Modelling the vector pathway and infection of humans in an environmental outbreak of Escherichia coli O157.
Quantifying the transfer of Escherichia coli O157 from the environment to humans is essential for understanding outbreaks, establishing the infectious dose of the organism and proposing safeguards. We modelled the pathogen loading shed onto a field by sheep immediately prior to a scout camp where 18 scouts and two adults were infected with E. coli O157. We estimated the dose ingested (4-24 organisms) which is in agreement with the low infective dose reported previously for this organism in food outbreaks. These data closely fit a surrogate Shigella dose-response model which can be used as a basis for risk assessment.
Strachan
N J
NJ
Department of Plant and Soil Science, University of Aberdeen, Aberdeen AB24 3UU, U.K. n.strachan@abdn.ac.uk
Fenlon
D R
DR
Ogden
I D
ID
D000818:Animals; D004195:Disease Models, Animal; D004196:Disease Outbreaks; D004199:Disease Vectors; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D019453:Escherichia coli O157; D005243:Feces / Q000382:microbiology; D006801:Humans; D012756:Sheep / Q000382:microbiology*; D012988:Soil Microbiology; D006113:United Kingdom / Q000453:epidemiology