Airborne spread or skin-to-skin contact. Like EBV, infection is more severe if primary infection of adult. Patients at risk are (1) adults, (2) pregnant women in their 3rd trimester and (3) immunocompromised patients. The mortality rate for varicella pneumonia in leukemic children receiving chemotherapy is 1,000 times higher than in healthy children. But children with isolated agammaglobulinemia are not at risk.
Sequence of events
- Airborne transmission
- Viremia-virus in the blood, replication in organs, incubation period.
- Continued replication results in emergence of virus from capillaries to the skin.
Complications of Varicella
- Bacterial superinfection of lesions
- Varicella pneumonia
- Neonatal varicella
- Reyes syndrome (from aspirin intake)
Reyes Syndrome is a a neuroencephelopathy. Liver failure results in toxic buildup of bilirubin, damaging brain cells.
Live, attenuated virus-so limited infection, not as good an immunization as chickenpox disease. Prevents 70-90% of chickenpox, reduces severity in rest. Can still reactivate to cause shingles: Infections are unilateral, painful vesicular eruptions localized to the dermatome, usually in the head or upper trunk; Severe systemic infections are observed in immune suppressed individuals.