A 12-year-old girl has a three-day history of fever, sore throat, chills, myalgias, and general
malaise. Her condition may have been prevented by receiving a yearly vaccine designed to induce
an antibody response to a protein capable of binding sialic acid residues. Which of the following
best describes the causative virus?
- A) RNA; non-enveloped; positive-sense; non-segmented
- B) RNA; non-enveloped; positive-sense; segmented
- C) RNA; non-enveloped; negative-sense; non-segmented
- D) RNA; non-enveloped; negative-sense; segmented
- E) RNA; enveloped; positive-sense; non-segmented
- F) RNA; enveloped; positive-sense; segmented
- G) RNA; enveloped; negative-sense; non-segmented
- H) RNA; enveloped; negative-sense; segmented
0 voters
EXP:
This child has an influenza viral infection.
Two of the proteins encoded by the segmental genome, hemagglutinin and neuraminidase, are
embedded in the viral envelope and available for antibody binding.1
Influenza viral infection begins when hemagglutinin binds to sialic acid residues on
carbohydrate side-chains of cell-surface glycoproteins and glycolipids.2
Following viral replication, neuraminidase cleaves sialic acid residues from the cell so that newly
formed viral particles don’t attempt to reinfect the same cell.3, 4
Influenza vaccine
• Currently licensed vaccines are designed to induce antibodies against hemagglutinin.5
• Available in two main forms: killed (intramuscular) and live-attenuated (intranasal spray).6
• Killed vaccine may be given to anyone >6 months of age, including pregnant women.7
• Live-attenuated may be given to any non-pregnant, non-immunocompromised persons age 2-
49.7, 8, 9, 10
Bottom line: Influenza is a segmented RNA virus. Current vaccines are designed to produce
antibodies to hemagglutinin. Killed vaccine may be given to anyone >6 months of age, including
pregnant women. Live-attenuated vaccine may be given to any non-pregnant, nonimmunocompromised persons age 2-49