• Clinical science

Cytomegalovirus infection


Infection with the cytomegalovirus (CMV or human herpes virus 5) is generally asymptomatic in immunocompetent hosts, but can cause mild mononucleosis-like symptoms. Like all Herpesviridae infections, CMV persists for the lifetime of its host; reactivation may therefore occur. Immunocompromised individuals (e.g., AIDS, post-transplantation) are especially at risk of illness following reactivation or initial infection, which can include severe manifestations such as CMV retinitis (risk of blindness) or life-threatening CMV pneumonia. Treatment with ganciclovir or valganciclovir should therefore begin promptly on clinical suspicion of a CMV infection.

Congenital CMV infection is discussed in another article.


  • Prevalence of CMV infection in the general population: 40–100%
  • Seroprevalence increases with age with more than 90% in individuals > 80 years

Epidemiological data refers to the US, unless otherwise specified.




  • CMV binds to integrins; activation of integrins induction of cellular morphological changes → activation of signal transduction pathways; such as FAK (focal adhesion kinase) and apoptotic pathways → cell damage clinical manifestations depending on the organ/tissue affected. [4][5]
  • After primary infection resolves, CMV remains latent in mononuclear cells (e.g., myeloid cells). Reactivation can occur if the patient becomes immunocompromised. [6]

Clinical features

CMV infection is usually asymptomatic. Severe manifestations occur in immunocompromised states (e.g., following organ transplantation, AIDS).

For information about congenital CMV infection, see the corresponding article.

In immunocompetent patients

In immunocompromised patients

One or more of the following clinical manifestations may be present:

Among HIV-positive patients, manifestations of CMV disease usually occur when the CD4 count is ≤ 50!


In immunocompetent patients, CMV infection may present similarly to EBV infection. However, in CMV infection the monospot test will be negative!

Serological tests may be unreliable in immunosuppressed patients!


  • In immunocompetent patients: No specific treatment is needed. [3][2]
  • In immunosuppressed patients [11]
    • Optimize antiretroviral therapy regimen to increase CD4 count above 100 cells/mm3
CMV infection Regimen Duration
CMV retinitis
  • At least 3–6 months
CMV colitis
  • 21–42 days
CMV esophagitis
CMV pneumonia
  • Until CD4 count > 100 cells/mm3 and symptoms improve
CMV encephalitis