The following set of words can be used synonymously in epidemiology

in latent infection the host does not shed the infectious agent which lies dormant within the host without symptoms.the subclinical cases are referred to as inapparent,cove,missed or aboive cases.they are equally impoant as sources of imfections.the term primary case is the first case of a communicable disease and index case refers to the first case that comes to the attention of an investigator.ref;parks textbook ,22 nd ed,pg no 92