The first step in confounding an epidemic investigation is to-

.the first step in the diagnosis of an epidemic is the verification of the diagnosis.it may sometimes happen that the rep may be spurious,and arise from misinterpretation of signs and symptoms by the lay public.it is therfore necessary to have the verification of diagnosis on the spot as quickly as possible.it is not necessary ton examine all cases to arrive at a diagnosis.a clinical examination of a sample of cases may well sufficce,laboratory investigations wherever applicable,are most useful to confirm the diagnosis but the epidemiological investigations should not be de4layed untill the laboratory results are available. ref:parks textbook,22nd ed,pg no 119