Disease control in animals

Question 1

Based on R0, in which 2 ways can infection be controlled in a population, describe them?

Answer 1

• Preventing or reducing transmission: prevent contact between susceptibles and infected
• Reduce the susceptible population: improve immunity, vaccination, genetic resistance

Question 2

What are 2 examples of major foodborne pathogens in the UK, how do they enter the food chain?

Answer 2

Campylobacter
Salmonella
- Contamination of meat by gut contents at slaughter/processing

Question 3

What is the lion mark scheme?

Answer 3

A voluntary scheme of hygiene and biosecurity standards couple to routine surveillance for Salmonella

Question 4

What was the target of National control plans?

Answer 4

To reduce salmonella in broilers to below 1%

- Set out standards for biosecurity, controls and surveillance

Question 5

What does a positive salmonella result mean for layers?

Answer 5

Eggs cannot be served as class A table eggs - has to be used as liquid in catering

Question 6

Who is now vaccinated for salmonella under NCP?

Answer 6

All layers and breeding birds

Question 7

Why are production broilers not vaccinated under NCPs for Salmonella?

Answer 7

Wont get enough of an immune response before slaughter

Question 8

What farm system allows disinfection between laying flocks and broiler crops?

Answer 8

All in, all out

Question 9

Biosecurity is good for salmonella, but what can small breakdowns in it lead to?

Answer 9

Campylobacter transmission leading to positive broiler flocks

Question 10

How can campylobacter be spread by breaks in biosecurity?

Answer 10

Fomite transmission via boots, clothing and flies

Question 11

What acts as the biggest opportunity for infection spread of campylobacter?

Answer 11

Intensive production, transport and processing

• thinning birds, overstocked
• feed withdrawal and transport leads to stress and increased shedding from infected birds
• rapidly growing broiler birds have poor immune systems

Question 12

What makes chickens a good target for genetic susceptibility?

Answer 12

Rapid generation time for breeding

Question 13

What are probiotics?

Answer 13

Single bacteria species that promote gut health and inhibit pathogens - competitive exclusion

Question 14

What are prebiotics?

Answer 14

Feed additives that promote a good microbiome

Question 15

Why are antibiotics no longer considered?

Answer 15

Rise in antimicrobial resistance, can prolong low levels of infection

Question 16

What should be avoided at slaughter/processing to prevent contamination?

Answer 16

Avoid gut/faecal contamination

Question 17

What are some post-slaughter controls?

Answer 17

Treatment of carcass/processed product
Gamma irradiation kills most bacteria species 
Lactic acids treatment of carcasses
Rapid surface chilling 
UV treatment
Bacteriophage treatment