Lecture 23: Diarrhoea and acute gastrointestinal illness Flashcards
Signs and symptoms AGI
- Vomiting
- Diarrhoea: Acute, watery, bloody(dysentery), severe (6 x a day)
- Abdo pain and cramping
- Fever
Causes of AGI? differences between them:
Onset; diarrhoea; vomiting; fever/pain; rehydration; antibiotics
Virus: Faster(hrs/days); probably; YES; fever, likely pain; yes; no
Bacteria: range; yes; probaby; abdo pain; yes; sometimes
Protozoa: slower; yes; possibly; abdo pain; yes; prob
Viral AGI
- Small intestine
- Norovirus (+ve strand ssRNA) , Rotavirus (dsRNA)
- Self limiting generally, over in 48 hours
- Effective vaccines for rotavirus
Ways Bacteria cause AGI?
Colonisation of intestines and toxin production
Invasion of intestinal tissue
Toxin produced in food but not ingested, food poisoning
Bacterial agents that colonise and invade intestinal tissue
Campylobacter jejuni
non typhoid salmonella
yersinia enterocolitica
enteroinvasive E coli
May cause blood in faeces, abdo cramping
What is injestion of bacterial toxins?
- No infection. Food poisoning.
- Staph aureus
- Clostridium perfringens
- Bacillus cereus
- Vomiting withing 2-7 hours, symptoms cleared 1-2 days
Protozoa information
_____ and ______
______ contaminated by human faeces e.g _____ _______
incubation of 1 week
symptoms 4-6 weeks
diarrhoea, flatulence, foul stools
mostly self limiting, giardia might need _______
Giardia and Cryptosporidium
food/water contaminated by human faeces e.g farmer, tramper, pet owner
incubation of 1 week
symptoms 4-6 weeks
diarrhoea, flatulence, foul stools
mostly self limiting, giardia might need metronidazole
New Zealand most common agenst of AGI
Worldwide AGI
Campylobacter, Salmonella, Giardia
Most serious, listeria
Diarrhoeal disease really bad, a lot of cholera. Mostly children. E coli, cholera, norovirus an rotavirus
NZ outbreaks (2 or more cases with common source)
Norovirus
Sources of AGI
- Human/animal GI -tract/faeces: Faceal oral route direct or indirect
- Animals, infected people and carriers
- Contaminated food and water
Contaminated food route
means to stop
Animal faces- contaminated carcass(can eat these) and fertilised vegetables
These become food items, which we eat and causes the AGI.
Human Faeces can then be transferred to food product
Slaughter, farming practice, cooking, storage, hygiene
AGI risk factors
Consume retail food; consme at risk foods (soft cheese listeria); farm animal contact; consume untreated water; faecal matter contact; symptomatic people contact; recreational water; sick animals; overseas travel within incubation period
Contaminated water route
means to stop
Human and animal faeces contaminate water source
Drinking and irrigation water into our food and drink
AGI
Farming and sewerage, supply, more sewerage
Stool culture types
note food worker would have 3 negative tests to see if clear
- Sheep blood: grow most pathogens, including listeria that won’t grow elsewhere
- MacConkey agar with lactose: E coli will ferment lactose, Salmonella, Shigella, yersinia do not
- Maconkey agar with sorbitol: most E coli ferment sorbitol, STEC do not
- XLD: slamonella and shigella grow
- Campy plate: campylobacter
Antibody or PCR for viral
Antigen test for protozoa
AGI complications
Dehydration, bactaraemia (salmonella, campylobacter); haemolytic uremic syndrome (STEC on kidney); Guillan barre and campylobacter; reactive arthritis campy, yersinia
