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