Viral Gastroenteritis & Hepatitis Exam Bank Solution Manual Already Passed

Gastroenteritis & Hepatitis Exam Bank Solution Manual Already Passed Gastroenteritis - Answers inflammation of the lining of the intestine, leading to diarrhea - More than ½ of all cases of acute diarrhea are of viral origin - Incubation period of 1-4 days before abrupt onset of vomiting, followed by diarrhea and mild fever - Dehydration results due to severe loss of electrolytes and fluids (can be fatal if untreated) Viruses that cause gastroenteritis - Answers 1. Reoviridae [rotavirus] 2. Adenovirus (Types 40 and 41) 3. Calcivirus [Norovirus] 4. Astrovirus Viruses that cause gastroenteritis: Reoviridae - Answers Respiratory and enteric orphan virus [dsRNA] - Rotavirus [segmented dsRNA]: severe gastroenteritis in young children Viruses that cause gastroenteritis: adenovirus (Types 40 and 41) - Answers DNA genome (nuclear replication) - endemic diarrheal illness in children Viruses that cause gastroenteritis: calcivirus - Answers ss +RNA genome - norovirus: acute gastroenteritis in all age groups Viruses that cause gastroenteritis: astrovirus - Answers Ss + RNA genome - mild diarrheal illness in infants, young children, and the elderly Rotavirus statistics - Answers 75-90% children infected <5-yr-old. Worldwide: - 39% of children hospitalized for acute gastroenteritis. - Kills >1/2 million children per yr. mainly in developing countries USA: - Affects 1.2 million children per year - ~10,000 hospitalized with severe illness. * infections predominate during winter season * symptomatic infections most common in children between 6 months and 2 years Rotavirus: transmission site of infection - Answers Transmission: - fecal-oral - nosocomial Site of infection: tips of villi of small intestine - 1-4 days incubation *rotaviruses are ubiquitous Rotavirus: mechanisms of pathogenesis - Answers 1. Direct Cellular Damage: damage to transport mechanisms in epithelial cells (impaired Na and glucose absorption) 2. Activation of Intestinal Nerves: stimulation of enterocytes to secrete water 3. Fluid accumulation in the lumen of the small intestine resulting in 10-20 diarrheal episodes per day and severe dehydration Rotavirus structure - Answers