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Vomiting Larry goes viral in the name of science

posted 11 Jan 2013, 07:22 by Mpelembe   [ updated 11 Jan 2013, 07:22 ]

A robot that vomits on demand is the latest weapon in Britain's war on norovirus, a disease currently affecting more than a million people throughout the country. Called "Vomiting Larry" by its developer, the humanoid simulated vomiting system is designed to help scientists analyse contagion by simulating the retching process at the same speed and range as a human.

BUXTON, ENGLAND, UNITED KINGDOM (JANUARY 10, 2013) (REUTERS) -  A British researcher has developed a humanoid vomiting system designed to help scientists analyse contagion.

Catherine Makison-Booth (PRON: May-kiss-an Booth) developed the humanoid simulated vomiting system at the Health and Safety Laboratory (HSL) in Derbyshire,northern England, nicknaming him 'Vomiting Larry'. Analysing his reach she's found that small droplets of vomit - and the germs they carry - can spread further than three metres.

Larry's projections are easy to spot because his mechanical stomach is primed with a 'vomitus substitute', which includes a fluorescent marker. After Larry's 'vomit' has been cleaned up and the lights are switched off, ultraviolet light usually shows small splashes that wouldn't be easily visible under standard white hospital lighting.

Makison-Booth came up with the idea for Larry during the UK's norovirus outbreak of 2010. Also known as the winter vomiting bug, norovirus can cause projectile vomiting, diarrhoea, nausea, and loss of taste. It's transmitted directly between people via aerosolisation, with particles floating through the air, and indirectly by contaminated consumables like food and water. The bug has been described as 'the Ferrari of the virus world' and is one of the most infectious viruses known to man, causing 21 million illnesses annually in the US alone.

Makison-Booth created Larry by adapting a mannequin head typically used by medical students. She explained: "Larry is comprised of a mannequin head, which is known as 'Airway Larry', and he's what medical students use to practise things like laryngoscopies on the incubation, so he's very realistic. He has a real tongue and teeth in there that are different material types. His oesophagus is then linked to a cylinder which contains the fluid, so that's essentially his stomach. A piston or push-rod then pushes the fluid up via a pneumatic ram which forces air under the piston, pushes the fluid up and out of Larry's mouth."

Making Vomiting Larry anatomically correct was difficult, requiring Makison-Booth to delve through old textbooks because, she says, previous research on vomiting was limited. Having made a series of calculation she constructed the model.

"The amount of pressure then was based on the amount of fluid that we had in the stomach and the distance that it would travel for the main bulk of fluid to land on the floor, i.e. 1.2 metres, and that then took 800 kilopascals in order to exert that pressure through the system and enter onto the floor," Makison-Booth explained.

The vomit usually consists of water and a fluorescent marker, so scientists can see how far the fluid spreads, but they have sometimes included a mind-boggling number of viruses into the mix.

"We've added a thousand million viruses to one litre, which is the amount of fluid that we generally use, and then allow him to vomit out the virus to see whether the virus survives the vomiting process and also whether it survives the distance of spread that we've noted just with using the fluid, just with using the water and the fluorescent dye," said Makison-Booth.

The researcher, who conducted most of the research at the HSL alone, made some unexpected discoveries.

"We've noticed that first of all the vomit travels a lot further than we anticipated, in excess of three metres as I've said. and also you can't see where just exactly the extent of spread (is) either and therefore it's difficult to clean up, particularly if someone was vomiting say on a carpet where the vomit would be absorbed to some extent within that material."

Among the infected each individual splattering of vomit contains enough noroviruses to infect many people because it only takes around 20 particles to fully infect someone.

By the end of December more than a million Britons were believed to have suffered the bug this winter. The Health Protection Agency (HPA) said this high rate of infection relatively early in the winter mirrors trends seen in Japan and Europe.

Norovirus dates back more than 40 years and takes its name from the U.S. city of Norwalk, Ohio, where there was an outbreak of acute gastroenteritis in school children in 1968. Symptoms include a sudden onset of vomiting, often projectile, and diarrhoea, which may be profuse and watery. Some victims also suffer fevers, headaches and stomach cramps.

What makes this such a formidable enemy is its ability to evade death from cleaning and to survive long periods outside a human host. Scientists have found norovirus can remain alive and well for 12 hours on hard surfaces and up to 12 days on contaminatedfabrics such as carpets and upholstery. In still water, it can survive for months, maybe even years.

Makison-Booth believes Larry will prove an invaluable tool for medical students and could also be used to train cleaners on cruise ships and oil rigs, enclosed locations where outbreaks can be particularly severe.