Comparison of tissue culture and animal models for assessment of Cryptospridium parvum infection

Abstract

The current increased interest for using tissue culture as a surrogate for mouse infection to assess Cryptospridium viability suggests that a comparison of the two models is essential for data interpretation. Therefore, a need remains for a statistical comparison that can demonstrate if infection and inactivation predicted by new tissue culture models are comparable with those predicted by animal models. Data from a total of 31 dose–response trials using both tissue culture and mouse models to assess C. parvum infectivity were compared. The dose needed to infect 50% of the tissue cultures (ID 50) was also compared to each ID 50 in mice. Average ID 50s developed using the logit dose–response method for tissue culture and mice were 8 and 107, respectively, suggesting that tissue culture was more sensitive to infection. However, correlation ( r) between tissue culture and mouse infectivity was statistically significant (0.9167 [95% CI=0.8428 to 0.9594, p<0.0001]). Comparison of oocyst disinfection by UV and chlorine dioxide showed no significant difference between inactivation predicted by tissue culture and mouse models ( p=0.8893; t=0.0141; n=21). These results demonstrate that tissue culture can successfully be used to measure C. parvum infection and can be used for determining inactivation in disinfection studies.