The spread of airborne infections in institutional settings such as hospitals, waiting rooms, prisons and homeless shelters is an important public health problem. This is especially true in resource poor settings, where the prevalence of TB is highest, and where preventive measures such as negative-pressure isolation rooms are hardest to implement.
A study published today in the freely available journal PLoS Medicine and carried out by researchers from the Department of Infectious Diseases and Immunity and the Wellcome Trust Centre for Clinical Tropical Medicine, Imperial College London, is the first to investigate the role of natural ventilation by opening windows and doors for preventing the transmission of airborne infection. This simple and low-cost measure is recommended by the WHO for preventing TB transmission in healthcare settings, but until now there have been no studies to support these guidelines.
The researchers, led by Dr. Rod Escombe from Imperial College London, studied eight hospitals in Lima, Peru, and measured natural ventilation in 70 different rooms where infectious patients are likely to be found, including respiratory isolation rooms, TB wards, respiratory wards, general medical wards, outpatient consulting rooms, waiting rooms, and emergency departments. They compared these with 12 modern mechanically-ventilated, negative-pressure respiratory isolation rooms.
The study found that natural ventilation when windows and doors were opened was more than double that of mechanically-ventilated, negative-pressure rooms functioning at the high rates recommended by guidelines, and 18 times that of rooms with windows and doors closed. Even at the lowest wind speeds, natural ventilation exceeded mechanical ventilation.
"We were surprised by how effective simply opening windows and doors was at generating high rates of ventilation, which would theoretically reduce the risk of transmission," says Dr Escombe. "Using an airborne infection model to predict the effect of natural ventilation on TB transmission, we estimated that in mechanically-ventilated rooms, 39% of susceptible individuals would become infected following 24 hours of exposure to untreated TB patients. This compared with 33% in modern and 11% in pre-1950 naturally ventilated facilities with windows and doors open."
Facilities built more than 50 years ago, characterized by large windows and high ceilings, had greater ventilation than modern naturally ventilated rooms. Some of these older facilities had been built especially for TB patients, along the design principles of TB sanatoria when fresh air was part of the treatment for TB in the pre-antibiotic era.
"We concluded that opening windows and doors provides high rates of ventilation and may therefore provide the most effective protection against airborne infection in low resource settings," says Dr Escombe. "Old-fashioned clinical areas with high ceilings and large windows provided the greatest protection. Mechanically ventilated negative-pressure isolation rooms are very expensive to install and maintain, and are limited to certain high risk areas such as TB isolation rooms. In contrast, natural ventilation is a low-cost, low-tech intervention that can be applied in many different areas, including waiting rooms, out-patient clinics and emergency departments, where many infectious patients are found. Whilst not suited to cold climates, natural ventilation offers an important infection control measure in the tropics, where the greatest burden of TB is found."
Craig Brierley | EurekAlert!
A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg
Urbanization to convert 300,000 km2 of prime croplands
27.12.2016 | Mercator Research Institute on Global Commons and Climate Change (MCC) gGmbH
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Power and Electrical Engineering
16.01.2017 | Information Technology
16.01.2017 | Power and Electrical Engineering