دانلود پاورپوینت طیف بیماریها و دامنه عفونت

Unidentified cases may be different to identified ones, both in terms of the natural history or spectrum of disease. 

Where symptoms and disease progression and outcome are related, the undiagnosed cases are likely to be less severe. 

When symptoms and signs are not evident in the early stages of disease, as in high blood pressure or chronic glaucoma, undiagnosed cases may be just as severe as diagnosed ones. 

Epidemiological studies based on selected cases from the tip of the iceberg may give an erroneous view.