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Experiment ID
253
Pathogen
Naegleria fowleri
Agent Strain
LEE 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
intravenous
Response
death
Host type
mice
# of Doses
3.00
Dose Units
no of trophozoites
Μodel
exponential
k
4.21E-07
LD50/ID50
1.64E+06
Description
mice/Naegleria fowleri LEE strain data 
Dose Dead Survived Total
2.5E+06 4 6 10
5E+06 19 1 20
1E+07 10 0 10

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value 		χ20.95,m-k 
p-value
Exponential 4.11 -9.67 2 3.84 
1 		5.99 
0.128
Beta Poisson 13.8 1 3.84 
0.000206
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
0.5% 2.5% 5% 95% 97.5% 99.5%
k 4.21E-07 2.77E-07 3.04E-07 3.25E-07 5.95E-07 6.79E-07 8.02E-07
ID50/LD50/ETC* 1.64E+06 8.65E+05 1.02E+06 1.16E+06 2.13E+06 2.28E+06 2.50E+06
*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

  • Adams, A. C., John, D. T., & Bradley, S. G. (1976). Modification of resistance of mice to Naegleria fowleri infections. Infection and Immunity, 13, 1387–1391. Retrieved from http://iai.asm.org/content/13/5/1387.full.pdf+html