Cytomegalovirus - CMV

Cytomegalovirus - CMV

 

Cytomegalovirus (CMV), generally asymptomatic in immunocompetent children and adults, is a potentially significant disease in immunocompromised hosts, neonates and pregnant females.

Epidemiology

  • Incidence – a large segment of the adult U.S. population has previously been infected with CMV
  • Transmission
    • Transplacental
    • Blood transfusion
    • Organ transplantation
    • Infectious droplet (normal childhood route)

Organism

  • Largest member of the Herpes virus family
  • Ability to remain latent (feature of all Herpes viruses)
  • Large nuclear inclusions produced in tissues by CMV are the hallmark of the disease

Clinical Presentation

  • Infection in utero or at birth
    • CMV infection may result in congenital abnormalities, including hepatosplenomegaly, deafness and mental retardation

 

CMV Diseases and Related Syndromes
CMV disease Principal syndrome Risk factors
AIDS Retinitis
GI disease
CNS disease		 <100 CD 4+ cells per mL
CMV+
Fetus Cytomegalic inclusion disease Primary early maternal infection
Organ transplant Pneumonia
GI disease
Disseminated disease		 Seropositive donor
Intensive immunosuppression
Bone marrow transplant Pneumonia
GI disease
Disseminated disease		 Older age
Seropositive donor
Graft vs. host disease
(Adapted with permission from Hirsch, et al., 2005, 1049)

 

  • Associated illnesses – hepatitis, pneumonia or a mononucleosis-like illness with little or no exudative pharyngitis or adenopathy (heterophile antibody negative mononucleosis)

Diagnosis

  • Laboratory testing
    • PCR – rapid diagnostic test
    • Antibodies – screening of pregnant women
      • CMV serologic testing included in pregnancy screening tests
      • Detects active or recently acquired CMV infections likely to be acquired by the fetus
    • Culture – gold standard for tissue screening

Treatment

  • CMV syndromes are often treatable
  • CMV prophylaxis is useful in high-risk patients

Prevention

  • Blood transfusions
    • Seronegative individuals transfused with blood from seropositive donors have a high risk of developing CMV infection
    • Serologic testing for CMV is important in screening blood for transfusion to neonates or to immunocompromised patients
  • Patients with altered cellular immunity (e.g., AIDS, recipients of organ transplants or cancer patients in active treatment)
    • Serologic testing is important for screening organ donors 
    • CMV infection is frequent and severe in transplant recipients
    • IgG titers may not be reliable as a means to detect reactivation of latent virus
      • Most AIDS patients are seropositive for CMV before HIV infection is diagnosed

See Also