatric , Humans , Hydrogen Peroxide , Retrospective Studies
20.
Ecotoxicol Environ Saf ; 241: 113740, 2022 Aug.
Article in English | MEDLINE | ID: covidwho-1944829

ABSTRACT

Air and surface contamination of the SARS-CoV-2 have been reported by multiple studies. However, the evidence is limited for the change of environmental contamination of this virus in the surrounding of patients with COVID-19 at different time points during the course of disease and under different conditions of the patients. Therefore, this study aims to understand the risk factors associated with the appearance of SARS-CoV-2 through the period when the patients were staying in the isolation wards. In this study, COVID-19 patients admitted to the isolation wards were followed up for up to 10 days for daily collection of air and surface samples in their surroundings. The positivity rate of the environmental samples at different locations was plotted, and multiple multi-level mixed-effect logistic regressions were used to examine the association between the positivity of environmental samples and their daily health conditions and environmental factors. It found 6.6 % of surface samples (133/2031 samples) and 2.1 % of air samples (22/1075 samples) were positive, and the positivity rate reached to peak during 2-3 days after admission to the ward. The virus was more likely to present at bedrail, patients' personal items and medical equipment, while less likely to be detected in the air outside the range of 2 m from the patients. It also revealed that higher positivity rate is associated with lower environmental temperature, fever and cough at the day of sampling, lower Ct values of latest test for respiratory tract samples, and pre-existing respiratory or cardiovascular conditions. The finding can be used to guide the hospital infection control strategies by identifying high-risk areas and patients. Extra personal hygiene precautions and equipment for continuously environmental disinfection can be used for these high-risk areas and patients to reduce the risk of hospital infection.


Subject(s)
COVID-19 , Cross Infection , Air Microbiology , COVID-19/epidemiology , COVID-19/prevention & control , Cross Infection/prevention & control , Disinfection , Environment , Equipment Contamination , Hospitals , Humans , Infection Control , SARS-CoV-2
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