P2-97 Modeling Norovirus Transmission from an Episode of Vomiting

Tuesday, July 30, 2013
Exhibit Hall (Charlotte Convention Center)
Grace Tung, North Carolina State University, Raleigh, NC
Dominic Libera, North Carolina State University, Raleigh, NC
Francis de los Reyes, North Carolina State University, Raleigh, NC
Lee-Ann Jaykus, North Carolina State University, Raleigh, NC
Introduction: The importance of vomiting incidents in the transmission of human noroviruses (NoV) is increasingly recognized and there are examples of food becoming contaminated because of such events.  Effective cleaning and sanitation after vomiting in public places like food service establishments remains challenging.  Unfortunately, little is known about the role of vomiting on NoV transmission.

Purpose: As part of a broad project to model the impact of vomiting on foodborne NoV transmission, the purpose of this work was to characterize the radius of impact of a simulated vomiting event.

Methods: To model vomit “splatter,” or the distance traveled by vomitus upon its deposition on a solid surface, a “Tipping Bucket” experiment was designed.  This consisted of rigging a bucket to a ladder, and pouring colored simulated vomitus onto a tarp upon which a target was drawn, allowing the measurement of the distance from the center of splatter to the farthest droplet. Data were also recorded by camera.  Two simulated vomitus matrices were used:  reconstituted instant oatmeal (to simulate vomitus having high solids content) and artificial saliva (a dilute solution porcine mucin in saline).  Volumes ranging from 50-800 ml were dropped 3.5 ft. off the ladder.  The ImageJ program was used to analyze the data. 

Results: For oatmeal, the furthest distance traveled by a droplet was highly dependent upon volume, with the mean distance traveled ranging from 3-3.5 ft. for higher volumes (> 600 ml).  On the other hand, regardless of volume, artificial saliva experiments yielded a mean distance of 8-12 ft.; the greatest distance traveled in any one experiment was 14.5 ft. 

Significance: Taken together, these measurements suggest that vomitus splatter can be deposited between 3 and 15 ft. away from the initial vomiting contact area.  This has implications relative to recommended clean up zones after a public vomiting event.  Further work to characterize aerosolization of vomitus is in progress.