《儿科学》课程教学课件（PPT讲稿）18 Varicella

VARICELLA(CHICKENPOX)

VARICELLA (CHI CKENPOX)

OverviewPrimary infection with varicella-zoster virus (VzV)causes varicella (chickenpox)Varicella is characterized by the appearance onthe skin and mucous membranes of successsivecrops oftypical vesicles,generallyaccompanyedbya mild constitutionalreaction.The virus establishes latent infection indorsalroot ganglia; its reactivation causes herpes zoster(shingles)

Ove r view Primary infection with varicella-zoster virus (VZV) c a u s e s varicella (chickenpox). Varicella is characterized by the a p p ea ra nce on the skin a n d mu cou s memb ra n es of su ccesssive crop s of typical vesicles, generally a ccomp a n yed by a mild constitutionalreaction. The virus esta b lishes latent infection in dorsal root ganglia; its reactivation c a u s e s h erp es zoster (shingles)

ETIOLOGY

ETIOLOGYClassification: double-stranded DNAvirusthe viral genome encodes more than 70 proteinshuman herpesvirus;alpha herpesvirusSerotype: Only onebecause ofits similarities to the prototype for this group,which isherpes simplex virus (HSV)

ETI OLOGY Classification: double-stranded DNAvirus the viral genome encodes more than 70 proteins human herpesvirus; alpha herpesvirus Serotype: Only one becaus e of its similarities to the prototype for this group, which is herpes simplex virus (HSV)

ETIOLOGY Location: Patients respiratory secretionsBlood, herpes fluid. Characterization:Sensitive to heat , acid and disinfectant

• Loc a tion: Pa tients re s p ira tory s e c re tions , Blood, her p es fluid • Characterization: Sensitive to heat , acid and disinfectant ETI OLOGY

Epidemiology

Epidemiology?Infectious sources----Patients. infective stage:The infective stage is from about 24 hr beforethe appearance of the rash until all lesionsare crustedRoutes oftransmissionIt is spread by dropletor by direct contact

Epidemiology • Infectious sources- Patients • infective stage: The infective stage is from about 24 hr before the ap p earance of the r ash until all lesions are crusted • Routes of transmission It is sp r ead by droplet or by direct contact

Epidemiology. Population susceptibility90% of reported patients are under 10-yr ofage.Thepeak age of incidence is 5-9yr. Peak season: In winter andspring

Epidemiology • Population susceptibility 90% of reported patients are under 10-yr of age. The peak age of incidence is 5-9 yr. • Peak season: In winter and spring

Pathogenesis8>

PATHOGENESISV-Z-Vrespiratory secretions or skin lesionmucosalinoculationregional lymphnodesviremiamononuclearcellsviremiarespiratorymucosal,skin,organs

respiratory se c r e tions or skin lesion muc osa l inoculation regional lymph node s viremia mononuc le a r cells viremia respiratory muc osa l , skin, or ga ns PATHOGENESIS V-z-v