Clinical infectious diseases

Despite vast improvements in public health, sanitation and vaccination, and huge technological advances in medicine, infectious diseases remain a major cause of morbidity and mortality. Many infectious diseases exhibit a characteristic pattern of symptoms and signs, aiding diagnosis: clinically obvious signs and symptoms, e.g. chickenpox; obvious system involvement without the pathogen being clear, e.g. pneumonia; obvious infection present, but not localized, e.g. fever. The extent of initial investigation, and provision of empirical treatment, depends on a number of factors: the severity of the manifestations; the time course of progression of the illness; the vulnerability of the underlying host; an immuno-suppressed host may display more subtle clinical signs of infection; public health or infection control significance.