Disease control in animals for PH

Question 1

Infections can be controlled by interventions that act in which 2 ways?

Answer 1

Prevent or reduce transmission

Reduces susceptible population

Question 2

How can transmission be reduced/prevented? Give an example of each

Answer 2

Prevent contact between the infected and susceptible individuals - biosecurity
Remove infected individuals - culling
Reduce ability to transmit - vaccinate

Question 3

How can the susceptible population be reduced? Give examples

Answer 3

Improve immunity e.g. vaccination
Make individuals harder to infect e.g. probiotics
Remove a susceptible population e.g. culling

Question 4

What are the 2 serovars for Salmonella enterica?

Answer 4

S. enterica serovar Typhimurium

S. enterica serovar Enteritidis

Question 5

What hosts does salmonella infect?

Answer 5

Any

Mainly poultry for S.enterica serovar Enteritidis

Question 6

What hosts do Camplyobacter bacteria mainly affect? (LA)

Answer 6

+++ Poultry (C. jejuni)
+ Pigs (c.coli)
+ Ruminants

Question 7

What hosts does E.coli affect? (LA)

Answer 7

+++Cattle

+Ruminants

Question 8

How are Salmonella, Campylobacter and Escherichia coli transmitted in a herd/flock?

Answer 8

Faecal shedding

Oral/faecal route

Question 9

Salmonella enterica serovar Enteritidis also has another tranmission route except faecal/oral. What is this?

Answer 9

Vertical transfer

To eggs

Question 10

What are the main colonisation sites for Salmonella, Campylobacter and E.coli?

Answer 10

Lower intestinal tract (most)

Caeca (chickens)

Question 11

What disease does salmonella cause? What does this depend on?

Answer 11

None, diarrhoea or invasive systemic disease
Reproductive tract infection (Salmonella serovar Enteritidis)
Host and isolate

Question 12

What does campylobacter cause? (LA)

Answer 12

None to mild/moderate D+

Question 13

What does E.coli cause?(LA)

Answer 13

None - adults as commensal

D+ in calves

Question 14

How is Salmonella entered into the food chain?

Answer 14

Contamination of meat by gut in abattoir
Contamination of meat in animal lifetime
Faecal contamination of eggs
Transomarian infection of eggs (S. eneteria serovar Enteritidis)

Question 15

How is Campylobacter entered into the food chain?

Answer 15

Contamination of meat by gut during abbatoir

Liver infection

Question 16

How is E.coli entered into the food chain?

Answer 16

Contamination of meat from guts or hide

Contamination of crops by infected manure

Question 17

Do Salmonella, Campylobacter and E.coli have specific legislation for control?

Answer 17

Salmonella - yes

Others - no

Question 18

How are these bacteria controlled on farms?

Answer 18

Vaccination
Surveillance
Biosecurity and hygeine
Probiotics (Salmonella only)

Question 19

What has been the biggest cause of the fall in Salmonella levels?

Answer 19

Vaccination

other factors - hygiene/biosecurity, probiotics, heat treatment of feed

Question 20

What is the Lion Mark Scheme? What year did it come into action?

Answer 20

Voluntary Scheme of hygiene, biosecurity standards and routine surveillance
1998

Question 21

What does current Salmonella surveillance require for broiler chickens going to slaughter or layer chickens?

Answer 21

2 swabs per flock

Within 3wks of slaughter/regularly for layers

Question 22

What happens if layers test positive for Salmonella?

Answer 22

Eggs can’t be class A

Question 23

How does the Salmonella vaccine work?

Answer 23

Inject killed bacteria then live bacteria into water

Question 24

Which poultry are not able to receive the Salmonella vaccine?

Answer 24

Broilers

Question 25

Biosecurity works well for Salmonella. Give examples of biosecurity

Answer 25

Vehicle wheel wash
Concrete around buildings
Specific equipment and clothing between houses
Vermin proof

Question 26

Why do biosecurity failures allow campylobacter?

Answer 26

More transmissible than others (Salmonella)

Transmissible via fomites

Question 27

Campylobacter can also be due to thinning. What is this?

Answer 27

Overstocked birds

Then depopulated and moved to another farm

Question 28

Why is it so important for equipment in slaughter house to be clean?

Answer 28

High production speed

200 animals minute - fast cross contamination

Question 29

What parts of the body does campylobacter infect in poultry?

Answer 29

Caeca
Liver
Muscle

Question 30

Why may animals with disease be culled?

Answer 30

Welfare reasons

Prevent disease transmission

Question 31

Why is preventing stress important for preventing transmission of disease?

Answer 31

Stress increases faecal shedding

Reduces immune function

Question 32

What is competitive exclusion?

Answer 32

Give microflora to animals that promote gut health and inhibit pathogens

Question 33

What care can be taken in slaughter houses to reduce disease?

Answer 33

Avoid gut/faecal contamination

Carefully remove GI tract (difficult as fast production)

Question 34

Why are antibiotics not given anymore?

Answer 34

AMR

Question 35

What can be given in livestock as a therapeutic treatment of disease? What are the problems of this?

Answer 35

Bacteriophages - viruses that infect bacteria

Resistance may develop, host specific range

Question 36

What post-slaughter control of meat can reduce disease?

Answer 36

Rapid chilling/steaming
Wash in chlorinated water
UV treatment
Bacteriophage treatment