Optimization Output for Exp. 42 | QMRA wiki

Basic information

Experiment ID	42
Pathogen	Escherichia coli
Agent Strain	ETEC O55 (in paper as “type 55, B5”)
Contains Preferred Model	No
Reference	June, R. ., Ferguson, W. ., & Worfel, M. . (1953). Experiments in feeding adult volunteers with Escherichia coli 55, B5, a coliform organism associated with infant diarrhea. American Journal of Hygiene, 57(2). https://doi.org/10.1093/oxfordjournals.aje.a119570
Exposure Route	oral
Response	slight to severe illness

Detailed information

Host type

human

# of Doses

4.00

Dose Units

CFU

Μodel

beta-Poisson

a

8.7E-02

N50

2.05E+05

LD50/ID50

2.05E+05

Experiment Dataset

Description

**Escherichia coli** **(ETEC O55 (in paper as “type 55, B5”)) in the human model data**
Dose	Slight to severe illness	No slight to severe illness	Total
1.43E+08	6	2	8
1.73E+09	5	2	7
5.33E+09	6	2	8
1.6E+10	7	1	8

**Goodness of fit and model selection**
Model	Deviance	Δ	Degrees of freedom	χ²_0.95,1 p-value	χ²_0.95,m-k p-value
Exponential	35	34.5	3	3.84 4.2e-09	7.81 1.21e-07
Beta Poisson	0.486	34.5	2	3.84 4.2e-09	5.99 0.784
Beta-Poisson fits better than exponential; cannot reject good fit for beta-Poisson.

**Optimized parameters for the beta-Poisson model, from 10000 bootstrap iterations**
Parameter	MLE estimate	Percentiles
Parameter	MLE estimate	0.5%	2.5%	5%	95%	97.5%	99.5%
α	8.7E-02	9.87E-04	1.02E-03	1.67E-02	3.57E-01	4.67E-01	7.83E-01
N₅₀	2.05E+05	3.40E-09	4.31E-06	2.31E-04	1.30E+08	2.09E+08	5.13E+08

Parameter scatter plot for beta Poisson model ellipses signify the 0.9, 0.95 and 0.99 confidence of the parameters.

beta Poisson model plot, with confidence bounds around optimized model

References

June, R. ., Ferguson, W. ., & Worfel, M. . (1953). Experiments in feeding adult volunteers with Escherichia coli 55, B5, a coliform organism associated with infant diarrhea. American Journal of Hygiene, 57(2). https://doi.org/10.1093/oxfordjournals.aje.a119570