Case 5 Flashcards
Foodborne disease
caused by consuming food contaminated by bacteria and/or their toxins, parasites, viruses, chemicals, or other agents (US FDA).
- Infections are the microorganism infecting and intoxication is the microorganism leading to toxins. Food poisoning would be the contamination of food with chemical toxins or microorganisms. Bacteria, Fungi, Virus, protozoa are all examples of microorganisms.
Infection
Viable microorganism are ingested → multiply in human body
Intoxication
Microbial/naturally occurring toxins are consumed in contaminated foods
Bacteria
- Gram+ or Gram-
- Different shapes
- Mechanisms of action: Infection & intoxication
- Names: E.coli
Salmonella
Campylobacter
Clostridia
Virus
- Generally enteric, transmitted by the faecal-oral route.
- Transmission by person-to-person contact and via contaminated water is common
- Mechanisms of action: Infection
- Names: Hepatitis A
Norovirus
Prions
- Prions are misfolded proteins with the ability to transmit their misfolded shape onto normal variants of the same protein.
- Prion diseases can affect both humans and animals and are sometimes spread to humans by infected meat products.
- Mechanisms of action: Infection
- Names: Bovine
spongiform
encephalitis (BSE)
Fungi
- Secondary metabolites of moulds that can induce acute and chronic symptoms: Carcinogenic, mutagenic, and estrogenic effects in humans and animals
- Principle fungi: Aspergillus, Penicillium, Fusarium
- Mechanisms of action: Intoxication
- Names: Mycotoxins
Aflatoxins
Ochratoxins
Protozoa
- Unicellular organisms that colonise the intestinal epithelium and form cysts
- May survive for long periods in the environment
- Mechanisms of action: Infection
- Names: Giardia intestinalis
Entamoeba
Toxoplasma gondii
Cyclospora cayetanensis
Cryptosporidium parvum
Parasites
- Organisms that live off other living organisms (hosts)
- Transmitted from animals to humans, from humans to humans, or from humans to animals
- Infective stages of parasites are eaten in raw or partially cooked protein foods, or in raw veggies and fruits inadequately washed → Live and reproduce within tissues and organs of infected human and animal hosts, often excreted in feces
- Complex life cycles involving 1-2 intermediate hosts
- Classified as:
• Helminths (multicellular worms): Trematodes, nematodes, cestodes
• Protozoa (Single-celled microscopic organisms): Cryptosposridia and Cyclospora
Helminthes
- Helminthiasis, also known as worm infection, is any macroparasitic disease of humans and other animals in which a part of the body is infected with parasitic worms, known as helminths
- Names: Trichinella
Hepatitis A virus
- One of the more severe foodborne disease
- immune destruction of liver cells
- virus can be shed in feces for up to 14 days before onset of illness -> possible for infected food handle with poor personal hygiene to contaminate food (virus may be shed in feces for 1-2 weeks after onset of symptoms)
- foods contaminated by infected persons or fecally contaminated water
- most heat enteric than most of enteric viruses + resistant to drying
Norovirus
- First enteric virus reported to be foodborne
- Difficult to detect, especially from foods
- Transmission :
• Contact with infected individuals or fecally contaminated water/materials
• Shellfish: Frequently contaminated with human feces from sewage discharges
• Aerosolization of vomitus-containing virus particles
Astrovirus
- Small, round viruses that have surface projections resembling a five or six-pointed star
- Incubation longer than norovirus (3-4 days), duration of illness is longer (7-14 days), vomiting is less common
- Predominant symptom: Diarrhea
Rotavirus
- Single most important cause of infantile gastroenteritis worldwide
- Rotavirus genome consists of 11 segments of double-stranded RNA surrounded by a double-shelled viral capsid
- Incubation: 1-3 days
- Illness characterised by fever, vomiting, and diarrhea
- Long-term effect: hepatitis A, distraction of liver cells
Trematode
- Involve 2 intermediate hosts
- Infection takes place through consumption of raw, undercooked, underprocessed freshwater fish or crustaceans containing infective stages of these parasites
- Diseases caused by foodborne trematodes: Cholangiocarcinoma, gallstones, severe liver disease, gastrointestinal problems
Nematode
- Usual foods involved: Undercooked or raw fishery products
- Most common species: Anisakis simplex
- Commonly present in fish caught in the wild, most frequently in the liver and belly cavity, can also occur in the flesh
- Trichinella spiralis:
• Cause of trichinosis in humans
• Results from consumption of contaminated raw or undercooked pork or pork products
Salmonella
Source: meat, eggs, poultry, raw milk, water, sprouts
Symptoms: nausea, abdominal cramps, diarrhea, fever, headache
Second most often reported zoonotic disease in humans
Statistically significant decreasing trend in notification rate in the EU
Campylobacteriosis
Source: raw poultry, meat, unpasteurized milk, untreated water, chicken
Symptoms: abdominal cramps, blood stool, gastroenteritis, vomiting; long-term: growth-development disturbances, neurological disorders, kidney failure
Most common reported gastrointestinal bacterial pathogen in humans
Number of notified cases decreased with 5.0% compared to 2007
Campylobacter commonly detected from live poultry, pigs and cattle
BSE (Bovine spongiform encephalopathy)
Source: infected cow meat (special parts of the cow)
Symptoms: brain-wasting, fatal within 6 months, involuntary movements, immobility, death
Listeriosis
Source: fish, cheese, meat, sandwiches, ready-to-eat-food Symptoms: flu-like, sepsis, meningitis, death
Cases decreased by 11.1% since 2007
High fatality rate20.5%