Food-Borne Zoonosis

Question 1

What is the WHO definition of zoonosis?

Answer 1

Diseases and infections naturally transmitted between animals and humans

Question 2

What is the definition of a ‘food-borne’ disease?

Answer 2

acute illnesses associated with the recent consumption of food

Question 3

What is the definition of a foodborne infection?

Answer 3

where a disease is caused by an infection (e.g salmonella/ campylobacter)

Question 4

What is the definition of foodborne intoxication?

Answer 4

Disease resulting from a toxin (usually bacterial e.g staphylococcus)

Question 5

What are some examples of bacterial foodborne infections?

Answer 5

salmonelliosis, typhoid fever, cholera, campylobacter,

Question 6

What are some examples of viral foodborne infections?

Answer 6

hepatitis A, norwalk infection, poliomyelitis virus

Question 7

What are some examples of mycotic foodborne infections?

Answer 7

candida, sporothrix

Question 8

What are some examples of parasitic foodborne infections?

Answer 8

protozoa, roundworms, tapeworms

Question 9

What are the two species of salmonella?

Answer 9

• Salmonella bongori
• Salmonella enterica

Question 10

How many subspecies is s.enterica split into?

Answer 10

2500

Question 11

What salmonella species is the most common cause of human infection?

Answer 11

S.enteriditis

Question 12

What are the symptoms of salmonella enteriditis?

Answer 12

Acute onset fever, diarrhoea, abdominal pain, nausea

Question 13

What can prolonged salmonella symptoms lead to?

Answer 13

dehydration

Question 14

What kills salmonella in the environment?

Answer 14

• Killed by temperatures attained in commercial pasteurisation
• they are **not ** destroyed by carcasses or offal kept in freezing temperatures

Question 15

What are the two campylobacter species of public health importance?

Answer 15

• campylobacter jejuni
• campylobacter coli

Question 16

What is the campylobacter reservoir?

Answer 16

Intestinal tract of wild/domesticated birds and mammals

Question 17

What is the incubation period of campylobacter?

Answer 17

2-5 days

Question 18

What are the symptoms of campylobacter?

Answer 18

watery or bloody diarrhoea, abdominal pain, fever, headache and nausea

Question 19

What is the public health significance of human campylobacteriosis?

Answer 19

• causes painful diarrhoea
• invasive in over 65’s
• most common cause of bacterial gastroenteritis
• can also cause neuropathological conditions

Question 20

What is the shape of the listeria pathogen?

Answer 20

Gram positive rod-shaped pathogen

Question 21

What species of listeria causes almost all human cases of listeriosis?

Answer 21

Listeria monocytogenes

Question 22

What is the reservoir of listeria monocytogenes?

Answer 22

Plant matter and soil

Question 23

What is listeria monocytogenes associated with?

Answer 23

cooked meat, pate, soft cheese, smoked fish,

Question 24

What is the incubation period of listeria monocytogenes?

Answer 24

mild-flu to diarrhoea to abortion/ life threatening diseases

Question 25

What is the fatality rate of listeria in the EU?

Answer 25

12.7%

Question 26

What are most human E.Coli cases linked to?

Answer 26

poorly cooked beef, cross-contamination from raw meats,

Question 27

What is one of the benefits of E.Coli being in the normal gut flora?

Answer 27

Vitamin K synthesis

Question 28

What are the 5 groups that E.Coli strains fall into?

Answer 28

1. Enteropathogenic E. coli (EPEC) 2. Enterotoxigenic E. coli (ETEC) 3. Enteroinvasive E. coli (EIEC) 4. Enterohemorrhagic E. coli (EHEC) 5. Enteroaggregative E.coli (EAEC)

Question 29

Summarise Enteroinvasive E.coli

Answer 29

* characterised by watery diarrhoea in most patients * fever, nausea and abdominal cramps * bloody diarrhoea in less than 10% of patients * illness is usually self-limiting * high dose is required to cause infection

Question 30

Summarise enterohaemorragic e.coli

Answer 30

* caused by escheria coli serotype 0157:H7 * causes haemorrhagic colitis * characterised by bloody diarrhoea, abdominal pain that can then induce vomiting * has an incubation period of 3-4 days * death occurs in patients that develop hemolytic uremic syndrome

Question 31

What does yersinia enterolitica cause?

Answer 31

Food borne yersiniosis

Question 32

What are the four species of shigella that cause human dysentry?

Answer 32

flexneri, boydii, sonnei, dysentriae

Question 33

How is shigella transmitted?

Answer 33

either foodborne or person to person

Question 34

What can food borne intoxications be classified into?

Answer 34

* bacterial * fungal * chemical * plant * poisonous

Question 35

What are some bacterial food pathogens that cause intoxication

Answer 35

* staphylococcus aureus * bacillus cereus * clostridium * perfringens

Question 36

Summarise staph aureus

Answer 36

* faculative anerobe, produces spores * intoxication is caused by eating food contaminated with staphylococcal enterotoxins * the organism produces five different enterotoxins

Question 37

Summarise staph enterotoxins

Answer 37

* they are all heat stable * they are insensitive to pH changes * resistant to proteolysis enzymes * not affected by irradication * all five have a similiar potency

Question 38

Why does the majority of staph.aureus poisioning occur when microbial flora is reduced?

Answer 38

Staphylococcus aureus is a poor competitor and therefore grows poorly or not at all when growing together with other microorganisms

Question 39

What are some of the symptoms of staph aureus?

Answer 39

Incubation period is 1-6 hrs after consumption of food contaminated with at least 1.0 µg of enterotoxin. * Clinical signs include salvation, nausea, vomiting, abdominal cramps, sometimes diarrhoea with prostration. * Duration of illness is 24-72 hrs. * Dose of 1.0 µg or more is needed to cause disease

Question 40

Summarise bacillus

Answer 40

* gram positive, spore forming rod * Produces 3 different toxins (emetic and two diarrhoeal)

Question 41

What are the two diarrhoeal endotoxins?

Answer 41

a) hemolysin BL enterotoxin b) non-hemolytic enterotoxin

Question 42

What is the main source of bacillus?

Answer 42

it is frequently isolated from meat, eggs and dairy products * Cereal dishes e.g. rice, pulses, spice, mashed potatoes, herbs, vegetables, minced meat, cream and milk pudding. * Vegetative cells killed by cooking, spores are not * If cooked rice/pulses are not chilled, spores can germinate, bacteria grow and toxins produced

Question 43

What are the symptoms of emetic syndrome?

Answer 43

The syndrome is characterised by nausea, vomiting, abdominal cramps and sometimes diarrhoea that occur 1-6 hrs after consumption of contaminated food. The syndrome is associated with ingestion of rice and pasta based foods.

Question 44

What are the symptoms of diarrhoeal syndrome?

Answer 44

In the diarrhoea syndrome, patients experience profuse diarrhoea (watery stool), abdominal cramps and tenesmus (rarely vomiting) beginning 8 to 16 hours after ingestion of contaminated food. Fever is absent and symptoms resolve within approximately 12 hours.

Question 45

What are the three species of clostridum?

Answer 45

* C.perfringens * C. botulinium * C.difficile

Question 46

Where is the clostridium perfringens enterotoxin produced?

Answer 46

GIT