diseases_infectiondynamics&biosecurity

Question 1

what are the 4 disease categories?

Answer 1

genetic
environmental
nutrional disorder
infectious disease

Question 2

what are reasons for infectious diseases?

Answer 2

parasites
fungal infection
bacteria
viruses

Question 3

what is the health triangle ?

Answer 3

relationship between:

• host
• infectious agent
• environment

Question 4

name 2 parasites infectious diseases

Answer 4

salmon louse

aemobic gill disease

Question 5

what is pathogenicity?

Answer 5

p. refers to the ability of an organism to cause disease.

Question 6

what is virulence?

Answer 6

v. refers to the degree of pathology caused by the pathogen.
often correlates with the pathogens ability to multiply within the host.

Question 7

name 2 fungal infections/mycoses

Answer 7

crayfish plague

saprolegnia spec

Question 8

name 2 bacteria transferred infectious diseases

Answer 8

vibriosis
cold water vibriosis
winter ulcers
furunculosis

Question 9

name 2 viral transferred infectious diseases

Answer 9

PD: pancreas disease
ISA: infectious salmon anemia
IPN: infectious pancreatic necrosis

Pox virus –> gill infection
reovirus –> heart and skeletal muscle inflammation

Question 10

describe vibriosis and cold water vibriosis.

- what is the main and only difference ?

Answer 10

marine: - atlantic salmon and rainbow trout
- control : vaccination
- widespread distribution in marine water

difference:
- water temp.:
cold water vibriosis –> low water temp.
vibriosis –> high water temperatures

Question 11

what is the treatment against bacterial diseases ?

Answer 11

vaccination

Question 12

what are the three most common viral diseases for salmonids?

Answer 12

ISA(infectious salmon anemia),
pancreas disease (PD),
IPN (infectiuos panceratic necrosis)

Question 13

what are bacterial disease characteristics?

Answer 13

• reservoir= widespread in water
• farm populations
• pathogenicity at an infectiuos dose
• water temperatures, stress

Question 14

viral diseases charcteristics?

Answer 14

• reservoir= infected farmed fish
• farm populations
• pathogenicity is host specific
• water temp. and stress

Question 15

there are legislations about health status of ….

Answer 15

of country/regin of origin ("disease free")
of population (mandatory health control)

Question 16

there are only international health legislations. true or false?

Answer 16

false, international and national

Question 17

who/what regulates the helath status?

name a few

Answer 17

-OIE: world animal helath orgainzation
- the trade and disese regulation
the pancrease disease regulations
- the aquaculture management regulation

Question 18

there are three list, in which disease are chategorized.
chategroized based on what?
and on which of these lists can you find :
-furunculosis
-PD
-ISA

Answer 18

1=exotic
2=nonexotic
3=national list

ISA= nonexotic–> 2
PD and furunculosis –>3

Question 19

what are the two control strategies?

Answer 19

1. live with infection

2. keep the infection out

Question 20

what is the managemnet strategy, if a disease is introudced?

Answer 20

1. immediate remval of infected population
2. cleaning and desinfection
3. fallowing (stilllegen)of the site

Question 21

how can becterial diseases be treated?

Answer 21

antbiotics

Question 22

how can sea lice be treated ?

Answer 22

cleaner fish, mechanical methods, pharmaceuticals

Question 23

what are the three vaccination methods?

Answer 23

oral
immersion
injection (mannually/automatically)

Question 24

what are the vacine methods/types?

5

Answer 24

• inactivated-killed
• adjuvants injection
• subunit vaccines(–> create wek immune response)
• live vaccines (–>immune response)
• DNA vaccines

Question 25

at what lifetime of the production cycle are salmons vaccinated?

Answer 25

when they are smolts in the freshwater, before they get transportetd to the farm (or at the farm in sea water)

Question 26

what is RPS?- what does it describe?

Answer 26

RPS = (1- %deaths in vacinnated fish/%deaths in unvaccinated fish) *100 =relative percent survival -- >describes the vaccine impact= vaccine efficacy

Question 27

what does RPS= 90 mean?

Answer 27

high efficacy of the vaccine

Question 28

what does RPS=40 | mean?

Answer 28

low efficacy of the vaccine

Question 29

the use of antibitics is close to zero since 1995, and the fish production rapidly in increases since then. true or false?

Answer 29

true, due to vaccines

Question 30

what are the species that still have the highest antbiotic prescription?

Answer 30

- atlnatic salmon - marine species (altnatic cod, turbot, halibut) - other species: including cleaner fish -lumpfish

Question 31

how is the vaccine protection against PD ad IPN ISA?

Answer 31

PD=moderate IPN= unknown ISA=unknown

Question 32

what are the effects of fish vaccination?

Answer 32

-does NOT prevent pathogen introduction BUT: reduces risk for outbreak in the populat. -reduces spread of diesase within the far//to other farms/to wild fish -R0<1

Question 33

what is R0?

Answer 33

=basic reprodution number --> =number of secondary cases arising from a single primary case

Question 34

what is when R0 > 1?

Answer 34

each primary case wll produce more tha one secondary case --> epidemic

Question 35

what is when R0 < 1?

Answer 35

the infection will tend to die out

Question 36

what effect has vaccination on R0?

Answer 36

vaccination reduces the number of susceptible hosts --> R0 <1

Question 37

what does herd immunity mean?

Answer 37

even non-vaccinated individuals and poor-responders are protected through the immunity of the herd/population

Question 38

on what does the herd immunity depends on?

Answer 38

- depends on the proportion of immune individuals + vaccine efficacy + infection pressure

Question 39

what is "biosecurity" | /"biosecurity plans"?

Answer 39

= preventive methods to reduce the risk of transmission of infectious diesase. if the disease is introduced --> do control measures to reduce consequences/losses - reduce the risk of further spread

Question 40

what does "bio-exlusion" mean?

Answer 40

prevent disease introduction

Question 41

what are the biosecurity levels ? 4

Answer 41

- internationally - nationally regionally - area/zone - production unit

Question 42

what are source for pathogen introduction?

Answer 42

- biological material (e.g.smolt, eggs ) - wild fish - feed - water vectore: eqipment, transport, vehicles etc.

Question 43

what are generell important elements of biosecurity plans?

Answer 43

- mandatory health control of fish - suveillance - transport of stocking population -> standard, regulatins - water source--> hygienic quality - "all in-all out" (one generation --> one stocking and harvesting --> cleaning and disinfection etc.)

Question 44

what are imprtant elements of biosecurity plans on the farm?

Answer 44

- hygiene barries btween clean and un clena area - limited contact to other sites/populations - own staff, own eqiupment and operations - control of visitors - controll of feed and equipment

Question 45

What does the PD regulation fro 2017 say?

Answer 45

- norway divided into 4 zone (2 PD free zone, 2 surveillance zones (western/mid-norway))) - testing 20 fishes/each month all farms - vaccination mandatory in buffer zone (mid norway)

Question 46

what are control measures within PD-zone?

Answer 46

- coordinated production -seperated fish generations fallowing of sites -distance betw. sites -control with transport -surveillance testing vaccination

Question 47

how long does a zoneneed to be disease free that it can be declared as PD free zone?

Answer 47

10 years

Question 48

how does vaccination against PD effects a PD zone? - mortality - growth/day - discarded at slaughter

Answer 48

mortality rate sinks growth rate ≈unchanged discarded at slaughter = halve

Question 49

is PD transmitt over long distance easier/harder than ISA transmitt? relative risk higher or lower?

Answer 49

easiere --> relative risk is higher