Environmental Impacts and Welfare Implications Flashcards
1
Q
Name 3 benefits of aquaculture:
A
- Food security and nutrition
- Economic growth through fish production and trade,
- Poverty alleviation and the creation of employment opportunities in rural areas.
2
Q
Why are there so many food poisoning cases attached to fish food products?
A
usually consumed lightly cooked, raw or pickled.
3
Q
Name 9 stages of the fish processing line.
A
- Gutting and de-heading
- Desliming
- Weighing
- Filleting
- Trimming
- Pinbone removal
- Skinning
- Fillet washing
- Grading
4
Q
Name 4 zoonoses associated with fish?
A
- Clonorchis sinensis
- Diphyllobothrium latum
- Anisakis
- Mycobacterium marinum
5
Q
What is clonorchis sinensis?
A
A trematode
6
Q
What is the clonchorchis sinensis infective stage?
A
Metacercariae
7
Q
Where is the metacercariae found?
A
- musculature
- subcutaneous tissues
- scales
- fins
- gills of cyprinids, clupeids (carp and ray-fin fish)
8
Q
Which other species is clonchorchis sinensis found in?
A
rats, cats, dogs and pigs.
9
Q
Where does Clonchorchis sinensis occur?
A
Hong Kong, China, Taiwan, South Korea
10
Q
How many people are affected every year from Clonchorchis sinensis?
A
35 million people
11
Q
How many species of fish are susceptible to Clonchorchis sinensis in China?
A
43 species of fish
12
Q
In humans, where is Clonchorchis sinensis found?
A
In the bile duct.
13
Q
What might an infection cause in humans with Clonchorchis sinensis?
A
Could be fatal as infection could cause pancreatitis and lead to liver carcinoma.
14
Q
What are the 6 stages of the Clonchorchis sinensis life cycle?
A
1, Embryonated eggs passed in faeces
- eggs are ingested by snail (miracidia –>sporocysts–> rediae –> cercariae)
- free-swimming cercariae encyst in the skin or flesh of fresh-water fish
- Metacercariae in flesh or skin of fresh water fish are ingested by human host
- Excyst in duodenum
- Adults in biliary duct.
15
Q
What is the most common species of Diphyllobothrium to infect humans?
A
Diphyllobothrium latum.
16
Q
Is Diphyphllobothrium found in marine or freshwater species?
A
Both
17
Q
Where is Diphyllobothrium latum found in fish?
A
In the musculature and viscera
18
Q
Name 5 other species of animal which can be involved in the diphyllobothrium life cycle?
A
- Birds
- Bears
- Seals
- Walruses
- Dogs
19
Q
Where is the diphyllobothrium latum found in humands?
A
In the mucosa of the ileum and jejunum
20
Q
Is it Diphyllobothrium latum asymptomatic, and if not, what are the symptoms?
A
Normally asymptomatic.
- it could cause:
1. malabsorption
2. anaemia
3. weight loss
21
Q
How many people are infected worldwide by diphyllobothrium latum?
A
9 million people
22
Q
What is diphyllobothrium latum and how is it treated?
A
It is a cestode - praziquantel is used to treat it.
23
Q
Name the 9 stages of the lifecycle of Diphyllobrothium latum?
A
- unembryonated eggs passed in faeces
- eggs embryonate in water
- coracidia hatch from eggs and are ingested by crustaceans
- procercoid larvae in body cavity of crustaceans
- infected crustacean ingested by small freshwater fish. procercoid larva released from crustacean develops into plerocercoid larva.
- predator fish eats infected small fish
- human ingests raw or undercooked infected fish
- adults in small intestine
- proglottids release eggs.
24
Q
What species does anisakis species involve?
A
marine crustaceans, fish, squid and mammals.
25
Where is anisakis larvae found in fish species?
In the viscera and muscle of many fish species.
26
what is the definitive hosts of anisakis?
marine mammals.
27
Where is anisakis species found?
Worldwide distribution but predominates in areas where raw and pickled fish are eaten most.
28
where is the adult anisakis found in humans?
In the intestine.
29
What are the two forms of anisakis?
Non-invasive (asymptomatic) and invasive (severe reaction, bloody stools, nausea, ulcers)
30
What else can anisakis result in?
Hypersensitivity
31
What species of anisakis causes a majority (90%) of human infection?
Anisakis simplex.
32
How is anisakis treated in humans?
Surgery
33
what is the 9 stage lifecycle of anisakis?
1. marine mammals excrete unembryonated eggs
2. eggs become embryonated in the water and L2 larvae form in the eggs
3. Larvae hatch from eggs and become free-swimming
4. free-swimming larvae ingested by crustaceans and mature into L3 larvae
5. Infected crustaceans are eaten by fish and squid, larvae migrate to muscles and tissues, and through predation, the larvae are transferred from fish to fish.
6. fish and squid maintain L3 larvae that are infective to humans and marine mammals.
7. when L3 is ingested by marine mammals, the larvae moults twice and develops into adult worms. adult worms produce eggs that are shed by marine mammals.
8. when ingested by humans, they become iincidental hosts through eating infected raw or undercooked seafood.
34
How is diagnosis of anisakis made?
Gastroscopic examination during which 2cm larvae can be removed.
35
What colour is diphyllobrothium latum?
Bright yellow
36
What does anisakis look like?
Small and transparent or white.
37
What is microbacterium marinum?
An ubiquitous resistant bacteria
38
What kind of species does M. marinum cause disease in?
Ornamental fish.
39
What is mycobacterium marinum commonly known as?
Fishermans/ Aquarist's finger.
40
What does mycobacterium marinum cause in humans?
A cutaneous nodular lesions with a slow antibiotic response.
41
What is a bivalve?
An aquatic mollusc with a hinged shell
42
What is the most common aetiological agents transmitted to humans by bivalve fish and why?
Enteric viruses because many shellfish areas are impacted by sewage.
43
How much water can oysters sieve per hour?
10-24 litres.
44
What can this filtering result in?
The accumulation of toxins, bacteria and viruses above the acceptable level.
45
Name 5 biological hazards associated with bivalve consumption:
1. Bacteria
2. Viruses
3. Chemical
4. Organic
5. Biotoxins
46
What are the 7 bacterial species associated with bivalve consumption?
1. Salmonella
2. Shigella
3. Vibrio parahaemolyticus
4. Vibrio vulnificus
5. Vibrio cholerae
6. Campylobacter
7. Listeria monocytogenes.
47
What are the 2 viruses associated with bivalve consumption?
1. norovirus
| 2. hepatitis A virus
48
what are the chemical hazards associated with bivalve consumption?
Heavy metals - mercury, cadmium, lead
49
Name 4 organic hazards associated with bivalve consumption?
1. Dioxins
2. PCBs (polychlorinated Biphenyls)
3. Polycyclic Aromatic Hydrocarbons (PAH)
4. Pesticides
50
Name 4 biotoxins associated with bivalves?
1. Paralytic shellfish poisoning (PSP)
2. Diarrhetic shellfish poisoning (DSP)
3. Amnesic shellfish poisoning (ASP)
4. Neurotoxic shellfish poisoning (NSP)
51
Name 4 zoonoses associated with shellfish?
1. vibrio species
2. Noroirus
3. Hepatitis A virus
4. Algal toxins
52
What are the two most important Vibrio species in shellfish?
V. parahaemolyticus and V. vulnificus
53
What is V. cholerae associated with?
raw sewage
54
What accounts for 40% border rejections of seafoods imported in the EU?
Vibrio species.
55
Where does vibrio vulnificus survive and what is it NOT associated with?
Lives in warm seawater >13 degrees.
NOT associated with raw sewage.
56
Name 6 clinical signs of vibrio vulnificus?
1. vomiting
2. diarrhoea
3. abdominal pain
4. septicaemia
5. death
Blistering lesions are also common
57
What is the most common human transmission source and when does it peak of vibrio vulnificus?
Oyster consumption.
peaks over summer.
58
What causes 95% of all seafood-related deaths?
Vibrio vulnificus
59
What might increase vibrio vulnificus in Europe?
Global warming
60
What does V. parahaemolyticus cause?
Gastroenteritis
61
What % of shellfish samples in UK are positive for V. parahaemolyticus?
around 30%
62
What is the incubation period of norovirus?
1-4 days.
63
When are patients susceptible to reinfection or norovirus?
Within 6 months --> 1 year of previous episode.
64
How can norovirus be avoided?
Cook oysters and shellfish well before eating them.
65
What is the incubation period of hepatitis A virus?
2-6 weeks - very stable virus.
66
Name 7 clinical signs associated with hepatitis A virus?
The signs are non specific:
1. Fever
2. Headache
3. Nausea
4. Vomiting
5. Diarrhoea
6. Abdominal pain
7. Jaundice
67
What is the normal outcome of hepatitis A virus?
It is self-limiting and rarely causes death.
68
In whom does overt hepatitis A develop?
Infected adults.
69
What does recovery from hepatitis A lead to?
Long-term immunity
70
What is responsible for the production of biotoxins?
Phytoplankton
71
What type of algal toxin is a persistent problem in UK coastal areas?
Diarrhetic shellfish poisoning (SHP)
72
Are PSP and ASP common or rare?
Very rare
| Only 107 cases of ASP since discovery - 4 fatal.
73
What is the particular problem with algal toxins?
They are resistant to cooking as well as freezing.
74
How are algal toxin risks reduced?
Harvesting areas are weekly sampled, reduced to monthly if supported by a risk assessment.
75
Name 5 control methods to improve the risks of bivalve safety?
1. Cooking
2. Freezing
3. Water depuration
4. Cleaning and disinfection
5. Monitoring bacteriological and viral contamination of bivalve molluscs.
76
Who carries out bacteriological and viral contamination assessments on bivalve molluscs?
Centre for Environment, Fisheries and Aquaculture service (Cefas).
77
what is Cefas?
A European Union Reference Laboratory
78
Name 7 tasks performed by Cefas?
1. information and guidance on analytical methods
2, Work with national reference labs on new methods (comparative testing)
3. new reseach methods
4. training courses and workshops
5. collaborating third country labs
6. provide scientific and technical assistance to EC
7. Help reference labs implement quality assurance systems (accredation)
79
What is the rule of fishery products destined to be eaten raw under EU food hygiene legislation?
It is frozen first.
80
What has to occur in fish products e.g. Anisakis?
There has to be inspection of the product and any visible parasites removed before being sold
81
What are the two methods to kill parasites in fish products?
freezing and cooking
82
When does cold smoked fish need to be frozen before consumption?
If the smoking process does not achieve a core temp of 60 degrees for at least one minute.
83
Do marinated and salting products have to be frozen before cosnumption?
Yes
84
What are the freezing guides for fishery products?
- 20C for not less than 24 hours or
| - 35 C for not less than 15 hours.
85
Name 4 FBO exemptions from this freezing protocol?
1. Fishery products are due to be heated to a level that will kill parasites e.g. 60C for more than one minute for parasites other than trematodes.
2. They have been frozen for long enough - at -18C for at least 4 days.
3. If the fishing groups of origin do not present a health hazard regarding parasites. no exemptions for wild fish authorised in the UK.
4. farmed fish, when cultured from embryos and fed on a diet that cannot contain parasites and have been raised in an environment free from parasites.
86
What is susceptbile to cooking temperature and what is not inactivated?
Parasites, viruses and bacteria are susceptible, bioxotins are not.
87
Name an organism that is targeted during the cleaning and disinfection protocol and what does it grow on?
Listeria monocytogenes (grows on organic residues e.g. fat and protein)
88
What occurs in good farming systems?
Shellfish are held in tanks of seawater that is continuously pumped through a UV chamber- depuration of water.
89
How does depuration kill bacteria?
bacteria of concern usually faecal therefore excreted and exposed directly to the UV light and die.
90
What is depuration not effective against and why?
Viruses because they are within the flesh and not excreted or exposed to UV light.
91
Is depuration effective against biotoxins?
Not consistently
92
What are the 5 classes of classification of shellfish harvesting areas:
A --> D
| A is the safest and D is the poorest quality.
93
What is category A?
Molluscs contain < 230 E.coli per 100g of flesh
| - can be harvested for direct human consumption
94
What is category b?
90% sampled molluscs <4,600 E.coli per 100g flesh, 10% <46,000 E coli per 100 g flesh
- Human consumption after depuration or class A re-laying area or heat treatment
95
What is category c?
<46,000 E. coli per 100g flesh
- human consumption after re-laying area for 2 months or more, depuration, or heat treatment.
96
What is category D?
>46,000 E. coli per 100 g flesh
- must not be harvested or offered for human consumption.
97
What might increase future occurance of food-borne outbreaks associated to seafood consumption?
> changes in climate
| > changes in eating habits
98
What could be an important reservoir for anti-microbial resistance?
Aquatic systems.
