In a poorly ventilated environment, MERS virus can be spread through the air (news report)

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Did poor ventilation lead to MERS 'superspread' in Korea?

By Kai Kupferschmidt 5 June 2015 5:00 pm

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The room in which patient zero stayed was originally meant for six people (the standard in Korea), but it had recently been divided, Lee says. It had only one small window that remained closed during the day, and there was no ventilation. An air conditioning unit cycled the air in the room, Lee told ScienceInsider. ?The air conditioner is working in this small room with the door closed, so we are speculating that there is a very high density of virus particles in the air.? He also says that virus RNA was detected on the membrane of the room?s air conditioning unit.

None of the scientists leading the investigation could be reached for comment, and a spokesperson at KCDC acknowledged only that a ?team consisting of experts in various fields is investigating the ventilation system of [that] hospital.? Peter Ben Embarek, the point person on MERS at the World Health Organization (WHO), says that he has also been informed about a lack of ventilation in the room. ?It?s very difficult to draw any conclusions based on what little information we have. We will hopefully get a more detailed picture soon of that part of the investigation.?

Bad ventilation alone would hardly explain the catastrophic spread seen in the hospital, says Christian Drosten, a virologist at the University of Bonn in Germany. But if there was bad ventilation plus a patient shedding a greater than usual amount of the virus, it could make a difference...

?A highly infectious case, combined with poor infection control can easily lead to this kind of cluster,? says Mike Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, Twin Cities.
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http://news.sciencemag.org/asiapacific/2015/06/did-poor-ventilation-lead-mers-superspread-korea

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Translation Google

MERS Korea's first patient to ward virus through airborne survey

At 11:10 on June 11, 2015 Source: China News Network

BEIJING, June 11, according to Korean media reports, recently, (MERS) process in the Middle East respiratory syndrome virus from spreading be explained by scientific way. June 7, epidemiological investigation committee coordinated tribune MERS Korea Headquarters for affiliated St. Mary's Hospital to find out Pyeongtaek transmission of the virus, the first case of MERS infection in check No. 8104 Ward simulated evidence, and draw conclusions.

According to reports, on June 10, according to the Committee to participate in the epidemiological investigation of empirical said the officer, "is confirmed, the patient coughs or sneezes, the virus will be full discharge is not equipped with vents, vent the entire ward, If the ward windows and doors suddenly opened, the virus will spread along the corridor outside the ward and other wards. " This means that, in a poorly ventilated environment, MERS virus can be spread through the air. The first case of a patient in a hospital after a total of 36 people have been two or three infections.

According to reports, the Commission in ward No. 8104 produced the particle sizes of the water fills the room, and observing the extent that they diffuse in different conditions. By air under high pressure and special medicines with effect obtained with the patient cough droplets spilled like water particles.

The Committee also simulated the windows and doors opening and closing, and other circumstances that may arise in the ward. The results showed that the particles floating in the air in the moment the door opened gush ward. Headquarters for the person in charge said, "After we conclude that open windows and doors, MERS virus can spread to every corner of the eighth floor of the hospital."

According to South Korean health authorities explained that only close contact with the virus within two meters, will be infected with MERS. The reason is that MERS virus spread by droplets from the mouth of the patient, and after splashing droplets from the patient's mouth, generally no more than two meters will fall.

However, a major outbreak in Pyeongtaek MERS St. Mary's Hospital, but could not be explained by the above principles. Among 26 patients with secondary infection is the first case of MERS, 22 per capita for the patient to other wards. In the first epidemiological survey, hidden on three air conditioning filter of MERS virus is detected, and then there is speculation that "the virus may spread along with the air-conditioning duct." However, when the first case of hospitalization (May 15 to 17), air conditioning has not been enabled. The committee was to unlock the empirical "Hirasawa St. Mary's Hospital Puzzle" provides strong evidence.

It was confirmed that when patients cough droplets splashing split into smaller molecules, which float in the air. According to another interpretation of the Headquarters for the person concerned, "Empirical evidence shows that larger droplets will spill outside the ward. With the increase in the number of droplets, which gradually split into suspended particulate (aerosol ? fine water particles) and floating in the air. " Smaller suspended particles, can stay in the air, but smaller than the virus, it can be attached to the suspended particles move.

As we all know, in the course of medical treatment in the hospitals, the virus can spread themselves by suspended particles. Medical College of Preventive Medicine, Dongguk University classroom States Li Guan (sound) professor said, "during the course of hospital medical services, since the suction, oxygen respirator, the virus will appear in the form of suspended particles," "time Virus produced the most first patient, if the virus compared to smoke, then was certain foggy "in the patient ward. In addition, the results also show that even after the fall of the droplets dry ground, in the windows and doors open still wind.

The survey also shows that there is no vent in the ward number 8104 and an exhaust port, its room structure itself is very easy to spread of the virus. The ward area of 50.4 square meters, and later split into two two world ward, this way, Ward No. 8104, there is no vent.

It reported that the first patient lived in the ward air filled with MERS virus, which is caused by the structural changes in the ward. Hanyang University, Yang Yun inside (sound) professor said, "The hospital has 32 inpatient wards, but no vents, vent happens within the first case of MERS patient ward."

In addition, it was pointed out that not because the virus can be spread through the air to conclude that this will lead to infection. Professor of Medicine, Korea University Kim Cheng group (sound) said, "the number of virus particles suspended due to small size, can carry very limited. Even viruses get spread, also requires a certain amount will be raised after infection. Depending on the disease and has the ability to spread the number of virus is also different. " Jin Cheng group also added that "the emergency room from Samsung Seoul Hospital a large area of infection, and later within the AMC Security in contact with the patient 10 min are infected can be seen that the ability to communicate MERS stronger than we thought."
[Edit: He Lu Man]

http://www.chinanews.com/gj/2015/06-11/7337362.shtml