Epidemiology and Management of Diarrheal Diseases

1. Epidemiology and Management of Diarrheal Diseases Amal Mitra, MD, MPH, DrPH Professor University of Southern Mississippi Readings: Diarrhoeal Diseases

2. DEFINITION • Watery Diarrhea: 3 or more liquid or watery stools in 24 h • Dysentery: Presence of blood and/or mucus in stools • Persistent Diarrhea: Diarrhea lasting for 14 days or more

3. TYPES OF DIARRHEA

4. COMMON CAUSES OF DIARRHEA- BACTERIA • Vibrio cholera • Shigella • Escherichia coli • Salmonella • Campylobacter jejuni • Yersinia enterocolitica • Staphylococcus • Vibrio parahemolyticus • Clostridium difficile

5. COMMON CAUSES OF DIARRHEA- VIRUS • Rotavirus • Adenoviruses • Caliciviruses • Astroviruses • Norwalk agents and Norwalk-like viruses

6. COMMON CAUSES OF DIARRHEA- PARASITE • Entameba histolytica • Giardia lamblia • Cryptosporidium • Isospora

7. COMMON CAUSES OF DIARRHEA-OTHERS • Metabolic disease • Hyperthyroidism • Diabetes mellitus • Pancreatic insufficiency • Food allergy • Lactose intolerance • Antibiotics • Irritable bowel syndrome

8. TRANSMISSION • Most of the diarrheal agents are transmitted by the fecal-oral route • Some viruses (such as rotavirus) can be transmitted through air • Nosocommial transmission is possible • Shigella (the bacteria causing dysentery) is mainly transmitted person-to-person

9. SEASONALITY

10. PERSON-AT-RISK • Cholera: 2 years and above, uncommon in very young infants • Shigellosis: more common in young children aged below 5 years • Rotavirus diarrhea: more common in young infants and children aged 1-2 years • E. coli diarrhea: can occur at any age • Amebiasis: more common among adults

11. TYPES OF VIBRIO CHOLERA • Two major biotypes of Vibrio cholera that cause diarrhea are: • Classical • ElTor • Two common serotypes of Vibrio cholera that cause diarrhea are: • Inaba • Ogawa

12. Vibrio cholerae O139 • Vibrio cholerae in O-group 139 was first isolated in 1992 and by 1993 had been found throughout the Indian subcontinent. This epidemic expansion probably resulted from a single source after a lateral gene transfer (LGT) event that changed the serotype of an epidemic V. cholerae O1 El Tor strain to O139. • More information: http://www.cdc.gov/ncidod/EID/vol9no7/02-0760.htm

13. Vibrio vulnificus • The organism Vibrio vulnificus causes wound infections, gastroenteritis or a serious syndrome known as "primary septicema."  • V. vulnificus infections are either transmitted to humans through open wounds in contact with seawater or through consumption of certain improperly cooked or raw shellfish. • This bacterium has been isolated from water, sediment, plankton and shellfish (oysters, clams and crabs) located in the Gulf of Mexico, the Atlantic Coast as far north as Cape Cod and the entire U.S. West Coast.  • Cases of illness have also been associated with brackish lakes in New Mexico and Oklahoma. • For more information: http://hgic.clemson.edu/factsheets/HGIC3663.htm

14. TYPES OF SHIGELLA • The major serotypes of Shigella that cause diarrhea are: • Dysenteriae type 1 or Shigella shiga • Shigella flexneri • Shigella sonnei • Shigella boydii

15. TYPES OF E. COLI • Six major types of Escherichia coli cause diarrhea: • Enterotoxigenic E. coli (ETEC) • Enteroinvasive E. coli (EIEC) • Enteropathogenic E. coli (EPEC) • Enterohemorrhagic E. coli (E. coli O157:H7) • Enteroaggregative E. coli (EAggEC) • Diffuse adherent E. coli (DAEC)

16. CLINICAL FEATURE: CHOLERA • Rice-watery stool • Marked dehydration • Projectile vomiting • No fever or abdominal pain • Muscle cramps • Hypovolemic shock • Scanty urine

17. CLINICAL FEATURE: E. COLI DIARRHEA • Watery stools • Vomiting is common • Dehydration moderate to severe • Fever– often of moderate grade • Mild abdominal pain

18. CLINICAL FEATURE:ROTAVIRUS DIARRHEA • Insidious onset • Prodromal symptoms, including fever, cough, and vomiting precede diarrhea • Stools are watery or semi-liquid; the color is greenish or yellowish– typically looks like yoghurt mixed in water • Mild to moderate dehydration • Fever– moderate grade

19. CLINICAL FEATURE:SHIGELLOSIS • Frequent passage of scanty amount of stools, mostly mixed with blood and mucus • Moderate to high grade fever • Severe abdominal cramps • Tenesmus– pain around anus during defecation • Usually no dehydration

20. CLINICAL FEATURE:AMEBIASIS • Offensive and bulky stools containing mostly mucus and sometimes blood • Lower abdominal cramp • Mild grade fever • No dehydration

21. LABORATORY DIAGNOSIS • Stool microscopy • Dark field microscopy of stool for cholera • Stool cultures • ELISA for rotavirus • Immunoassays, bioassays or DNA probe tests to identify E. coli strains

22. ASSESSMENT OF DEHYDRATION

23. ASSESSMENT OF DEHYDRATION (contd.)

24. ASSESSMENT OF DEHYDRATION (contd.)

25. TREATMENT • Rehydration– replace the loss of fluid and electrolytes • Antibiotics– according to the type of pathogens • Start food as soon as possible

26. COMPOSITION OF ORS

27. AMOUNT OF SALT LOSS DURING DIARRHEA

28. ANTIMICROBIAL AGENTS

29. COMPLICATIONS:WATERY DIARRHEA • Dehydration • Electrolyte imbalances • Tetany • Convulsions • Hypoglycemia • Renal failure

30. COMPLICATIONS:DYSENTERY • Electrolyte imbalances • Convulsions • Hemolytic uremic syndrome (HUS) • Leukemoid reaction • Toxic megacolon • Protein losing enteropathy • Arthritis • Perforation

31. VACCINES • An oral cholera vaccine is available, which gives immunity to 50-60% of those who take the vaccine, and this immunity lasts only a few months. • No vaccines are available against shigellosis • A vaccine against rotavirus diarrhea has been withdrawn recently from the market.

32. PREVENTION • Safe drinking water and food “Boil it, cook it, peel it, or forget it. " • Hand washing • Proper sanitation