21. Principles of Disease

All of the following are phases of bacterial pathogenesis except which of these answers?

During the Covid-19 pandemic, individuals around the world were advised to wear masks covering their nose and mouth. Why is this medical advice important for decreasing the spread of the SARS-CoV-2 virus?

Which of the following is not true about adhesin molecules?

The process by which infectious agents are ingested by host cells is termed

Which of the following statements is false?

a. E. coli never causes disease.

b. E. coli provides vitamin K for its host.

c. E. coli often exists in a mutualistic relationship with humans.

d. A disease-causing strain of E. coli causes bloody diarrhea.

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.

Which of the following statements is true?

a. The primary goal of a pathogen is to kill its host.

b. Evolution selects for the most virulent pathogens.

c. A successful pathogen doesn't kill its host before it is transmitted.

d. A successful pathogen never kills its host.

Compare pathogenicity with virulence.