picture - Onset - Sudden with fever, chilly sensations, and prostration, catarrhal

viruses circulating in the population: Influenza virus has thus been described as an unvarying disease caused by a varying virus. Incubation period - 1 to 3 days. Clinical picture - Onset - Sudden with fever, chilly sensations, and prostration, catarrhal symptoms, headache, pains and dry cough. Sometimes erythematous rash. CLINICAL TYPES - 1. Febrile type - Only constitutional symptoms - fever, malaise, headache, severe bodyache, catarrh, congestion of eyes and throat; rapid prostration. Dry cough with few or no signs in chest. Fever lasts for 4 to G days, there may be relative bradycardia. 2. Respiratory type - (a) Bronchitis and bronchopneumonia. (b) Pleurisy; empyema not uncommon. (c) Pneumonia - (i) Fulminating rapidly fatal form in which pneumonia is present from the onset. (ii) Progressive form in which on the 2nd or 4th day signs of pneumonia begin to develop with copious fine crepitations usually basal. The sputum may be pinkish, frothy and copious, or tenacious mucus of several hues. (iii) Late form in which often after apparent recovery from the primary influenza, pneumonia suddenly supervenes on the 4th to 10th day after the onset. 3. Gl type -Temperature rarely above 37.5°C, severe anorexia and vomiting, abdominal discomfort and general prostration Tympanitis, diarrhoea and continued fever may simulate typhoid fever. 4. Malignant type - Severe toxemia, cyanosis and rapid cardiac failure. Always fatal. 5. Nervous type - Headache sometimes very severe, delirium, intense depression which may continue after the acute illness. A true meningitis may occur. Complications and sequelae - 1. Respiratory - Bacterial bronchopneumonia or lobar pneumonia, less often pure viral pneumonia. These may be concurrent with initial viral infection or follow after an interval. Staphylococcal pneumonia is a serious sequel and may be fatal, less severe infections may result in lung abscess. 2. Nervous system - Post influenzal psychoses, insomnia, irritability, polyneuritis, neurasthenia, meningitis and hemorrhagic encephalitis. 3. Circulatory system - Cardiac dilatation, irregularities, pericarditis, endocarditis. 4. Suppuration - Otitis media, mastoiditis, sinusitis. 5. Miscellaneous - Thrombophlebitis, arthritis, orchitis, myositis, nephritis, intestinal hemorrhage. Management - 1. Complete rest in bed. 2. Analgesics and sedatives. 3. Nose drops and throat gargles, or steam inhalations for congestion of nose and throat. Cough suppressive such as codein. 4. Antibiotics for secondary infections such as otitis media and pneumonia 5 Antiviral drug - Amantadine or rimantadine 200 mg/day orally useful for influenza A PREVENTION - (a) Vaccines - Polyvalent influenza virus vaccine 1 ml subcut; or 0.1-0.2 ml. intradermally given 1-2 weeks apart gives moderate temporary protection against current strains. (b) Anti-viral agents - Ribavirin 100-200 mg as effective as vaccination against Influenza A strains and may be started at the same time as vaccination to provide protection until immunity develops. 5. MEASLES Epidemiology - Age - mostly children between ages of 3-5 years, rare during first G months of life because of transferred passive immunity from mother. Causative agent - RNA paramyxovirus group. Transmission - Highly infectious and spread by direct contact or droplet infection. Patients suffering from measles shed virus from their respiratory tract during the prodromal period and for 24-48 hours after the rash appears Immunity - Immune response is not fully competent in early infancy, intercurrent infection or malnutrition further reduce these responses, increasing severity of the disease. Transplacental material IgG