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Experiment ID
48
Pathogen
Giardia duodenalis
Agent Strain
From infected humans
Contains Preferred Model
No
Reference
Erlandsen, S. L., Sherlock, L. A., Januschka, M. ., Schupp, D. G., Schaefer, F. W., Jakubowski, W. ., & Bemrick, W. J. (1988). Cross-species transmission of Giardia spp.: inoculation of beavers and muskrats with cysts of human, beaver, mouse, and muskrat origin. Applied and Environmental Microbiology, 54, 11. Retrieved from http://aem.asm.org/content/54/11/2777.abstract
Exposure Route
stomach tube
Response
infection
Host type
muskrat
# of Doses
5.00
Dose Units
Cysts
Μodel
exponential
k
3.68E-06
LD50/ID50
1.89E+05
Description
Dose response data 
Dose Infected Non-infected Total
30 0 8 8
300 0 7 7
3E+04 0 6 6
125000 2 1 3
5E+05 4 1 5

 

Goodness of fit and model selection
Model Deviance Δ Degrees 
of freedom		 χ20.95,1 
p-value 		χ20.95,m-k 
p-value
Exponential 2.49 0.0417 4 3.84 
0.838 		9.49 
0.646
Beta Poisson 2.45 3 7.81 
0.484
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 3.68E-06 1.13E-06 1.35E-06 1.88E-06 9.60E-06 9.60E-06 9.60E-06
ID50/LD50/ETC* 1.89E+05 7.22E+04 7.22E+04 7.22E+04 3.68E+05 5.14E+05 6.14E+05
*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

  • Erlandsen, S. L., Sherlock, L. A., Januschka, M. ., Schupp, D. G., Schaefer, F. W., Jakubowski, W. ., & Bemrick, W. J. (1988). Cross-species transmission of Giardia spp.: inoculation of beavers and muskrats with cysts of human, beaver, mouse, and muskrat origin. Applied and Environmental Microbiology, 54, 11. Retrieved from http://aem.asm.org/content/54/11/2777.abstract