# Dose response models for Cryptosporidium parvum

DuPont (1995) administered Cryptosporidium parvum (Iowa strain) to healthy university students by the oral route. The dose units were oocysts, and the response was infection. The exponential model was fit to these data by Teunis et al. (1999).

- k = 0.00419, 95% CI 0.00201 to 0.008911

The deviance of this model fit is 0.503 with 7 degrees of freedom.

The *p*-value for the null hypothesis of goodness of fit is 1.00.

The *p*-value for the null hypothesis that the beta-Poisson model fits no better than the exponential model is 0.72.

At a dose of 165.4, the expected percentage of hosts that would suffer the response would be 50%.

## References

DuPont, H.L. et al., 1995. The infectivity of Cryptosporidium parvum in healthy volunteers. The New England Journal of Medicine, 332(13), 855-859.[1]

Teunis, P.F., Nagelkerke, N.J. & Haas, C.N., 1999. Dose response models for infectious gastroenteritis. Risk Analysis: An Official Publication of the Society for Risk Analysis, 19(6), 1251-1260.