Lec 14 - Food and water borne outbreaks

Question 1

What are the 3 types of contamination in food borne infections?

Answer 1

1. Pathogens in undercooked meat
2. Pathogens in meat during storage/prep
3. Pathogens producing toxins in food

Question 2

What is main reason for increasing food borne outbreaks?

Answer 2

City living = access to same sources

Question 3

Compare the food-born pathogens in developed vs developing countries

Answer 3

Developed = Salmonella, C. botulinum, VTEC, Campylobacter, norovirus, hepatitis A

Developing = shigella, cholera, parasites, Salmonella, ETEC

Question 4

What network is used to monitor food borne outbreaks?

Answer 4

International PulseNet using genomic data

Question 5

What do the sources of food borne outbreaks depend on?

Answer 5

• Changes in production/supply
• New/emerging antibiotic resistance
• Unexpected sources eg root crops

Question 6

What are the common sources of food borne outbreaks?

Answer 6

• Meat, fish, dairy
• Unhygienic prep
• Incorrect storage

Question 7

Who are most at risk of food borne outbreaks?

Answer 7

Children, elderly, immunocompromised, hospitalised, those in war/natural disaster zones, pregnant

Question 8

What are prions?

Answer 8

Highly infectious proteins that convert normal PrP proteins to aberrant ones, causing fatal neurological disease

Question 9

What is Kuru? Where was its occurrence? What was its source?

Answer 9

• Shaking disease with uncontrolled laughter and personality changes
• Papua New Guinea
• CJD patient consumed in cultural cannibalism

Question 10

What is norovirus? How is it transmitted? Where does it often occur and from what source? List the symptoms and treatment

Answer 10

• Caliciviridae virus often called stomach flu/gastro
• Faecal-oral route with 24-48hr incubation and 12-60hr duration
• Daycares, nursing homes, ships, food prep areas
• Contaminated shellfish
• Nausea and diarrhoea
• No vaccine and unculturable

Question 11

What is Salmonella? How is it transmitted? What is the common source and who is at risk of severe disease?

Answer 11

• Salmonella enterica G-ve bacillus with 2500 serotypes
• Faecal-oral route and can be zoonotic
• Gastroenteritis after 1-2 days then 4-7 day duration
• Children at risk of severe disease

Question 12

What is toxoplasmosis? How is it transmitted and from what source? What are the symptoms and treatment?

Answer 12

• Toxoplasma gondii
• Cysts in tissue by infecting nucleated cells of mammals
• Undercooked meat or meat with cysts from cat faeces
• Asymptomatic, persistent, no treatment

Question 13

What are fungal mycotoxins and their source? List examples of mycotoxins and the varying pathologies

Answer 13

• Fungal contamination of crops in storage
• Aspergillus, Fusarium and Penicillium
• Aflatoxins, ochratoxin, fumonisins, citrinin, patulin, Trichothecene
• Liver and renal toxicity, diarrhoea, neurotoxicity, cancer

Question 14

What are the 3 types of water borne transmission?

Answer 14

1. Drinking contaminated water
2. Bathing in contaminated water
3. Washing food in contaminated water

Question 15

What are the 3 types of disease resulting from water borne diseases?

Answer 15

1. Enteric
2. Systemic
3. Respiratory

Question 16

What is the main contaminant resulting in water borne outbreaks?

Answer 16

Open defecation contaminating water used for washing and drinking

Question 17

Where are water borne outbreaks most commonly seen? What is the potential issue with this information?

Answer 17

Europe, Africa, SE Asia
Lack of reporting from countries

Question 18

What system is used to monitor water borne outbreaks?

Answer 18

US = National Outbreak Reporting System (NORS) linked to waterborne disease and outbreak surveillance (WBDOSS) producing morbidity and mortality weekly report (MMWR

Question 19

How are hepatitis A and E transmitted? What conditions result from both? What are the complications of hepatitis E?

Answer 19

• Faecal-oral route
• Both = nausea, jaundice, diarrhoea, fever
• Hepatitis E = fulminant liver failure in pregnant

Question 20

What is cholera? What causes it and what is the source?

Answer 20

• Vibrio cholera
• Watery diarrhoea = severe dehydration
• Water, contaminated shellfish

Question 21

What is legionnaires disease? How is it transmitted and what is the source? What are the symptoms and who is most at risk?

Answer 21

• Legionella pneumophila
• Spreads by water esp ACs and amoeba in aquatic conditions
• Pulmonary infections
• Elderly at risk with 10% fatality

Question 22

What is schistosomiasis? What is the pathology of transmission? What are the symptoms and complications?

Answer 22

• Trematode blood flukes = S. mansoni, S. haemotobium, S. japonicum
• Paired worms live internally for 10-20yrs laying 1000s eggs/day
• Acute inflammation in lungs and skin
• Chronic in intestine, bladder and liver with cancer

Question 23

How do water-borne fungal transmissions occur? What is the most common fungal infection?

Answer 23

• Humidity increases mycotoxins and fungal skin infections
• Candidiasis most common