Questions
Cytomegalovirus: Questions
Study questions about Cytomegalovirus: multiple-choice, clinical scenarios, short-answer and exam-style.
Mock Exam mode
Sit this set one question at a time. Multiple-choice questions mark themselves; written questions reveal a tickable mark scheme so you can score your own answer. You get a combined score at the end.
3 questions: 2 MCQ, 1 written.
- High priorityMCQ
A previously well young adult has two weeks of fever, malaise and a mild hepatitis, and a heterophile antibody (Monospot) test is negative. Which infection best explains a heterophile-negative mononucleosis syndrome?
- A. Cytomegalovirus
- B. Epstein–Barr virus
- C. Hepatitis A virus
- D. Acute HIV infection
- E. Adenovirus
Show answer
Correct answer: A
Why A
Cytomegalovirus is the leading cause of heterophile-negative infectious mononucleosis. It produces fever, malaise, a biochemical hepatitis and atypical lymphocytes, but usually without the prominent pharyngitis and lymphadenopathy of Epstein–Barr virus, and it tends to occur about a decade later in life. It is confirmed by CMV IgM with low-avidity IgG, or by detecting CMV DNA.
Epstein–Barr virus causes the heterophile-positive form. Hepatitis A, adenovirus and acute HIV can share some features but are not the classic cause of this syndrome.
- MCQ
Where does cytomegalovirus (CMV) principally establish lifelong latency?
- A. Sensory dorsal root ganglion neurons
- B. Resting memory B lymphocytes
- C. Renal tubular epithelial cells
- D. Hepatocytes and Kupffer cells
- E. Monocytes and CD34 myeloid progenitors
Show answer
Correct answer: E
Why E
As a betaherpesvirus, CMV is latent in the myeloid lineage: in CD34 bone-marrow progenitors and the monocytes derived from them. Reactivation accompanies differentiation into macrophages and dendritic cells, which is why it reawakens during inflammation and immunosuppression.
For contrast, the alphaherpesviruses (herpes simplex, varicella-zoster) are latent in sensory ganglion neurons, and Epstein–Barr virus is latent in memory B lymphocytes.
Exam-styleWhy is there no licensed cytomegalovirus (CMV) vaccine despite the disease burden, and what are the leading candidate strategies? [5]
Model answer
A complete answer gives the biological obstacles and then the main candidate approaches.
Why it is difficult
- Natural immunity is only partial: reinfection and reactivation occur in the immune, so the protective correlate is uncertain and a vaccine must outperform natural infection.
- The virus establishes lifelong latency beyond the reach of the immune response.
- Primary infection is usually silent, making it hard to target.
- There is no good animal model of the human virus.
Candidate strategies
The leading approaches target glycoprotein B and the pentameric complex, the determinants of entry and of neutralising antibody, and include messenger RNA (mRNA) platforms. The clearest signal so far is a glycoprotein B subunit vaccine that halved primary infection in seronegative women and transplant candidates. The aim is to prevent maternal primary infection and congenital disease.