Question 1

Which of the following best explains why Bordetella pertussis infections are considered an emerging infectious disease in recent years?

Accepted Answer

Lowered vaccination rates have led to increased incidence.

Question 2

A 7-year-old child presents with a severe sore throat, strawberry tongue, and a sandpaper-like rash. Which toxin is most likely responsible for these symptoms?

Accepted Answer

Streptococcal Pyrogenic Exotoxin (SPE)

Question 3

Which of the following diseases is caused by a spirochete and is transmitted primarily by tick bites?

Accepted Answer

Lyme Disease

Question 4

A patient presents with a persistent cough, night sweats, and weight loss. Acid-fast bacilli are seen on sputum smear. Which diagnostic test is most commonly used to screen for this disease in the United States?

Accepted Answer

Tuberculin Skin Test (TST)

Question 5

Which of the following statements about Streptococcus pyogenes is correct?

Accepted Answer

It can cause both pharyngitis and scarlet fever.

Question 6

A sexually active woman presents with mild, intermittent pelvic pain and is diagnosed with pelvic inflammatory disease (PID). Which pathogen is most likely responsible?

Accepted Answer

Neisseria gonorrhoeae

Question 7

Which of the following diseases is NOT nationally notifiable in the United States?

Accepted Answer

Scarlet Fever

Question 8

A patient develops severe watery diarrhea after a course of antibiotics. Which organism and toxins are most likely responsible?

Accepted Answer

Clostridium difficile; Toxin A and Toxin B

Question 9

Which of the following best describes the transmission route of Mycobacterium tuberculosis?

Accepted Answer

Airborne/droplet

Question 10

A 65-year-old patient develops pneumonia after a recent influenza infection. Which vaccine could have reduced their risk for this secondary bacterial pneumonia?

Accepted Answer

Pneumococcal conjugate vaccine (PCV13 or PCV23)

Question 11

Which of the following diseases is caused by an obligate intracellular parasite and is frequently asymptomatic in women, but can lead to PID?

Accepted Answer

Chlamydia

Question 12

A patient presents with a high fever, rash on the wrists and ankles, and a history of tick exposure. Which organism is most likely responsible?

Accepted Answer

Rickettsia rickettsii

Question 13

Which of the following is a unique diagnostic feature of tuberculosis on chest X-ray?

Accepted Answer

Ghon complex (calcified tubercles)

Question 14

Which of the following diseases is associated with a 'bull's-eye' rash and can lead to arthritis if untreated?

Accepted Answer

Lyme Disease

Question 15

Which of the following statements about the DTaP vaccine is correct?

Accepted Answer

It protects against diphtheria, tetanus, and pertussis.

Question 16

A patient with a history of recent hospitalization develops severe diarrhea. Which of the following best explains the pathogenesis of the causative organism?

Accepted Answer

Production of Toxin A and Toxin B by Clostridium difficile damages the intestinal mucosa.

Question 17

Which of the following diseases is NOT zoonotic?

Accepted Answer

Gonorrhea

Question 18

Which of the following is a distinguishing feature of Neisseria gonorrhoeae compared to Chlamydia trachomatis?

Accepted Answer

It is a gram-negative diplococcus.

Question 19

Which of the following best describes the transmission of Clostridium difficile?

Accepted Answer

Direct or indirect fecal-oral transmission, especially in healthcare settings.

Question 20

A patient presents with a severe cough described as a 'whooping' sound. Which of the following is the most likely causative agent?

Accepted Answer

Bordetella pertussis

Major Infectious Diseases: Causative Agents, Transmission, and Clinical Features

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