课件：流行性感冒(禽流感)课件PPT.ppt

* This figure illustrates the frequency of symptoms found in 5 different studies of adults with virologically confirmed influenza A infection.5 The most prominent findings are cough, malaise and fever. Vomiting, diarrhea and abdominal pain are relatively uncommon findings in adults and generally indicate some other type of infection. Type B viruses usually produce less severe clinical illness than that associated with type A infections. However, type B viruses have been associated with epidemic infections that cause widespread hospitalization and death.6 Slide 4 Lecture Notes * As shown here, the most common signs and symptoms in children less than 5 years of age are fever and rhinitis.5 In very young infants, rhinitis may in fact be the only respiratory symptom.5 In contrast to adults and older children, patients in this age group are more likely to experience nausea, vomiting and diarrhea, fever, anorexia, and various respiratory syndromes.5,7 Of course, the presence of these visible symptoms is easy to determine; invisible constitutional complaints such as malaise or myalgia may indeed be present but are more difficult to identify in young children and infants. Pediatric experts may not agree on which signs and symptoms constitute a case definition of influenza. However, a panel of pediatric experts recently agreed that the presence of fever, cough and nasal congestion were indicative of flu. Slide 5 Lecture Notes * While older individuals also experience classic flu symptoms, respiratory problems may not occur. Rather, elderly patients may present with high fever, lassitude, confusion and nasal obstruction.4 A fever higher than 99.0°F is a distinguishing feature of influenza in elderly adults who generally have a lower basal body temperature. This was symptomatic of influenza in a nursing home population,8 while a fever of at least 100.4°F helped to distinguish flu from respiratory syncytial virus in hospitalized community-dwelling adults 65 years and