Scientists at North Carolina State University have invented a vomiting robot in order to learn how the norovirus spreads. Norovirus is highly contagious and the U.S. sees around 21 million cases a year.
The challenge has been in examining the different ways someone could transmit the norovirus to another individual. An impressive amount of the virus is shed through fecal matter—millions to billions of virus particles per gram—but this is not an effective avenue of exposure in a nation like the U.S.
For the past 20 years, there was suspicion that norovirus particles could be aerosolized in vomit, but there has been no effective means of confirming this. Getting infected patients or volunteers to throw up on command in a laboratory setting has numerous practical and ethical issues; hence, the vomiting robot.
The machine itself is a scaled-down version of a human’s stomach system that is capable of spewing at a rate, volume, and velocity in line with the real action. The vomit itself is simulated using various mixtures of JELL-O pudding, artificial saliva, and green food coloring. For safety reasons, the actual norovirus cannot be employed, so a bacteriophage called MS2, which can’t hurt humans, is used instead. The robot vomits into an enclosed box and an attached biosampler collects air particles, which the scientists examine to determine how much of the virus is present.
On average, it was found that about 13,000 particles—roughly 0.02% of the virus shed in the vomit itself—was aerosolized. While a seemingly small amount, especially when compared to the levels shed in fecal matter, it takes as few as 20 virus particles to create a reasonable chance of infection.
Having verifiable evidence that norovirus is aerosolized in vomit is an important step forward in prevention techniques. It allows scientists and health officials to enact and plan procedures without relying on uncertain hypotheticals, permitting more precise and effective developments.
Sources for Today’s Article:
Oaklander, M., “This Machine Vomits On Command For Science,” TIME web site, August 19, 2015; http://time.com/4003121/vomiting-machine-norovirus/.
Tung-Thompson, G., et al., “Aerosolization of a Human Norovirus Surrogate, Bacteriophage MS2, during Simulated Vomiting,” PLOS ONE 2015, 10(8): e0134277, doi: 10.1371/journal.pone.0134277.