Enumeration of Acanthamoeba castellanii in the presence or absence of Cryptosporidium parvum oocysts over time in the unfavorable phagocytosis condition (1A) and in the favorable phagocytosis condition (1C) and enumeration of C. parvum oocysts in the presence or absence of A. castellanii over time in the unfavorable phagocytosis condition (1B) and in the favorable phagocytosis condition (1D). p-value: *** < 0.001. (magnification ×200 for A. castellanii and ×400 for C. parvum).