The ID₅₀ for Campylobacter sp. is 500 cells; the ID₅₀ for Cryptosporidium sp. is 100 cells. Which of the following statements is false?
a. Both microbes are pathogens.
b. Both microbes produce infections in 50% of the inoculated hosts.
c. Campylobacter is more virulent than Cryptosporidium.
d. Campylobacter and Cryptosporidium are equally virulent; they cause infections in the same number of test animals.
e. Cryptosporidium infections are acquired more easily than Campylobacter infections.