Optimization Output for Exp. 275 | QMRA wiki

Basic information

Experiment ID	275
Agent Strain	Aa strain
Contains Preferred Model	No
Reference	John, D. T., & Hoppe, K. L. (1990). Susceptibility of Wild Mammals to Infection with Naegleria fowleri. The Journal of Parasitology, 76, 6.
Exposure Route	oral
Response	death

Detailed information

Host type	mice
# of Doses	5.00
Dose Units	CFU
Μodel	exponential
k	1.33E-07
LD50/ID50	5.22E+06

Description

**Mice/ Aa strain model data**
Dose	Dead	Survived	Total
1E+04	0	22	22
1E+05	1	21	22
1E+06	1	10	11
1E+07	16	6	22
1E+08	22	0	22

**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	1.27	0.0341	4	3.84 0.854	9.49 0.867
Beta Poisson	1.23	0.0341	3	3.84 0.854	7.81 0.745
Exponential is preferred to beta-Poisson; cannot reject good fit for exponential.

**Optimized k parameter for the exponential model, from 10000 bootstrap iterations**
Parameter	MLE estimate	Percentiles
Parameter	MLE estimate	0.5%	2.5%	5%	95%	97.5%	99.5%
k	1.33E-07	6.86E-08	7.91E-08	8.83E-08	2.06E-07	2.24E-07	2.75E-07
ID50/LD50/ETC*	5.22E+06	2.52E+06	3.10E+06	3.37E+06	7.85E+06	8.76E+06	1.01E+07
*Not a parameter of the exponential model; however, it facilitates comparison with other models.

Parameter histogram for exponential model (uncertainty of the parameter)

Exponential model plot, with confidence bounds around optimized model

References

Quan, S. F., McManus, A. G., & von Fintel, H. . (1956). Infectivity of Tularemia Applied to Intact Skin and Ingested in Drinking Water. Science, 123, 942-943.