scholarly journals Airflow as a Possible Transmission Route of Middle East Respiratory Syndrome at an Initial Outbreak Hospital in Korea

2018 ◽  
Vol 15 (12) ◽  
pp. 2757 ◽  
Author(s):  
Minki Sung ◽  
Seongmin Jo ◽  
Sang-Eun Lee ◽  
Moran Ki ◽  
Bo Choi ◽  
...  
Keyword(s):  
Middle East ◽  
Infected Patient ◽  
Close Contact ◽  
Middle East Respiratory Syndrome ◽  
High Concentration ◽  
Tracer Gas ◽  
Long Distance ◽  
Indoor Airflow ◽  
Change Rate ◽  
Air Change Rate

In this study, the results of an airflow investigation conducted on 7 June 2015 as part of a series of epidemiologic investigations at Pyeongtaek St. Mary’s Hospital, South Korea, were investigated. The study involved 38 individuals who were infected directly and indirectly with Middle East Respiratory Syndrome (MERS), by a super-spreader patient. Tracer gas experiments conducted on the eighth floor, where the initial patient was hospitalized, confirmed that the tracer gas spread to adjacent patient rooms and rooms across corridors. In particular, the experiment with an external wind direction and speed similar to those during the hospitalization of the initial patient revealed that the air change rate was 17–20 air changes per hour (ACH), with air introduced through the window in the room of the infected patient (room 8104). The tracer gas concentration of room 8110, which was the farthest room, was 7.56% of room 8104, indicating that a high concentration of gas has spread from room 8104 to rooms across the corridor. In contrast, the tracer gas was barely detected in a maternity ward to the south of room 8104, where there was no secondary infected patient. Moreover, MERS is known to spread mainly by droplets through close contact, but long-distance dispersion is probable in certain environments, such as that of a super-spreader patient hospitalized in a room without ventilation, hospitals with a central corridor type, and indoor airflow dispersion due to external wind.

scholarly journals Ventilation of general hospital wards for mitigating infection risks of three kinds of viruses including Middle East respiratory syndrome coronavirus

2016 ◽  
Vol 26 (4) ◽  
pp. 514-527 ◽  
Author(s):  
H.C. Yu ◽  
K.W. Mui ◽  
L.T. Wong ◽  
H.S. Chu
Keyword(s):  
Middle East ◽  
General Hospital ◽  
Cfd Simulation ◽  
Middle East Respiratory Syndrome ◽  
Risk Of Infection ◽  
Design Strategies ◽  
Change Rate ◽  
Virus Removal ◽  
Air Change Rate ◽  
Hospital Wards

This study investigates the effectiveness of ventilation design strategies for general hospital wards in terms of virus removal capacity. A typical semi-enclosed six-bed general ward of Hong Kong hospitals and three respiratory viruses, namely Middle East respiratory syndrome coronavirus (MERS- CoV), severe acute respiratory syndrome coronavirus (SARS- CoV) and H1N1 influenza virus, were chosen for the computational fluid dynamics (CFD) simulation of airflow field and virus dispersion inside the ward. The results demonstrated that the location of an infected patient would affect the infection risks to other occupants and healthcare workers inside the same hospital ward, and an increased air change rate in the ward could reduce the risk of infection from direct contact and inhalation. It was found that an air change rate of 9 h−1 could effectively minimize the deposition and floating time of respiratory virus particles while maximizing energy efficiency. This study should provide a useful source of reference for the hospital management to mitigate the risk of infection with MERS or other airborne transmitted viruses through better ventilation design strategies.

scholarly journals Airflow analysis of Pyeongtaek St Mary's Hospital during hospitalization of the first Middle East respiratory syndrome patient in Korea

2019 ◽  
Vol 6 (3) ◽  
pp. 181164 ◽  
Author(s):  
Seongmin Jo ◽  
Jinkwan Hong ◽  
Sang-Eun Lee ◽  
Moran Ki ◽  
Bo Youl Choi ◽  
...  
Keyword(s):  
Middle East ◽  
Close Contact ◽  
Index Patient ◽  
Tracer Diffusion ◽  
Middle East Respiratory Syndrome ◽  
Passive Tracer ◽  
Indoor Airflow ◽  
Epidemiological Surveys ◽  
Study Results ◽  
Poor Ventilation

Middle East respiratory syndrome (MERS) is known to be transmitted through close contact. However, epidemiological surveys of MERS in Korea indicated that some secondary patients were infected without close contact. Therefore, the possibility of other transmission routes must be identified. In this study, the possibility of MERS spreading through airflow was investigated on the eighth floor of Pyeongtaek St Mary's Hospital. Computational fluid dynamics was used to analyse the indoor airflow and passive tracer diffusion during the index patient's stay. Six cases were simulated for different outdoor wind directions and indoor mechanical ventilation operations. When a passive tracer was released in ward 8104, where the index patient was hospitalized, the passive tracer spread through the indoor airflow, which was created by the outdoor airflow. Ward 8109, which had the largest number of infected cases and was far distant from ward 8104, showed passive tracer concentration in all cases. This result indicates that MERS may have spread through airflow. The study results do not imply that the infection pathway of MERS is airborne. However, the results show the possibility of MERS spreading through airflow in specific environments such as poor ventilation environments.

Numerical investigation of wind-driven natural ventilation performance in a multi-storey hospital by coupling indoor and outdoor airflow

2016 ◽  
Vol 25 (8) ◽  
pp. 1226-1247 ◽  
Author(s):  
Ruiqiu Jin ◽  
Jian Hang ◽  
Shanshan Liu ◽  
Jianjian Wei ◽  
Yang Liu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Ventilation ◽  
Tracer Gas ◽  
Indoor Airflow ◽  
Change Rate ◽  
Air Change Rate ◽  
Airflow Field ◽  
Ventilation Performance ◽  
Dynamics Simulations

This study employed two ventilation indexes: local mean age of air and air change rate per hour, to investigate wind-induced natural ventilation of 260 wards of a multi-storey hospital building in suburb of Guangzhou using computational fluid dynamics simulations. Using the surface-grid extrusion technique, high-quality hexahedral grid cells were generated for the coupled outdoor and indoor airflow field. Turbulence was solved by the renormalisation group k-ɛ model validated against experimental data with grid independence studies. Homogeneous tracer gas emission was adopted to predict room age of air. The air change rate of cross ventilation and single-sided ventilation can reach 30–160 h−1 and 0.5–7 h−1, respectively. Due to different locations of room openings on the balconies, natural ventilation of a room can be greatly better than its neighbouring room. The wind-induced cross ventilation highly depends on the distance from the room opening to the stagnation point and on the resulting pressure distribution on the target building surface. Furthermore, it is significantly influenced by the upstream buildings, the bent shape of the target building, and the prevailing wind directions. The coupled computational fluid dynamics methodologies with integrated ventilation indexes are useful for assessing the natural ventilation performance in other complex built environments.

scholarly journals Cross-Sectional Study on Prevalence of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) Specific RNA and Anti-MERS-RBD in Camel Milk from Different Regions of Saudi Arabia

2021 ◽  
Author(s):  
Aiydh Alshehri ◽  
Mir Naiman Ali ◽  
Nabil Miled
Keyword(s):  
Saudi Arabia ◽  
Middle East ◽  
Close Contact ◽  
Cross Sectional Study ◽  
Middle East Respiratory Syndrome ◽  
Viral Rna ◽  
Camel Milk ◽  
Cross Sectional ◽  
Milk Samples ◽  
Drinking Milk

Abstract Background: Middle East respiratory syndrome coronavirus (MERS-CoV) causes viral pneumonia disease in humans. The close contact with camels and drinking milk may cause Middle East respiratory syndrome coronavirus transfer to humans. Methods: This study was designed to detect the existence of Middle East respiratory syndrome coronavirus in camel milk samples collected from healthy animals according to local customs from 83 barns located around Saudi Arabia. Camel milk samples were examined for viral RNA by RT-qPCR, also ELISA assay was performed to detect IgG antibodies directed against MERS Receptor-Binding Protein (RBD).Results: Among 83 camel milk samples tested,the result showed that seven samples (8.4%) were positive for MERS-CoV RNA, while 40.9% of camel milk samples had antibodies directed against this virus.Conclusions: The findings indicate that some regions (East and South part) are characterized by a high incidence of viral antibodies. The South western region displayed the lowest infection rates. Camel breed Sahilia seems to be resistant to viral infection as compared to other breeds such as Hamra. This need to be more explored in order to reduce spread of infection and also to understand the underlying reasons. The presence of viral RNA in camel milk samples warrants for measures to prevent possible food-borne transmission of Middle East respiratory syndrome coronavirus through milk consumption.

scholarly journals A Discussion Regarding the Measurement of Ventilation Rates Using Tracer Gas and Decay Technique

2020 ◽  
Vol 5 (10) ◽  
pp. 85
Author(s):  
Ricardo M. S. F. Almeida ◽  
Eva Barreira ◽  
Pedro Moreira
Keyword(s):  
Cross Contamination ◽  
Single Family ◽  
Outdoor Temperature ◽  
Time Dependency ◽  
Tracer Gas ◽  
Large Variability ◽  
Change Rate ◽  
Air Change Rate ◽  
Ventilation Rates

The measurement of ventilation rates is crucial in understanding buildings’ performances, but can be a rather complex task due to the time-dependency of wind and buoyancy forces, which are responsible for the pressure differences that induce air movement across the envelope. Thus, assessing air change rate through one-time measurements during brief periods of time may not be a reliable indicator. In this paper, the variability in the measurement of ventilation rates using the decay technique was evaluated. To that end, two compartments of a typical single-family detached dwelling were selected as a case study and 132 tests were performed, considering two different boundary conditions (door closed and door open). This work allowed the large variability of the results to be highlighted, as the coefficient of variation ranged from 20% to 64%. Wind speed had a key effect on the results, especially because during the measurements indoor–outdoor temperature differences were not so significant. The possibility of using occupant-generated carbon dioxide as tracer gas was also analyzed, but problems of cross-contamination were identified.

Stable carbon isotope labelled carbon dioxide as tracer gas for air change rate measurement in a ventilated single zone

2017 ◽  
Vol 115 ◽  
pp. 173-181 ◽  
Author(s):  
K.E. Anders Ohlsson ◽  
Bin Yang ◽  
Alf Ekblad ◽  
Christoffer Boman ◽  
Robin Nyström ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Isotope ◽  
Stable Carbon Isotope ◽  
Rate Measurement ◽  
Stable Carbon ◽  
Tracer Gas ◽  
Change Rate ◽  
Air Change Rate

scholarly journals SARS-CoV-2 analysis on environmental surfaces collected in an intensive care unit. Keeping Ernest Shackleton´s spirit.

2020 ◽  
Author(s):  
Dolores Escudero ◽  
Jose Antonio Boga ◽  
Javier Fernández ◽  
Lorena Forcelledo ◽  
Salvador Balboa ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Environmental Contamination ◽  
Negative Pressure ◽  
Close Contact ◽  
Change Rate ◽  
Environmental Surfaces ◽  
Air Change Rate ◽  
Microbiological Control ◽  
Invasive Techniques

Abstract Background Intensive care unit workers are at high risk of acquiring COVID-19 infection, specially when performing invasive techniques and certain procedures that generate aerosols (<5 µm). Therefore, one of the objectives of the health systems should be to implement safety practices to minimize the risk of contagion among these health professionals. Monitoring environmental contamination of SARS-CoV-2 may help to determine the potential of the environment as a transmission medium in an area highly exposed to SARS-CoV-2, such as an intensive care unit. The objective of the study was to analyze the environmental contamination by SARS-CoV-2 on surfaces collected in an intensive care unit, which is dedicated exclusively to the care of patients with COVID-19 and equipped with negative pressure of -10 pascals and an air change rate of 20 cycles per hour. Results A total of 102 samples (72 collected with pre-moistened swabs used for collection of nasopharyngeal exudates and 30 with moistened wipes used in the environmental microbiological control of the food industry) were obtained from ventilators, monitors, perfusion pumps, bed rails, lab benches, containers of personal protective equipment, computer keyboards and mice, telephones, workers' shoes, floor and other areas of close contact with COVID-19 patients and healthcare professionals who cared for them. The analysis by quantitative RT-PCR showed no detection of SARS-CoV-2 genome in environmental samples collected by any of the two methods described.Conclusions Presence of SARS-CoV-2 on the ICU surfaces could not be determined supporting that personal protection, decontamination procedures and negative pressure settings are effective in preventing environmental contamination and protecting the staff and patients inside intensive care units.

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