Epidemiology of intestinal diseases

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Epidemiology of intestinal diseases

• Jana Dánová
• Dept.of Epidemiology

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ETIOLOGIC AGENT OF ENTERIC INFECTIONS

• Bacteria
• The most frequent group of agent
• Viruses
• Rotavirus, Norovirus etc.
• Protozoa
• Ent.histolytica, Lamblia intestinalis etc.
• Metazoa Worms
• Taenia, Ascaris, Enterobius

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INFECTIOUS AGENT OF GASTROINTESTINAL DISEASES

• Bacterial
• Salmonella Typhi, Salmonella Paratyphi (A, B, C)
• Salmonella Enteritidis, Salmonella Typhimurium
  and more than 2000 serotypes
• Shigella sonei, S. flexneri, S.boydi, S.
  dysenteriae
• Campylobacter jejuni, Campylobacter coli
• Escherichia coli (ETEC, EPEC, EIEC, EHEC)
• Yersinia enterocolitica
• Vibrio cholerae
• Enterotoxicosis
• Clostridium botulinum, Clostridium perfringens A,
  Clostridium difficile,
• Staphylococcus aureus, Vibrio parahemolyticus,
  Bacilus cereus
• Viral
• Rotavirus, Norovirus, Astrovirus, Adenovirus
• Parasital- protozoal
• Entamoeba histolytica, Giardia intestinalis,
  Cryptosporidium parvum,
• Taenia saginata, Taenia solium

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Routes of transmission of agents causing
diarrhoea

• The infectious agents are usually spread by
  the faecal-oral route, which includes the
  ingestion of faecally contaminated water or food,
  
• person-to-person transmission
• direct contact with infected faeces

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THREE TYPES OF DIARRHOEA

• Diarrhoea is usually defined as the passage of
  three or more loose or watery stools in a 24-hour
  period
• Three clinical syndromes of diarrhoea have been
  defined, reflecting a different pathogenesis
• A c u t e W a t e r y D i a r r h o e a
• D y s e n t r y
• P e r s i s t e n t D i a r r h o e a

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A c u t e W a t e r y D i a r r h o e a

• Begins acutely, lasts less than 14 days and
  involves the passage of frequent loose or watery
  stools without visible blood. Vomiting may occur
  and fever may be present. It causes serious
  dehydration and contributes to undernutrition..
  The most important etiologic agents are
• Enterotoxigenic Escherichia coli
• Shigella
• Campylobacter jejuni
• Vibrio cholerae 01
• Salmonella
• Enteropathogenic E. coli

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D y s e n t r y

• The term dysentry refers to diarrhoea with
• visible blood in the faeces. Important effects
  
• of dysentry include anorexia, rapid weight
  loss
• and damage of the intestinal mucosa.
• The most important cause of acute dysentry are
• Shigella
• Campylobacter jejuni
• Salmonella
• Entamoeba histolytica can cause serious dysentry
  in young adults.

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P e r s i s t e n t D i a r r h o e a

• This term refers to acute diarrhoea of
• unusually long duration
• (at least 14 days). It may begin either as
  watery diarrhoea or as dysentry
• Marked weight loss is frequent,
• risk of dehydration is high
• There is no single microbial cause of PD,
  enteroadherent E. coli and Cryptosporidia may
  play a greater role than other agents.
•  

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TYPHOID FEVER

• Etiol. agent Salmonella typhi (resistant to
  external
• factors)
• Clinical symptoms systemic disease, fever,
  headache, weekness, anorexia, roseola,
  bradycardia, splenomegaly
• Mode of transmission direct- in families and
  group of
• 
  people(carriers)
• Indirect
  due to contaminated
• 
  vehicle (explosive epidemic)
• Incubation period 7 21 days
• (can vary - 3 days and 3
  month)

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DG. OF TYPHOID FEVER

• Clinical from clinical symptoms
• Laboratory cultivation S.typhi blood, faeces,
  urine
• Epidemiological contact with carriers

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PARATYPHOID FEVER

• Etiol.agent Salmonella paratyphi A, B, C (B most
  frequent)
• Climical symptoms similar clinical picture as
  typhoid fever, but milder and case-fatality is
  lower
• Mode of transmission as typhoid fever
• Incubation period 1 10 days
• Reservoir humans, rarely domestic animals

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SALMONELLOSIS

• Etiol.agent more than 2000 serotypes of
  Salmonella
• most frequent S.Enteritidis,
  S.Typhimurium, S.Agona
• Clinical symptoms acute diarrhoeal disease
  (enterocolitis), with nausea,vomiting
• Mode of transmission indirect eating of food
  with
• salmonella (milk, eggs, meat etc.),
  secondary
• contamination of raw fruits and
  vegetables,
• multiplication
• direct
  fecal-oral transmision
• Incubation period 6 72 hours

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SHIGELLOSIS

• Etiol.agent Shigella sonnei up to 75
• Shigella flexneri - 22
• Shigella boydii 3
• Shigella dysenteriae no
  incidence in CR
• Clinical symptoms acute diarrhoeal disease with
  fever,
• tenesmus, vomiting, up to 20
  stools daily
• Mode of transmission direct fecal-oral
  transmission
• indirect
  vehiculum (water, food)
• Incubation period 1 7 days

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CAMPYLOBACTERIOSIS

• Etiol.agent Campylobacter jejuni
• less common - Campylobacter
  coli
• Clinical symptoms acute diarrhoeal disease,
  fever,
• nausea,vomiting, many infections are
  asymptomatic
• Mode of transmission mostly ingestion of the
  organisms in undercooked chicken and pork,
  contaminated water, milk, contact with
  infected pets
• Incubation period 2 5 days

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CHOLERA

• Etiol.agent Vibrio cholerae 2 biotypes
• clasical El Tor
• Clinical symptoms acute diarrhoeal disease,
  fever,
• nausea,vomiting, diarhoea caused by
  cholera toxin,
• secretion of watter and electrolyted
  in small bowel
• Mode of transmission mostly indirect -
  contaminated
• 
  water, food
• direct
  poor conditions
• Incubation period 2-3 days

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ALIMENTARY INTOXICATION

• Staphylococcus
• Staphylococcus aureus
• Enterobacteriacae
• E.coli, Citrobacter
• Aerobic sporulates
• Bacilus cereus
• Anaerobic sporulates
• Clostridium botulinum
• Clostridium perfringens A
• Clostridium difficile

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ROTAVIRUS DISEASE

• Etiol.agent Rotavirus (belongs to Reoviridae)
• Groups A, B, C, D, E (most
  freq. A)
• Climical symptoms sporadic, seasonal often
  severe
• gastroenteritis (infants, small
  children, )
• watery diarrhea, vomiting, fever,
  dehydration
• Mode of transmission fecal-oral transmission,
  possible
• respiratory spread
• Incubation period 24 72 hours
• Reservoir humans (animal viruses not spread to
  people)

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Rotavirus

• Discovered in 1973
• Worldwide distribution
• All children exposed by age 4-5
• Double stranded RNA virus
• Several groups (A-E vs G-P)
• Most common cause of viral diarrhea
• 35 hospitalized, 10 community

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Rotavirus
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Transmission of Rotavirus

• Contaminated water supplies
• Poor hygiene
• Food
• Fecal-oral
• Fomites

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Rotavirus Clinical Syndromes

• Childhood gastroenteritis
• Endemic in tropics
• Winter in temperate zone
• Outbreaks
• Day care centers
• Hospitals
• Immunocompromised adults

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How does Rotavirus cause diarrhea?

• Injures intestinal epithelium
• Malabsorption
• Increases secretion by epithelium

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Rotavirus Clinical Syndromes

• Asymptomatic carriers
• Diarrheal illness
• 2-3 day incubation period
• diarrhea, vomiting fever 3-7 days
• high infectivity

• Complications
• dehydration
• chronic diarrhea
• dissemination
• NEC

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NOROVIRUS DISEASE

• Etiol.agent Norovirus (RNA virus)
• Clinical symptoms nausea, vomitting, diarrhea,
  occurs in outbreaks
• Mode of transmission fecal-oral route, airborne,
  foodborne, waterborne
• Incubation period 24 48 hours
• Reservoir people are the only known reservoir

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PREVENTIVE MEASURES

• 1. health education
• 2. preventive examination
• 3. a suitable technology of the food preparation
• 4. prevent a secondary contamination
• 5. exclusion of noxious food stuffs

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PROTECTION AGAINST EPIDEMIC

• 1. boiling and preparation of food
• 2. protection of water supplies
• 3. isolation of patient
• 4. active search for positives
• 5. bacteriological follow-up of the positives
• 6. continuous and complete disinfection of the
  focus

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METHODS OF CONTROL

• 1. elimination of the infectious source
• 2. examination in the focus of infection
• 3. report to the hygienic-epidemiological service
• 4. making the exact diagnosis
• 5. isolation of the sick (screening)
• 6. adequate treatment with stress on rehydratation