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Why these scientists built a vomiting machine

Scientists at North Carolina State University have invented a “vomiting machine” that looks at why the stomach-turning norovirus spreads so far and so fast.

The researchers recently published a study in PLOS One about how viruses are spread when an infected individual throws up. They were specifically interested in human noroviruses (NoV), of which there are 21 million cases each year in the U.S. alone, according to the study’s introduction.

It has long been believed that vomiting causes a virus to become airborne. These researchers set out to prove that notion and discover to what extent, so they built a “simulated vomiting device…at one-quarter scale of the human body.”

They combined imitation saliva and vomit (vanilla pudding) with MS2, a virus that’s harmless to humans. This mixture was placed inside the machine’s “stomach” and expelled in a fashion that imitates a natural vomiting episode. The solution was collected in a chamber and the air was essentially vacuumed out to measure the amount of airborne bacteria.

They tested concentrations of the aerosolized MS2 virus with different amounts of “vomit.” The lowest percentage of aerosolized virus they measured contained 36 virus particles; the highest percentage contained upwards of 13,000. NoV is extremely infectious and someone only needs to be exposed to 20-1,300 particles in order to be infected.