1. ACUTE GASTROENTERITIS
Symptoms:
@ Vomiting and watery diarrhea
@ Fever (38.5°C) and dehydration.
Causes of gastroenteritis:
Bacterial:
@ Salmonella spp.
@ Enteropathogenic E. coli
@ Camp. jejuni
@ Shigella spp.
@ Vibrio spp.

3. Viral:
@ Rotaviruses: commonest in children
@ Enteric adenoviruses (types 40 & 41)
@ Astroviruses (star-like in morphology)
@ Norwalk virus

5. Lab. Diagnosis of Gastroenteritis:
Viral:
@ Stool electron microscopy.
@ PCR to determine the viral genome.
@ ELISA to detect viral antigens in stool
@ Latex agglutination for viral antigens
Bacterial:
@ Microscopy
@ Stool culture
@ Biochemical reactions
@ Serological typing.

7. Norwalk Virus
@ Discovered its association with a
gastroenteritis in Norwalk (USA)
@ Causes gastroenteritis in all ages.
@ Spread is by eating shellfish and water
@ Aerosols of forced vomiting increase
transmission

9. Rotavirus Gastroenteritis
Presentation:
@ Vomiting, watery diarrhea
Lab. Diagnosis:
@ Electron microscopy to detect rotavirus
@ Rotavirus will not grow in tissue culture
@ PCR to determine the viral genome.
@ ELISA detection of antigens in stool
@ Detection of viral antigens by latex
agglutination.

11. FOOD POISONING
Symptoms:
@ Nausea, diarrhea
@ Abdominal pain, cramps
Provisional Diagnosis:
@ If any member of family have had
similar symptoms.
@ If patient ate anything that might
cause the illness.
@ If patient had a meal in a party.

13. Aetiology of Bacterial Food Poisoning
Divided according to formation of toxin:
Preformed toxin:
@ Formed in the food before ingestion
(gives more vomiting), associated with:
# Bacillus cereus
# S. Aureus
# Cl. Botulinum

15. Toxin production in vivo:
@ Due to multiplication of the organism
and production of toxin inside the body
(gives more diarrhea), associated with:
# Cl. Perfringens
# Bacillus cereus
# Enterotoxigenic E. coli
# Vibrio spp.

17. Tissue invasion:
@ Associated with:
# Camp. jejuni
# Salmonella spp.
# Enteroinvasive E. coli
Other Causes of Food Poisoning:
@ Norwalk virus.
@ Heavy metals

19. Food Varieties causing Food Poisoning
@ Clostridium perfringens :
Contaminated meat, meat soup.
@ Staph. aureus:
Contaminated poultry, eggs, mayonnaise
@ Bacillus cereus:
Contaminated cooked rice.
@ Salmonella:
Contaminated poultry, raw eggs.

21. @ Campylobacter jejuni:
Contaminated milk, poultry.
@ Norwalk virus:
Contaminated shellfish.
Prevention of Food Poisoning:
@ Consuming pasteurized milk
@ Selecting healthy hens
@ Consuming well-cooked meat and rice
@ Adequate cooking of eggs, poultry, fish

23. Lab. Diagnosis of Food Poisoning:
@ Vomitus microscopy & culture: useless
@ Stool culture and food ruminants for:
Salmonella, Vibrio, Campylobacter,
S. aureus, E. coli, Cl. perfringens
@ Norwalk virus is diagnosed by:
Electron microscopy, PCR, ELISA,
Rapid latex particle agglutination.
@ Epidemiological investigations of food
poisoning outbreaks.

25. Salmonella Food Poisoning
@ Due to Sal. enteriditis, Sal. dublin,
Sal. typhimurium, Sal. agona.
@ Most of these are from animal sources
@ S. enteriditis type 4 causes food
poisoning due to contaminated eggs.
@ Salmonella food poisoning is mild, and
self-limiting
@ But it can cause neonatal meningitis
and septicaemia.