Cytomegalovirus (CMV)

Classification

• Cytomegalovirus (CMV) or human herpesvirus-5 (HHV-5) 
• Enveloped
• Linear, double-stranded DNA virus
• Largest virus that causes human infections

Transmission and Diseases associated

Transmission	Patient	Disease
In utero- Most commonly infects in last trimester Most common cause of congenital viral infection	Fetus	Infected with no defect Severe cytomegalic inclusion diseases: Jaundice Hepatosplenomegaly(Most coomon) Thrombocytic purpura Pneumonitis CNS damage Death
Birth process Milk	Babies	Serious disease uncommon Hetrophile negative mononucleosis
Reactivation in transplanted organ	Transplant patient	Interstitial Pneumonitis Systemic diseases
Reactivation or new infection	AIDS patient	CMV retinitis Systemic diseases

Epidemiology

• Incidence-Very common
• Risk factors

1. Immunosuppression
2. Men who have sex with other men
3. Poor socioeconomic status
4. Working in childcare
5. Transplant recipients-Prone to CMV pneumonia

Pathogenesis

• CMV-caused diseases can either result from a primary infection or reactivation of a latent infection
• Replication of host cells (including epithelial cells, macrophages, and neurons) result in viremia and symptoms from primary infection
• Cellular immunity is crucial in clearing this virus

Diagnosis

1. Physical exam-Fever, cervical lymphadenopathy, hepatosplenomegaly and maculopapular rash

2.Labs

• Lymphocytosis with atypical lymphocytes
• Thrombocytopenia
• Transaminitis
• Negative heterophile antibody
• CMV-specific immunoglobulin M (persists for 4-6 months)
• CMV-specific immunoglobulin G (2-3 weeks)
• Ig G antibody test is of little diagnostic value as positive results also reflects maternal antibodies.
• CMV viral DNA in blood by polymerase chain reaction in  neonate
• Nucleic acid detection from the intraocular fluid in CMV retinitis

3. Histology

• A large cell containing a large basophilic intranuclear “owl’s eye” and intracytoplasmic inclusion bodies.

Treatment

• Mainstay of treatment is supportive care
• Medical

Antiviral medications-indications

• Immunocompromised patients
• Severe disease or organ damage

Drugs

• Gancyclovir 
  
• Gancyclovir  used intravitreally for retinitis
• Valganciclovir

Complications

• Thrombosis
• Colitis
• Permanent vision changes

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