I’ve been lucky to be close to some excellent projects, some of the stuff and knowledge created through these projects ends up mattering to food safety nerds – especially those who are making risk management decisions. Former NC State student Grace Tung-Thompson’s PhD project on vomit spray and norovirus is one of the most impactful. The work was carried out as part of the USDA NIFA-funded NoroCORE project led by my friend Lee-Ann Jaykus.
I’ve talked to lots of Environmental Health Specialists, retailers and food service food safety folks about what Grace and fellow graduate student Dominic Libera put together and many respond with a weird level of enthusiasm for the barf project.
Mainly because a real question they struggle with is how far will virus particles travel from an up-chuck event – knowing this, and then cleaning and sanitizing helps limit the scope of a potential outbreak. Grace’s work was published in PLOS ONE a while ago, we used it as a centerpiece for a Conference for Food Protection issue on vomit clean up in 2016 (which, maybe, could be included in the oft rumored 2017 Food Code) and the Daily Beast covered the work today.
A couple of years ago, PhD student Grace Tung Thompson demonstrated something incredibly gross: When a person vomits, little tiny bits of their throw-up end up airborne. You could ingest them just by breathing air in the same room. As if that weren’t disconcerting enough, if the person got sick from a virus, there could be enough viruses in the air to get you sick, too. Just try not to think about that the next time the person in the row behind you throws up on an airplane.
So how do you get rid of airborne viruses? “There is no known technology that will eliminate norovirus if it’s in the air,” Jaykus said, “and there really aren’t a lot of technologies—safe technologies—that even are likely to work.” Her research team recently experimented with misting antiviral compounds into spaces as an alternative to disinfecting surfaces individually, and it worked, but not completely. This technique, known as fogging, can only be used in spaces that can be cleared out and contained, like bathrooms, for example. “I think we need that technology, and that technology is really, really important, but how the heck we’re going to develop it? I’m at a loss for words.”
From an individual perspective, the best you can do is get yourself far away from a vomiting incident; Jaykus recommends at least 100 feet. If you were in the middle of a meal at a restaurant and someone at the next table threw up, you’d probably be wise to stop eating, and to wash yourself and your clothes when you are able.
From the perspective of a restaurant owner, the best course of action is to do a really, really good job of the cleanup. Commercial vomit and fecal matter cleanup kits are catching on with bigger companies in the foodservice industry, says Jaykus. They provide personal protection, including disposable coveralls and respirator masks, in addition to the material required to pick up and wipe down the mess.
I’ve been lucky to be close to some excellent projects, some of the stuff and knowledge created through these projects ends up mattering to food safety nerds – especially those who are making risk management decisions. NC State student Grace Tung-Thompson’s PhD project on vomit spray and norovirus is one of the most impactful. The work was carried out as part of the USDA NIFA-funded NoroCORE project led by my friend Lee-Ann Jaykus.
I’ve talked to lots of Environmental Health Specialists, retailers and food service food safety folks about what Grace and fellow graduate student Dominic Libera put together and many respond with a weird level of enthusiasm for the barf project.
Mainly because a real question they struggle with is how far will virus particles travel from an up-chuck event – knowing this, and then cleaning and sanitizing helps limit the scope of a potential outbreak. Today Grace’s work was published in PLOS ONE.
Matt Shipman, Research Communications Lead for University Communications and all around great guy writes about the project for The Abstract:
Tucked away in a quiet lab on NC State’s Raleigh campus is something that looks like a glorified air compressor with a grotesque clay face. It’s called “the vomiting machine” and it does exactly what you think it does. Researchers are using it to study one of the most widespread pathogens in the United States: norovirus.
Norovirus is a group of more than 30 related viruses that can cause vomiting and diarrhea. Norovirus affects about 20 million people each year in the U.S., with infections that can lead to hospitalization and occasionally to death, particularly in the elderly. About a quarter of the time, “noro” infection is obtained by consuming contaminated foods or water. However, it is most often spread between people in close contact with each other. The epidemic GII.4 strain predominates, but there are others.
But how, exactly, is noro transmitted from person to person?
“Epidemiological studies have suggested that norovirus can be ‘aerosolized’ through vomiting, meaning that small particles containing norovirus can become airborne when someone throws up,” says Grace Thompson, a recent Ph.D. graduate whose work at NC State focused on how norovirus spreads through vomiting and how long it is detectable in vomit. (Fun fact: noro can still be detected in dried vomit after six weeks.)
“According to outbreak reports, it appears that people can become infected with noro if they are directly or indirectly exposed to vomiting events,” Thompson explains. “If aerosolized particles land on a countertop, you could also touch the counter with your hand, then touch your hand to your mouth, leading to infection.”
But while norovirus aerosolization by vomiting has long been suspected, no one knew if it was actually occurring. This is the sort of question that Lee-Ann Jaykus’s lab lives for.
Jaykus is a professor of food science at NC State and scientific director of the U.S. Department of Agriculture-National Institute of Food and Agriculture Food Virology Collaborative, also known as NoroCORE (short for Norovirus Collaborative for Outreach, Research, and Education). They are, quite simply, norovirus experts.
To see if vomiting could really aerosolize norovirus, researchers in Jaykus’s lab (including Grace Thompson) needed a controlled way to observe and study vomiting over and over again. They needed a vomiting machine.
As you may imagine, there is a limited demand for vomiting machines, so the researchers had to design and build their own. They found a partner in Dominic Libera, a graduate student in NC State’s civil, construction and environmental engineering department in Francis de los Reyes’s lab. They also needed data upon which to build their model. Dr. Kenneth Koch, a gastroenterologist with Wake Forest University, provided that expertise.
Working together, the researchers created a machine that is essentially a scaled-down version of the mouth, esophagus, and stomach – made of tubes and a pressure chamber that passes through a clay face to give it the correct vomiting angle. The machine is designed (using engineering similitude principles) to let researchers control the pressure and volume of the vomit, in order to mimic a range of natural vomiting behaviors. The whole thing is enclosed in a sealed plexiglas box and placed under a biosafety hood. (A short video of the machine can be seen here.)
Instead of vomit, the researchers use liquid solutions of different viscosities or thicknesses as “artificial vomitus” to reflect different stages of digestion. And, since they cannot use real norovirus, they used a bacteriophage called MS2, which is a virus that infects E. coli but is harmless to humans. MS2 is easy to culture and is a common stand-in for noro.
Putting The Machine To Work
In 2012 and 2013, the team did extensive testing of the machine, to make sure that it was scaled appropriately and worked the way they wanted it to. And in 2014, Thompson began using the machine for formal experiments.
And what did they find? Well, virus was indeed aerosolized. Although the amount of MS2 aerosolized as a percent of total virus “vomited” was relatively low (less than 0.3 percent), vomit from infected people contains millions of particles. When the math is done, this means that the actual amount of virus particles aerosolized during a single vomiting event ranges from only a few into the thousands, perhaps more. (This work was recently published in PLOS ONE. More information on the findings is available here.)
“And that is enough to be problematic because it only takes a few, perhaps less than 20, to make a susceptible person ill” Jaykus says. “This machine may seem odd, but it’s helping us understand a disease that affects millions of people. This is work that can help us prevent or contain the spread of norovirus – and there’s nothing odd about that.”
The outbreak cluster index case was an 18-month-old girl puking all over her bed. And her mom. Case 2 was the mom, who spent 12 hours in and out of the bathroom a day later. Case 3 was the 18-month-old’s grandfather who was sharing a bathroom with the mom.
Our guest bathroom.
The grandfather, known to my kids as Pop-Pop, spent a next night in the bathroom and was still recovering when he set out on a 14 hour drive back to Canada.
I swear it wasn’t our cooking.
Through my amateur epidemiology I think my house is now contaminated with norovirus and it’s only a matter of time before it gets to me. Even though I’ve hit the toilet with a bunch of chlorine (I went with the 5,000ppm CDC recommends) it’s a waiting game.
Puke and diarrhea from an individual ill with norovirus is particularly problematic as each gram of, uh, matrix contains millions of virus particles that are ready to infect, replicate and be expunged out towards the next host. It’s a pretty awesome biological cycle. Most of what is known about spread of noro from vomit to comes from outbreak investigations. Proximity to the event is related to attack rates (closer to the puddle and spray = increased likelihood for illness). Toilets can also be a source of spread (with a flush comes aerosolization).
In what has become one of my favorite ideas, some folks in the UK are testing out a vomit-spewing machine to evaluate spread of virus particles.
At the Health and Safety Laboratory in Derbyshire, northern England, where researcher Catherine Makisondeveloped the humanoid simulated vomiting system and nicknamed him “Vomiting Larry”, scientists analyzing his reach found that small droplets of sick can spread over three meters.
“The dramatic nature of the vomiting episodes produces a lot of aerosolized vomit, much of which is invisible to the naked eye,” Goodfellow told Reuters.
Larry’s projections were easy to spot because he had been primed with a “vomitus substitute”, scientists explain, which included a fluorescent marker to help distinguish even small splashes – but they would not be at all easily visible under standard white hospital lighting.
It may seem like an idea hatched in a dorm room, but machines like this are important for the food and food service industry. Recommendations for cleaning and sanitizing after a puke event need to be built on the data that something like Vomiting Larry can provide – do I need to pay as much attention to the light switch or faucet as I did the toilet bowl, lid and handle? There isn’t a whole lot of evidence to dictate practices.
