Epidemiology and Management of Diarrheal Diseases

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Epidemiology and Management of Diarrheal Diseases

• Amal Mitra, MD, MPH, DrPH
• Professor
• University of Southern Mississippi
• Readings Diarrhoeal Diseases

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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

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TYPES OF DIARRHEA
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COMMON CAUSES OF DIARRHEA- BACTERIA

• Vibrio cholera
• Shigella
• Escherichia coli
• Salmonella
• Campylobacter jejuni
• Yersinia enterocolitica
• Staphylococcus
• Vibrio parahemolyticus
• Clostridium difficile

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COMMON CAUSES OF DIARRHEA- VIRUS

• Rotavirus
• Adenoviruses
• Caliciviruses
• Astroviruses
• Norwalk agents and Norwalk-like viruses

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COMMON CAUSES OF DIARRHEA- PARASITE

• Entameba histolytica
• Giardia lamblia
• Cryptosporidium
• Isospora

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COMMON CAUSES OF DIARRHEA-OTHERS

• Metabolic disease
• Hyperthyroidism
• Diabetes mellitus
• Pancreatic insufficiency
• Food allergy
• Lactose intolerance
• Antibiotics
• Irritable bowel syndrome

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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

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SEASONALITY
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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

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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

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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/vo
  l9no7/02-0760.htm

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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/fact
  sheets/HGIC3663.htm

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TYPES OF SHIGELLA

• The major serotypes of Shigella that cause
  diarrhea are
• Dysenteriae type 1 or Shigella shiga
• Shigella flexneri
• Shigella sonnei
• Shigella boydii

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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 O157H7)
• Enteroaggregative E. coli (EAggEC)
• Diffuse adherent E. coli (DAEC)

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CLINICAL FEATURE CHOLERA

• Rice-watery stool
• Marked dehydration
• Projectile vomiting
• No fever or abdominal pain
• Muscle cramps
• Hypovolemic shock
• Scanty urine

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CLINICAL FEATURE E. COLI DIARRHEA

• Watery stools
• Vomiting is common
• Dehydration moderate to severe
• Fever often of moderate grade
• Mild abdominal pain

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CLINICAL FEATUREROTAVIRUS 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

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CLINICAL FEATURESHIGELLOSIS

• 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

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CLINICAL FEATUREAMEBIASIS

• Offensive and bulky stools containing mostly
  mucus and sometimes blood
• Lower abdominal cramp
• Mild grade fever
• No dehydration

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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

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ASSESSMENT OF DEHYDRATION
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ASSESSMENT OF DEHYDRATION (contd.)
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ASSESSMENT OF DEHYDRATION (contd.)
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TREATMENT

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

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COMPOSITION OF ORS
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AMOUNT OF SALT LOSS DURING DIARRHEA
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ANTIMICROBIAL AGENTS
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COMPLICATIONSWATERY DIARRHEA

• Dehydration
• Electrolyte imbalances
• Tetany
• Convulsions
• Hypoglycemia
• Renal failure

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COMPLICATIONSDYSENTERY

• Electrolyte imbalances
• Convulsions
• Hemolytic uremic syndrome (HUS)
• Leukemoid reaction
• Toxic megacolon
• Protein losing enteropathy
• Arthritis
• Perforation

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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.

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PREVENTION

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