26. Characteristics, types, occurrence and prevention of enteric infections

Gastrointestinal infections

• Caused by viruses, bacteria, protozoa and helminths
• Symptoms can be caused by the organisms themselves or by toxins they produce
• If small intestine is affected:
  • Watery diarrhoea
  • Abdominal cramps
  • Vomiting
• If large intestine is affected
  • Bloody diarrhoea
  • Lower abdominal pain
  • Fever
• Infection acquired from contaminated food or drinking water, or from person-to-person as a result of poor hygiene

Diarrhoeal disease

• Epidemiology
  • Diarrhoeal disease is the second leading cause of death in children under five
  • Kills 500 000 children yearly
  • Very common in developing countries
• Causes
  • Non-inflammatory diarrhoea
    • Norovirus
    • Rotavirus
    • Food intoxication
      • S. aureus
      • B. cereus
      • C. perfringens
    • Foodborne infection
      • ETEC
      • Vibrio cholerae
    • Protozoal
      • Giardia lamblia
      • Cryptosporidum
  • Inflammatory diarrhoea
    • EHEC
    • EIEC
    • Clostridium difficile
    • Shigella
    • Salmonella
    • Campylobacter
    • Yersinia enterocolitica
    • Entamoeba histolytica
• Prevention
  • Exclusive breastfeeding
  • Vaccines
  • Clean water
  • Correct food handling
  • Hygiene
• Treatment:
  • Clean water
  • Salt
  • Sugar
  • Zinc tablets
• Risk factors
  • Children
  • Elderly
  • Pregnant
  • Malnutrition
  • Immunosuppression
  • Working with infected people
• Socioeconomic risk factors
  • Poverty
  • Overcrowding
  • Poor sanitation
  • Water contamination
  • Poor food hygiene

Types of foodborne illness

• Intoxication
  • Ingestion of a toxin which causes the illness
  • S. aureus
  • B. cereus
• Toxico-infection
  • Ingestion of a microorganism which produces toxin in the human body
  • The toxin causes the illness
  • Clostridium perfringens
  • Clostridium botulinum
• Infection
  • Ingestion of a microorganism which itself causes illness
  • Salmonella
  • Shigella
  • Hepatitis A
  • Enteric parasites
    • Trichinella
    • Taenia

Prevention of foodborne illness

• Most foodborne illness is caused by food being improperly prepared or handled at home
• Sick people should not handle food
• Vegetables and fruits should be rinsed under water
• Five keys to safer foods
  • Keep hands, surfaces and equipment clean. Wash hands before handling food
  • Separate raw and cooked foods – don’t use same equipment for both
  • Cook thoroughly – especially meat, eggs and seafood
  • Keep food at safe temperatures
    • Don’t leave cooked food in room temperature for more than 2 hours
    • Refrigerate cooked food as soon as possible
    • Do not store food too long
    • Do not thaw frozen food at room temperature, rather in the fridge
  • Use safe water and raw materials