Using a specific example, explain the term "accidental host."
What will be an ideal response?
Answer: When an infectious agent invades a cell that is not necessary for its life cycle, it is considered to be infecting an accidental host. For example, Yersinia pestis has no life cycle dependency on humans and normally causes disease in rodents. However it is possible for Y. pestis to infect a human (the accidental host). Answers could include many other examples from the chapter, such as hantaviruses.
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Which of the following statements is false?
A. The use of antibiotics causes mutations in bacteria for antibiotic resistance. B. Once evolved, antibiotic resistance can be passed between different species of bacteria. C. Failure to complete a course of antibiotics selects for pathogens that are least susceptible to antibiotics. D. Some diseases, such as tuberculosis, have strains that are so antibiotic resistant that they are essentially untreatable. E. None of the answer options is false.
The sputum of a patient with acquired immunodeficiency syndrome (AIDS) is stained with Kinyoun's carbolfuchsin stain. Which organism would test positive using this stain?
a. Streptomyces spp. b. Pneumocystis jiroveci c. S. aureus d. Cryptosporidium spp.
Assuming there are still 100 individuals in the Florida panther population, about how much genetic diversity do you expect to be lost by genetic drift in 10 generations?
A. A little more than 10% B. A little more than 5% C. A little more than 1% D. A little more than 50% E. A little more than 15%
Trophic efficiency is:
a) how much food a carnivore can eat in one meal. b) the proportion of energy that is transferred between trophic levels. c) when plants capture energy from the sun. d) the breaking up of dead biomass by detritivores