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Herpesviridae
200 mm in diameter
Double stranded DNA icosahedral capsid
Lipid-containing envelope (acquired from host cell nuclear membrane or cytoplasmic vacuoles)
Fusion: envelope glycoproteins and cell surface proteins
Present in all areas of world
No seasonal variation
No non-human vectors (human CMV)
Acquisition occurs at an earlier age in underdeveloped countries
Day-care and increased breast feeding has increased infection in younger children in developed countries
Most common cause of congenital infection in the United States
Direct or indirect person-to-person contact
Requires close or intimate contact with infected secretions:
- urine - oropharyngeal secretions
-semen - vaginal secretions
- tears - breast milk
- blood - transplanted organs
Virus excretion persists for years
· congenital
·Cytomegalovirus Perinatal Transmission
_ Intrauterine: 0.2-2.2% (only 5% symptomatic)
_ Maternal primary infection: 30-40%
_ Maternal recurrent infection: 0.9..1.5%
· CMV positive mother with >1 month of breast feeding: 30-70%
_ Congenital infection
_ Neonatal infection in premature infants
_ Mononucleosis syndrome
_ Immunosuppressed patients
· Interstitial pneumonitis
· Retinitis · Colitis
· Hepatitis · Meningoencephalitis
_ Intrauterine transmission
_ Maternal immunity (prior infection) affords protection (humoral ± cellular)
_ Effect of gestational age (primary infection)
- no effect on rate of transmission
- the earlier in gestation, the greater chance for severe sequela
_ Organs involved
· CNS - encephalitis; microcephaly
- sensorineural deafness
· Liver - hepatitis·
· Lung - pneumonitis
· Teeth - defect in enamel
· Spleen - splenomegaly