QMRA Introduction
The overall mortality rate for E. coli O157:H7 is <1%. For those who develop hemolytic uremic syndrome, the death rate is between 3-5% (www.azdhs.gov)
Hosts
Animals and humans
Transmission / Exposure Route
Fecal-oral route, and most illness has been associated with eating undercooked, contaminated ground beef, swimming in or drinking contaminated water, and eating contaminated vegetables; but direct person-to-person contact can also spread infection[1]
Case Fatality Ratio
| Case Fatality Ratio | Pathway/conditions | Population | References |
| 8% | Neonatal Meningitis | Not Reported | [2] |
| 3-5% | Developed hemolytic uremic syndrome | Not Reported | [1] |
| <1% | Not Reported | Overall | [1] |
Incubation Period
The incubation time for E. coli O157:H7 can be from 2 to 8 days, but it usually ranges from 3 to 4 days[1]
Burden of Disease
The incidence of E. coli O157:H7 and non-O157 infection per 100,000 population in 2008 is 1.12 and 0.45.[3]
Duration of infectiousness and disease
Symptomology
Severe stomach cramps, diarrhea, and vomiting are common symptoms of E. coli O157:H7 infections. Fever can occur but is usually less than 38.5˚C. Symptoms generally subside within 5-7 days, although more extreme cases do exist. [4]
Excretion Rates (see Exposure)
Immunity
Microbiology
Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms.[5]
Dose Response Models
Route: oral (in milk), Response: positive stool isolation
beta-Poisson
P(response)=1−[1+dose21a−1N50]−a
