Investigating effects of between- and within-host variability on Escherichia coil 0157 shedding pattern and transmission
Authored by S. Chen, M. Sanderson, C. Lanzas
Date Published: 2013-04-01
DOI: 10.1016/j.prevetmed.2012.09.012
Sponsors:
United States National Institute for Mathematical and Biological Synthesis (NIMBioS)
University of Tennessee
United States Department of Agriculture (USDA)
United States Department of Homeland Security
United States National Science Foundation (NSF)
Platforms:
R
Model Documentation:
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Abstract
Healthy cattle and their environment are the reservoir for the human pathogen Escherichiacoli O157. In E. coli O157 epidemiology, supershedders have been loosely defined as cattle that shed high concentrations of E. coli O157 (>= 10(4) colony-forming cells (CFU)/g of feces) at a single (or multiple) cross-section in time. Due to the variability in the pathogen shedding level among animals (between-host variability), as well as fluctuations in the level shed by a single animal (within-host variability), it is difficult to interpret fecal bacteria distributions, as well as to parse the relative contribution of between- and within-host variability to the observed shedding patterns at the pen level. We developed an agent-based model that integrates individual animal data on temporal fecal shedding dynamics with pen-level E. coli O157 transmission to study how the temporal (and aggregation) patterns of E. coil O157 shedding loads and prevalence arise at the pen level. We demonstrated that even without between-host variability, the prevalence of animals with concentration of E. coil O157 in feces that exceeds 10(4) CFU/g is similar to that observed in cross-sectional field data. Both within-host and between-host variability can generate supershedders. (C) 2012 Elsevier B.V. All rights reserved.
Tags
Mathematical model
Between- and within-host variability
Escherichia coli 0157
Fecal shedding
Supershedder