The British have long referred to Norovirus as “the vomiting disease,” but now a “vomiting machine” has been invented at North Carolina State University and put to serious use in the study of how the illness spreads. This week, the open source journal PLOS ONE published the NC State research under the title, “Aerosolization of a Human Norovirus Surrogate, Bacteriophage MS2, during Stimulated Vomiting.” NC State’s Dr. Ben Chapman, who writes for Barfblog, was quick to quip that the research publication means that the vomiting machine is no longer “not just for parties.” Apparently it may have a little history as it was built a couple years before being put into use for formal experiments. Chapman, an associate professor and food safety Extension specialist at NC State, reports that extensive testing was required to make sure the machine was scaled properly. The vomiting machine, according to university pitchman Matt Shipman, “looks like a glorified air compressor with a grotesque clay face.” He wrote that the vomiting machine “does exactly what you think it does.” Nobody associated with NC State is calling Norovirus a laughing matter. Shorthand for 30 related viruses, Norovirus makes about 21 million Americans sick each year, causing both vomiting and diarrhea. It can pose a deadly threat, especially to the elderly, and its rapid transmission, especially in confined settings, such as nursing homes, hospitals, hotels, and cruise ships, makes it difficult to get under control. The NC research team set out to show how “virus aerosolization occurs in a simulated vomiting event, and to estimate the amount of virus that is released in those aerosols.” To do that, they had to build a “laboratory physical model to simulate human vomiting” and then deploy the vomiting machine “under various conditions of volume and pressure.” Human NoV, as the researchers call it, is transmitted by various means, but “projectile vomiting” is right up there at the top of the list. “In fact, there have been many outbreaks occurring in hotels, schools, aircraft, concert halls, and cruise ships for which vomiting has been implicated as having a role in transmission,” NC researchers wrote. Funded by USDA’s National Institute of Food and Agriculture, the research team includes Grace Tung-Thompson, Lee-Ann Jaykus, Dominic A. Libera, Kenneth L. Koch, and Francis L de los Reyes III. To study the person-to-person spread of Human NoV, Tung-Thompson and Jaykus came to realize that they needed a way to aerosolize it and then study repeated vomiting events. “They needed a vomiting machine,” Chapman explains. “As you may imagine, there is a limited demand for vomiting machines, so the researchers had to design and build their own.” Then enlisted Libera, a construction and engineering graduate student, in Reyes’s engineering lab. And then they brought in Koch, the only NC team member who is a gastroenterologist at Wake Forest University, to generate the data. “Working together, the researchers created a machine that is essentially a scaled-down version of the mouth, esophagus, and stomach — made of tubes an a pressure chamber that passes through a clay face to give it the correct vomiting angle.” Perhaps the best part is “the vomitus containment chamber,” a most important part to contribute to any “simulated vomiting event.” The first-of-its-kind study came up with ranges for how much of the virus might be vomited in aerosolized form. It will likely bring better understanding to the “transmission dynamics” that could help with the design of effective control measures.
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