Measure of lnfectivity of a disease:

Ref: Park 'Textbook of Preventive and Social Medicine', 22nd edition, Pg: 58, 55, 96Explanation:Incidence rateNumber of new cases occurring in a defined population during a specified period in timePrevalence rateIt includes old and new cases, it depends on Incidence and duration of disease Prevalence = incidence X durationSecondary attack rateIndicates communicability or infec- tivrtyNo. of contacts d eve lo Dina disease in one maximum IP X 100 Total no. susceptible contactsCase fatality rateSeverity of the disease, killing power of the diseaseIndicators of severity of disease1. Case fatality rate2. Disability rate