Optimization Output for Exp. 81 | QMRA wiki

Basic information

Experiment ID	81
Pathogen	Shigella dysenteriae
Agent Strain	M 131
Contains Preferred Model	No
Reference	DuPont, H. L., Hornick, R. B., Dawkins, A. T., Snyder, M. J., & Formal, S. B. (1969). The Response of Man to Virulent Shigella flexneri 2a. Journal of Infectious Diseases, 119, 3.
Exposure Route	oral (in milk)
Response	illness

Detailed information

Host type

human

# of Doses

4.00

Dose Units

CFU

Μodel

beta-Poisson

a

2.77E-01

N50

2.38E+02

LD50/ID50

2.38E+02

Experiment Dataset

Description

**Model data for** **Shigella dysenteriae** **(M 131) in the human**
Dose	Illness	Not illness	Total
10	1	9	10
200	2	2	4
2000	7	3	10
1E+04	5	1	6

**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	13.2	13.2	3	3.84 0.000283	7.81 0.0042
Beta Poisson	0.0315	13.2	2	3.84 0.000283	5.99 0.984
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	2.77E-01	5.24E-03	1.10E-01	1.34E-01	1.63E+00	1.88E+01	1.72E+03
N₅₀	2.38E+02	1.35E+01	4.73E+01	6.36E+01	1.42E+03	2.02E+03	5.89E+03

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