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Case Study

Vomiting Larry: Visualising Contamination

The Client

Department of Health, Health and Safety Executive

The Problem

In order to help reduce the numbers of Norovirus outbreaks and therefore improve public/workforce health and reduce the burden on our economy, HSL developed a simulated vomiting system known as vomiting Larry.

Norovirus (a winter vomiting disease) causes large outbreaks of gastroenteritis worldwide. Outbreaks are most common in winter with key symptoms of projectile (forced) vomiting and/or diarrhoea. It is highly infectious and robust being resistant to many disinfectants including the frequently used alcohol hand rubs. Many industry sectors are affected by norovirus outbreaks, which impacts substantially on our economy with a burden on the NHS alone of around £100m per annum.

What We Did

This project was carried out by HSL's microbiology, virology and workplace sampling team with help from other teams across the Laboratory including exposure and control, immunology and toxicology, Centre for Workplace Health, fluid dynamics, epidemiology, visual presentation services and workshops. In order to help reduce the burden of norovirus on our health and the economy, HSL specialists:

  • Developed a simulated vomiting system known as Vomiting Larry to identify how much of the environment becomes contaminated when an individual infected with Norovirus projectile vomits;
  • Employed a commercially available realistic mannequin head known as Airway Larry normally used as a training system for medical students on which to practice procedures such as laryngoscopies;
  • Utilised a pneumatic ram and cylinder to form a piston pump system allowing fluid to be forced out of the realistic mannequin head;
  • Used one of HSL's controlled atmosphere chambers (35 m3 facility) in which to conduct the vomiting trials;
  • Initially used water containing a fluorescent tracer as a vomit substitute enabling researchers to identify how far small droplets travelled using UV light, which would otherwise be invisible;
  • Simulated projectile vomiting trials were also carried out using a non-hazardous form of norovirus to identify how far and how much live virus could be spread in the environment.

Other Findings:

  • HSL found that in an episode of projectile vomiting 1 litre of fluid could contaminate an area >7.8 m2
  • Live virus could be found even in very small droplets of fluid in numbers capable of causing infection
  • The research identified the need for wider area cleaning and decontamination of the environment during episodes of vomiting/norovirus outbreaks
  • The results of the study emphasised the need for wider area cleaning and decontamination of the environment and were sent to a norovirus working group who were preparing some new guidance on norovirus


The research findings will now form part of a doctoral research degree being undertaken by an HSL staff member, and has the following benefits:

  • Better opportunity to prevent Norovirus in future, through improved knowledge of need for wider cleaning and decontamination
  • Raised profile of Norovirus through numerous media opportunities - Vomiting Larry has received a large amount of media interest including a part in a BBC documentary: 'Winter viruses and how to beat them' presented by Michael Mosley (February 2013) and short documentaries for Thomson Reuters and the Discovery Channel.

 See Vomiting Larry

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