History

Fact Explanation
Acute gastrointestinal features appear as an outbreak. Noroviruses (aka Norwalk agent) are the most common cause of viral gastroenteritis in the United States, [1] and are major causative agents similarly worldwide. [2] Norvovirus is an exclusive human pathogen causing food-borne and water-borne diseases that occur in various epidemiological settings, but commonest amongst school children and marine travelers. [3] [4] [5]
Self-limiting diarrhea and vomiting. The commonest symptoms of the infections reported were acute self-limiting watery diarrhea and vomiting. The symptoms resolved themselves by 24-36 hours. [1] [3] The symptoms are dose-dependent with the amount of bacteria ingested. [3] [4]
References
  1. ATMAR RL, OPEKUN AR, GILGER MA, ESTES MK, CRAWFORD SE, NEILL FH and GRAHAM DY. Norwalk virus shedding after experimental human infection. Emerg Infect Dis. [online] 2008 Oct;14(10):1553-7. [viewed April 26, 2014] Available at doi: 10.3201/eid1410.080117.
  2. TEUNIS PF, MOE CL, LIU P, MILLER SE, LINDESMITH L, BARIC RS, LE PENDU J and CALDERON RL. Norwalk virus: how infectious is it? J Med Virol. [online] 2008 Aug;80(8):1468-76. [viewed April 26, 2014] Available at doi: 10.1002/jmv.21237.
  3. HERWALDT BL, LEW JF, MOE CL, LEWIS DC, HUMPHREY CD, MONROE SS, PON EW and GLASS RI. Characterization of a variant strain of Norwalk virus from a food-borne outbreak of gastroenteritis on a cruise ship in Hawaii. J Clin Microbiol. [online] 1994 Apr;32(4):861-6. [viewed April 26, 2014] Available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC263153/
  4. KHAN AS et al. Norwalk virus-associated gastroenteritis traced to ice consumption aboard a cruise ship in Hawaii: comparison and application of molecular method-based assays. J Clin Microbiol. [online] 1994 Feb;32(2):318-22. [viewed April 26, 2014] Available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC263031/
  5. ELMIRA T et al. Norovirus Transmission on Cruise Ship. Emerg Infect Dis. [online] Jan 2005; 11(1): 154–157. [viewed April 26, 2014] Available at doi: 10.3201/eid1101.040434

Examination

Fact Explanation
Features of dehydration. i.e. dry skin, sunken eyes, reduced lacrimation, low blood pressure and tachycardia. The gastropathy caused by Norwalk agent is self-limiting and mild, so examination findings are few and non-specific. Mostly what's evident are signs of dehydration. [1] [2] [3]
References
  1. MACKENZIE A, BARNES G and SHANN F. Clinical signs of dehydration in children. Lancet. [online] 1989 Sep 9;2(8663):605-7. [viewed April 27, 2014] Available at doi:10.1016/S0140-6736(89)90723-X
  2. BARDGET ME et al. Coping with Dehydration: Sympathetic Activation and Regulation of Glutamatergic Transmission in the Hypothalamic PVN. American Journal of Physiology - Regulatory, Integrative and Comparative Physiology [online] 26 March 2014. [viewed April 27, 2014] Available at DOI: 10.1152/ajpregu.00074.2014
  3. NIESCIERENKO M and BACHUR R. Advances in pediatric dehydration therapy. Curr Opin Pediatr. [online] 2013 Jun;25(3):304-9. [viewed April 27, 2014] Available at doi: 10.1097/MOP.0b013e328360a1bd.

Differential Diagnoses

Fact Explanation
Gastroenteritis due to Escherichia coli infection E.coli is a major pathogen in food-borne bacterial gastroenteritis. [1] Various strains produce various clinical scenarios, but all syndromes are characterized by presence of fever because of the immune response to the bacteria, and long lasting symptoms, both not present in self-limiting mild gastropathy of Norvovirus. [2] [3]
Salmonella spp infection Typhoid is characterized by high swinging fever of step ladder pattern, initial abdominal pain and diarrhea later. Unlike Norvovirus infection, it lasts for one to two weeks. [1] [4] [5]
Gastroenteritis by other viruses, e.g. rotavirus, calcivirus Viral gastropathies are commoner than bacterial gastroenteritis, and the clinical symptoms and signs can be difficult to differentiate. Antigen detection and PCR techniques are diagnostic methods. [1]
Cholera Caused by the comma shaped bacteria Vibrio cholerae, cholera once had a dominant prevalence all over the world, but specially in developing countries. The characteristic 'rice water diarrhea' and prolonged severe dehydration are hallmark features. It's important to exclude by blood cultures or stool cultures, because the mortality rate of cholera still remains high. [6] [7]
References
  1. ROONEY RM et al. A review of outbreaks of foodborne disease associated with passenger ships: evidence for risk management. Public Health Rep. 2004 Jul-Aug; 119(4): 427–434. doi: 10.1016/j.phr.2004.05.007
  2. SCAVIA G, STAFFOLANI M, FISICHELLA S, STRIANO G, COLLETTA S, FERRI G, ESCHER M, MINELLI F and CAPRIOLI A. Enteroaggregative Escherichia coli associated with a foodborne outbreak of gastroenteritis. J Med Microbiol. [online] 2008 Sep;57(Pt 9):1141-6. [viewed April 27, 2014] Available at doi: 10.1099/jmm.0.2008/001362-0.
  3. PAYNE CJ, PETROVIC M, ROBERTS RJ, PAUL A, LINNANE E, WALKER M, KIRBY D, BURGESS A, SMITH RM, CHEASTY T, WILLSHAW G and SALMON RL. Vero cytotoxin-producing Escherichia coli O157 gastroenteritis in farm visitors, North Wales. Emerg Infect Dis. [online] 2003 May;9(5):526-30. [viewed April 27, 2014] Available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2972679/
  4. MAJOWICZ SE, MUSTO J, SCALLAN E, ANGULO FJ, KIRK M, O'BRIEN SJ, JONES TF, FAZIL A and HOEKSTRA RM; INTERNATIONAL COLLABORATION ON ENTERIC DISEASE 'BURDEN OF ILLNESS' STUDIES. The global burden of nontyphoidal Salmonella gastroenteritis. Clin Infect Dis. [online] 2010 Mar 15;50(6):882-9. [viewed April 27, 2014] Available at doi: 10.1086/650733.
  5. BAR-MEIR M, RAVEH D, YINNON AM, BENENSON S, RUDENSKY B and SCHLESINGER Y. Non-Typhi Salmonella gastroenteritis in children presenting to the emergency department: characteristics of patients with associated bacteraemia. Clin Microbiol Infect. [online] 2005 Aug;11(8):651-5. [viewed April 27, 2014] Available at DOI: 10.1111/j.1469-0691.2005.01200.x
  6. FINKELSTEIN RA. Cholera, Vibrio cholerae O1 and O139, and Other Pathogenic Vibrios; Chapter 24, Medical Microbiology. [web] 4th edition. [viewed April 27, 2014] Available at http://www.ncbi.nlm.nih.gov/books/NBK8407/
  7. HARRIS JB, LAROCQUE RC, QADRI F, RYAN ET and CALDERWOOD SB. Cholera. Lancet. [online] 2012 Jun 30;379(9835):2466-76. [viewed April 27, 2014] Available at doi: 10.1016/S0140-6736(12)60436-X.

Investigations - for Diagnosis

Fact Explanation
Viral PCR in stools Virus shedding is present in stools 18 hours -28 days after ingestion and detectable by reverse transcription-PCR. [1] PCR can be used to identify different strains of the virus as well. [2]
Viral antigen testing by Enzyme-Linked Immunosorbent Assay. Viral antigens were detected by ELISA 33 hours after ingestion and lasted 10 days afterwards. [1] This test also can be used to identify serological strains. [3] [4]
Immunological Electron Microscopy Small round-structured virus can be visualized. [5] [6]
References
  1. ATMAR RL, OPEKUN AR, GILGER MA, ESTES MK, CRAWFORD SE, NEILL FH and GRAHAM DY. Norwalk virus shedding after experimental human infection. Emerg Infect Dis. [online] 2008 Oct;14(10):1553-7. [viewed April 26, 2014] Available at doi: 10.3201/eid1410.080117.
  2. MOE CL, GENTSCH J, ANDO T, GROHMANN G, MONROE SS, JIANG X, WANG J, ESTES MK, SETO Y, HUMPHREY C, et al. Application of PCR to detect Norwalk virus in fecal specimens from outbreaks of gastroenteritis. J Clin Microbiol. [online]1994 Mar;32(3):642-8. [viewed April 26, 2014] Available at http://www.ncbi.nlm.nih.gov/pmc/articles/pmid/8195372/
  3. SMIT TK, STEELE AD, PEENZE I, JIANG X and ESTES MK. Study of Norwalk virus and Mexico virus infections at Ga-Rankuwa Hospital, Ga-Rankuwa, South Africa. J Clin Microbiol. [online] 1997 Sep;35(9):2381-5. [viewed April 26, 2014] Available at http://www.ncbi.nlm.nih.gov/pmc/articles/pmid/9276420/
  4. ELMIRA T et al. Norovirus Transmission on Cruise Ship. Emerg Infect Dis. [online] Jan 2005; 11(1): 154–157. [viewed April 26, 2014] Available at doi: 10.3201/eid1101.040434
  5. KAPIKIAN AZ. The discovery of the 27-nm Norwalk virus: an historic perspective. J Infect Dis. [online] 2000 May;181 Suppl 2:S295-302. [viewed April 26, 2014] Available at http://jid.oxfordjournals.org/content/181/Supplement_2/S295.long
  6. LEWIS D et al. Use of solid-phase immune electron microscopy for classification of Norwalk-like viruses into six antigenic groups from 10 outbreaks of gastroenteritis in the United States. J Clin Microbiol. [online] Feb 1995; 33(2): 501–504. [viewed April 26, 2014] Available at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC227978/

Management - General Measures

Fact Explanation
Oral hydartion with ORS (Oral Rehydration Salt solution) A substantial reduction of mortality and morbidity in acute gastroenteritis has been reported after using low osmolality ORS solution. [1] It is used it two phases, a rehydration phase to replace existing losses, and a maintenance phase where replacement of ongoing fluid and electrolyte losses is done. [1] [2] The amount to be administered should be calculated according to the weight of the patient and the severity of dehydration. [1] [2] [3] [4]
Dietary management Early nutritional support has proven effective throughout the world in treating acute diarrhea.[1]
Zn supplementation Zinc supplementation can reduce the incidence and severity of diarrheal disease [3] [5] [6]
Intravenous rehydration Only in patients presenting with severe dehydration requiring hospital admission. [7]
References
  1. KING CK, GLASS R, BRESEE JS and DUGGAN C; CENTERS FOR DISEASE CONTROL AND PREVENTION. Managing acute gastroenteritis among children: oral rehydration, maintenance, and nutritional therapy. MMWR Recomm Rep. [online] 2003 Nov 21;52(RR-16):1-16. [viewed April 27, 2014] Available at http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5216a1.htm
  2. KARIMI A, and GHANAIE RM. Management of Acute Infectious Gastroenteritis in Children. Journal of Comprehensive Pediatrics. [online] 4(1): E17823. [viewed April 27, 2014] Available at http://comprped.com/?page=article&article_id=17823
  3. NIESCIERENKO M and BACHUR R. Advances in pediatric dehydration therapy. Curr Opin Pediatr. [online] 2013 Jun;25(3):304-9. [viewed April 27, 2014] Available at doi: 10.1097/MOP.0b013e328360a1bd.
  4. DUGGAN C, LASCHE J, MCCARTY M, MITCHELL K, DERSHEWITZ R, LERMAN SJ, HIGHAM M, RADZEVICH A and KLEINMAN RE. Oral rehydration solution for acute diarrhea prevents subsequent unscheduled follow-up visits. Pediatrics. [online] 1999 Sep;104(3):e29. [viewed April 27, 2014] Available at http://pediatrics.aappublications.org/content/104/3/e29.long
  5. AWASTHI S; INCLEN CHILDNET ZINC EFFECTIVENESS FOR DIARRHEA (IC-ZED) GROUP. Zinc supplementation in acute diarrhea is acceptable, does not interfere with oral rehydration, and reduces the use of other medications: a randomized trial in five countries. J Pediatr Gastroenterol Nutr. [online] 2006 Mar;42(3):300-5. [viewed April 27, 2014] Available at doi: 10.1097/01.mpg.0000189340.00516.30
  6. BHANDARI N, MAZUMDER S, TANEJA S, DUBE B, AGARWAL RC, MAHALANABIS D, FONTAINE O, BLACK RE and BHAN MK. Effectiveness of zinc supplementation plus oral rehydration salts compared with oral rehydration salts alone as a treatment for acute diarrhea in a primary care setting: a cluster randomized trial. Pediatrics. [online] 2008 May;121(5):e1279-85. [viewed April 27, 2014] Available at doi: 10.1542/peds.2007-1939.
  7. NAGER AL and WANG VJ. Comparison of nasogastric and intravenous methods of rehydration in pediatric patients with acute dehydration. Pediatrics. [online] 2002 Apr;109(4):566-72. [viewed April 27, 2014] Available at doi: 10.1542/peds.109.4.566