Cytomegalovirus (CMV) - Herpes Viruses

Cytomegalovirus (CMV)

·        Transmission:

o   Blood: transfusions, intra-uterine, perinatal, needle sharing

o   Cervical secretions and semen

o   Saliva (eg close contact with kids)

o   Urine (eg infants to adults)

o   Organ donation (transplantation)

·        Immunocompetent:

o   Kids:

§  Common in preschoolers, usually asymptomatic.  May give URTI

§  Prolonged excretion in saliva and urine common

o   Adults:

§  Usually asymptomatic, if not then usually self-limiting

§  May be fever (up to 2 weeks, ie a differential of PUO)

§  Sore throat, cervical lymphadenopathy uncommon

§  Atypical mononucleosis on blood film

§  Differential: EBV, HIV, toxoplasmosis

o   Pregnancy:

§  Congenital infection (ie crosses placenta) in 20 – 40% 

·        > 90% show no signs at birth, but watch for long term neurological sequalae (eg sensori-neural deafness, retardation)

·        Severe cases: respiratory distress, jaundice, microcephaly, etc

·        Part of TORCH complex: Toxoplasmosis, Rubella, CMV, HSV

§  Perinatal infection (eg during vaginal delivery):

·        Full term: usually mild

§  Pre-term: may be severe

·        Immunodeficient:

o  AIDS: one of the most common infections ® CMV retinitis (common), CMV encephalitis (rare), CMV colitis (rare) 

o  Transplant: greatest risk if they‟re CMV negative and CMV positive organ ® interstitial pneumonia and hepatitis (in liver transplant)

·        Transfusion: blood is not routinely screened for CMV antibody. Should give CMV –ive blood to prem babies (<1500 g) and seronegative transplant recipients with seronegative transplants

·        Lab diagnosis:

o  Serology:

·        IgG            IgM

·        No infection       -           -

·        Past infection    +          -

·        Acute primary or reactivated           +          +

·        infection            

o  Cell culture – slow (>7 days).  Culture lung biopsy or peripheral blood leucocytes 

o  PCR for CMV DNA on peripheral leucocytes, amniotic fluid, CSF (very specific, less sensitive, very expensive)

·        Treatment:

o  Ganciclovir: bone marrow toxicity

o  Foscarnet (nephrotoxic)

o  Ganciclovir prophylaxis used for –ive patients with +ive organs