Question 1

Which type of tetanus involves Clostridium tetani organisms present in the middle ear and can cause facial paralysis?

Accepted Answer

Cephalic tetanus occurs when C. tetani are present in the middle ear and cause paralysis of facial muscles due to inhibition of nerve transmission in branches of the fifth cranial nerve.

Question 2

A vaccine for diphtheria may be combined with vaccines for which of the following agents? 
I. Pertussis
II. Hepatitis B
III. Haemophilus

Accepted Answer

Combination vaccines for diphtheria may also contain pertussis, tetanus, hepatitis B, and inactivated polio.

Question 3

Why is the oral polio vaccine no longer used in the United States?

Accepted Answer

The oral polio vaccine contains attenuated viruses that have the ability to replicate and may revert to the virulent form. This puts the recipient, as well as immunocompromised patients in contact with the vaccine recipient, at risk for infection.

Question 4

Patients with tetanus experience characteristic unpredictable muscle spasms, which are caused by:

Accepted Answer

The A subunit of tetanospasmin inactivates synaptobrevin, which prevents the release the GABA and glycine, which are inhibitory neurotransmitters. This lack of inhibition leads to uncontrolled release of acetylcholine, a neurotransmitter that stimulates muscle contractions under normal conditions but causes spasms during uncontrolled release. These continued spasms lead to spastic paralysis of the muscles involved.

Question 5

Which of the following infectious agents are capable of forming spores? 
I. Clostridium tetani
II. Bordetella pertussis
III. Corynebacterium diphtheriae

Accepted Answer

Only C. tetani can form spores under conditions that lack proper nutrition. The spores can survive in soil for years. When a person suffers a puncture wound with a contaminated object, the spores can revert from their dormant form to growing, thriving bacteria, which then cause illness in the person with the infected wound.

Question 6

Which of the following are pathogens that cause meningitis? 
I. Polio virus
II. Rubeola virus
III. Haemophilus influenzae type b

Accepted Answer

Meningitis is an inflammation of the meninges covering the brain, and while it can be viral or bacterial, bacterial is the most serious form. Of the organisms listed, only H. influenzae type b causes meningitis. Polio can cause paralysis, so it does affect the nervous system, but it does not cause meningitis. One of the severe complications of rubeola infection can be encephalitis, but not meningitis.

Question 7

The diphtheria toxin targets cellular machinery, leading to the outcome of:

Accepted Answer

The A subunit of the diphtheria toxin cleaves the nicotinamide adenine dinucleotide (NAD) molecule into nicotinamide and ADP-ribose. The A subunit attaches ADP-ribose molecules to the elongation factor-2 (EF-2), which is important for joining amino acids during protein synthesis. The attached ADP-ribose molecules inactivate EF-2, which decreases or stops protein synthesis in the target cell, eventually leading to cell death.

Question 8

Which of the following are toxoid vaccines? 
I. Tetanus
II. Pertussis
III. Diphtheria

Accepted Answer

The tetanus, pertussis, and diphtheria vaccines are all toxoid vaccines. Toxoid vaccines are acceptable for these organisms because in each of the disease states the toxins are the main damaging agent.

Question 9

Which of the following are live, attenuated vaccines?

Accepted Answer

The mumps and measles vaccines are live, attenuated vaccines, along with rubella and the nasal influenza vaccine. Hepatitis B, rotavirus, papilloma virus, IM influenza, and hepatitis A are all either killed or subunit vaccines.

Question 10

What is the mechanism of suppression of the immune system by the measles (rubeola) virus?

Accepted Answer

The measles virus is capable of infecting lymphocytes, and when infected, these lymphocytes undergo apoptosis, so the immune system is not able to respond properly. Therefore, the primary infection is more difficult to eliminate and the patient is at greater risk for secondary infections.

Question 11

The role that herd immunity plays in vaccination is to:

Accepted Answer

The concept of herd immunity depends upon vaccination of a "large enough" portion of the population so that if a person acquires an infectious agent, the patient is surrounded by enough vaccinated people that there is no susceptible person in contact with the patient. Therefore, the agent is not transmitted to other people and there is not a larger outbreak of the illness.

Question 12

In a vaccine such as Menactra, what is the main purpose of linking the capsular polysaccharides of Neisseria meningitis to the diphtheria toxin?

Accepted Answer

The capsular polysaccharides are T cell-independent antigens, and linking them to a toxin will stimulate a T cell-dependent immune response, which is important for memory cell formation and long-term protection.

Question 13

Which of the following is a virulence factor for Haemophilus influenzae type b?

Accepted Answer

Polyribosyl phosphate is the major virulence factor for H. influenzae type b. Pertactin is a virulence factor for pertussis. A polysaccharide capsule is a virulence factor for pneumococcus, and LOS endotoxin is a virulence factor for Neisseria meningitides.

Question 14

Which form(s) of polio result(s) in paralysis of the diaphragm and death caused by respiratory arrest? 
I. Spinal polio
II. Bulbar polio
III. Bulbospinal polio

Accepted Answer

While all three are paralytic forms of polio, only the bulbospinal form affects the spinal cord at C3 to C5 and paralyzes the diaphragm, potentially resulting in respiratory arrest and death.

Question 15

Pertussis toxin (PTx) causes what outcome in cells?

Accepted Answer

The pertussis toxin binds NAD to regulatory protein G1. The subsequent inactivation of G1 allows uncontrolled conversion of ATP to cAMP. The accumulation of cAMP disrupts normal cellular function and alters hormone activity, leading to the symptoms of pertussis.

Question 16

Bordetella pertussis uses filamentous hemagglutinin for what purpose?

Accepted Answer

B. pertussis uses filamentous hemagglutinin to attach to cells in the respiratory tract. Fimbraie and pertactins facilitate secondary points of attachment. Once attached, toxins cause damage to respiratory tissue.

Question 17

Immunization against ____________ is protective against otitis media.

Accepted Answer

Pneumococcus is the only agent listed that causes otitis media. Pneumococcus also causes a variety of other illnesses, including meningitis, cellulitis, endocarditis, and abscesses.

Question 18

Measles and German measles are clinically similar because:

Accepted Answer

While the spots of the German measles are smaller than those of measles, both rashes begin around the head and neck area and travel down the body to the torso and the limbs.

Question 19

Corynebacterium diphtheriae colonizes:

Accepted Answer

C. diphtheriae is transmitted through the respiratory tract and colonizes the tonsils and pharynx. The exotoxin is then transported to the heart, muscle, adrenal glands, kidneys, liver, and spleen. The toxin causes extensive damage in these areas, along with the damage caused in the respiratory tract.

Question 20

What is the purpose of the polysaccharide capsule of Streptococcus pneumoniae?

Accepted Answer

The polysaccharide capsule is important to a bacterium because it helps the bacterium to evade the immune response. The capsule prevents phagocytes from ingesting the pathogen and prevents complement fragments from binding to the pathogen surface. Therefore, the bacterium is better able to establish infection before the adaptive immune response is activated.

Quiz 25: Vaccine-Preventable Diseases