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We generally recommend a single dose-response model, and we justify the decision in terms of specific criteria. This decision is somewhat subjective, since dose response datasets seldom meet all of these criteria. If all available models are unsatisfactory, we choose a single model to ‘recommend with reservations’. Our recommended model will seldom (if ever) be the best model for all applications. The user should carefully choose the model that is most appropriate for their particular problem. 

Criteria for Model Selection

We prefer dose-response models with the following criteria, in rough order of importance: 

  1. Statistically acceptable fit (fail to reject goodness of fit, p > 0.05)
  2. Human subjects, or animal models that mimic human pathophysiology well
  3. Infection as the response, rather than disease, symptoms, or death
  4. Exposure route similar/identical to the exposure route of natural infection
  5. Pathogen strain is similar to strains causing natural infection
  6. Pooled model using data from 2 or more experiments, provided the data sets are statistically similar (fail to reject that datasets are from the same distribution, p > 0.05)
  7. Low ID50/LD50 (to obtain a conservative risk estimate)
Agent Exposure Route Μodel Optimized parameters Host type Agent Strain Response # of Doses Dose Units Reference Links
Mycobacterium avium exponential
k = 6.93E-04
LD50/ID50 = 1000

deer sub sp. Paratuberculosis Bovine infection 3 CFU Nisbet, D. I., Gilmour N. J., & Brotherston J. G. (1962).  Quantitative studies of Mycobacterium johnei in tissues of sheep. III. Intestinal histopathology. Journal of comparative pathology. 72, 80. all experiments
Naegleria fowleri exponential
k = 3.42E-07
LD50/ID50 = 2.03E+06

mice LEE strain death 7 no of trophozoites 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. all experiments
Poliovirus exponential
k = 4.91E-01
LD50/ID50 = 1.41E+00

human type 1,attenuated alimentary infection 3 PD50 (mouse paralytic doses) Koprowski, H. (1956).  Immunization against Poliomyelitis with Living Attenuated Virus. The American Journal of Tropical Medicine and Hygiene. 5, 3. all experiments
Prion beta-Poisson a = 1.76E+00

LD50/ID50 = 1.04E+05
N50 = 1.04E+05
hamsters scrapie strain 263k death 5 LD50 i.c. Jacquemot, C., Cuche C., Dormont D., & Lazarini F. (2005).  High Incidence of Scrapie Induced by Repeated Injections of Subinfectious Prion Doses. Journal of Virology. 79(14),  all experiments
Pseudomonas aeruginosa injected in eyelids exponential
k = 1.05E-04
LD50/ID50 = 6.61E+03

Swiss webster mice (5day old) ATCC 19660 death 12 CFU Hazlett, L. D., Rosen D. D., & Berk R. S. (1978).  Age-Related Susceptibility to Pseudomonas aeruginosa Ocular Infections in Mice. Infection and Immunity. 20, 1. all experiments
recommended experiment
Pseudomonas aeruginosa injected in eyelids beta-Poisson a = 1.9E-01

LD50/ID50 = 1.85E+04
N50 = 1.85E+04
white rabbit corneal ulceration 10 CFU Lawin-Brüssel, C. A., Refojo M. F., Leong F. L., Hanninen L., & Kenyon K. R. (1993).  Effect of Pseudomonas aeruginosa concentration in experimental contact lens-related microbial keratitis. Cornea. 12, 1. all experiments
recommended experiment
Pseudomonas aeruginosa injected in eyelids exponential
k = 3.22*10^-7
LD50/ID50 = 2150065

death 67 CFU Ojielo, C. I., Cooke K., Mancuso P., Standiford T. J., Olkiewicz K. M., Clouthier S., et al. (2003).  Defective phagocytosis and clearance of Pseudomonas aeruginosa in the lung following bone marrow transplantation. The Journal of Immunology. 171, 4416–4424. all experiments
recommended experiment
Pseudomonas aeruginosa contact lens exponential
k = 3.22*10^-7
LD50/ID50 = 2150065

death 67 CFU Ojielo, C. I., Cooke K., Mancuso P., Standiford T. J., Olkiewicz K. M., Clouthier S., et al. (2003).  Defective phagocytosis and clearance of Pseudomonas aeruginosa in the lung following bone marrow transplantation. The Journal of Immunology. 171, 4416–4424. all experiments
recommended experiment
Pseudomonas aeruginosa contact lens exponential
k = 1.05E-04
LD50/ID50 = 6.61E+03

Swiss webster mice (5day old) ATCC 19660 death 12 CFU Hazlett, L. D., Rosen D. D., & Berk R. S. (1978).  Age-Related Susceptibility to Pseudomonas aeruginosa Ocular Infections in Mice. Infection and Immunity. 20, 1. all experiments
recommended experiment
Pseudomonas aeruginosa contact lens beta-Poisson a = 1.9E-01

LD50/ID50 = 1.85E+04
N50 = 1.85E+04
white rabbit corneal ulceration 10 CFU Lawin-Brüssel, C. A., Refojo M. F., Leong F. L., Hanninen L., & Kenyon K. R. (1993).  Effect of Pseudomonas aeruginosa concentration in experimental contact lens-related microbial keratitis. Cornea. 12, 1. all experiments
recommended experiment
Pseudomonas aeruginosa intratracheal exponential
k = 1.05E-04
LD50/ID50 = 6.61E+03

Swiss webster mice (5day old) ATCC 19660 death 12 CFU Hazlett, L. D., Rosen D. D., & Berk R. S. (1978).  Age-Related Susceptibility to Pseudomonas aeruginosa Ocular Infections in Mice. Infection and Immunity. 20, 1. all experiments
Pseudomonas aeruginosa intratracheal beta-Poisson a = 1.9E-01

LD50/ID50 = 1.85E+04
N50 = 1.85E+04
white rabbit corneal ulceration 10 CFU Lawin-Brüssel, C. A., Refojo M. F., Leong F. L., Hanninen L., & Kenyon K. R. (1993).  Effect of Pseudomonas aeruginosa concentration in experimental contact lens-related microbial keratitis. Cornea. 12, 1. all experiments
Pseudomonas aeruginosa intratracheal exponential
k = 3.22*10^-7
LD50/ID50 = 2150065

death 67 CFU Ojielo, C. I., Cooke K., Mancuso P., Standiford T. J., Olkiewicz K. M., Clouthier S., et al. (2003).  Defective phagocytosis and clearance of Pseudomonas aeruginosa in the lung following bone marrow transplantation. The Journal of Immunology. 171, 4416–4424. all experiments
Rhinovirus beta-Poisson a = 2.21E-01

LD50/ID50 = 1.81E+00
N50 = 1.81E+00
human type 39 infection 6 TCID50 Hendley, J. O., Edmondson W. P., & Gwaltney J. M. (1972).  Relation between Naturally Acquired Immunity and Infectivity of Two Rhinoviruses in Volunteers. Journal of Infectious Diseases. 125, 3. all experiments
Rickettsia rickettsi beta-Poisson a = 7.77E-01

LD50/ID50 = 2.13E+01
N50 = 2.13E+01
pooled R1 and Sheila Smith morbidity 27 CFU Saslaw, S., & Carlisle H. N. (1966).  Aerosol infection of monkeys with Rickettsia rickettsii. Bacteriological Reviews. 30, 3. all experiments
Rotavirus beta-Poisson a = 2.53E-02

LD50/ID50 = 6.17E+00
N50 = 6.17E+00
human 8 FFU Ward, R. L., Bernstein D. I., Young E. C., Sherwood J. R., Knowlton D. R., & Schiff G. M. (1986).  Human Rotavirus Studies in Volunteers: Determination of Infectious Dose and Serological Response to Infection. Journal of Infectious Diseases. 154, 5. all experiments
Salmonella anatum beta-Poisson a = 3.18E-01

LD50/ID50 = 3.71E+04
N50 = 3.71E+04
human strain I positive stool culture 16 CFU McCullough, NB., & Elsele CW. (1951).  Experimental human salmonellosis: I. Pathogenicity of strains of Salmonella meleagridis and Salmonella anatum obtained from spray-dried whole egg. Oxford Journal of Infectious Diseases. 88(3),  all experiments
Salmonella meleagridis beta-Poisson a = 3.89E-01

LD50/ID50 = 1.68E+04
N50 = 1.68E+04
human strain I infection 11 CFU McCullough, NB., & Elsele CW. (1951).  Experimental Human Salmonellosis: I. Pathogenicity of Strains of Salmonella Meleagridis and Salmonella Anatum Obtained from Spray-Dried Whole Egg. Oxford Journal of Infectious Diseases. 88(3),  all experiments
Salmonella newport exponential
k = 3.97E-06
LD50/ID50 = 1.74E+05

human *Salmonella newport* infection 3 CFU McCullough, NB., & Elsele CW. (1951).  Experimental Human Salmonellosis: I. Pathogenicity of Strains of Salmonella Meleagridis and Salmonella Anatum Obtained from Spray-Dried Whole Egg. Oxford Journal of Infectious Diseases. 88(3),  all experiments
Salmonella nontyphoid beta-Poisson a = 2.1E-01

LD50/ID50 = 4.98E+01
N50 = 4.98E+01
mice strain 216 and 219 death 10 CFU Meynell, G. G., & Meynell E. W. (1958).  The growth of micro-organisms in vivo with particular reference to the relation between dose and latent period. The Journal of Hygiene. 56(3),  all experiments