Respiratory disease in sheep SDL

Question 1

List 5 ice-berg diseases in sheep

Answer 1

Maedi Visna
Ovine Pulmonary Adenocarcinoma
Caseous Lymphadenitis
Johne’s
Border Disease

Question 2

What is Maedi Visna

Answer 2

A chronic infectious retrovirus disease
infects lungs and nervous system

Question 3

How is Maedi Visna transmitted

Answer 3

aerosol transmission, increased by close contact
also milk and colostrum

virus does not live long in the environment

Question 4

What are the clinical signs of Maedi Visna

Answer 4

increased pneumonia and mastitis incidence is a chronic wasting disorder which also includes laboured breathing
low milk production leading to poor lamb growth

Question 5

What age sheep does Maedi Visna affect

Answer 5

All ages of sheep can be affected
>3 years old

Question 6

What is the presentation of Maedi Visna post-mortem

Answer 6

Animal have heavy grey coloured lungs

Question 7

How can Maedi Visna be diagnosed

Answer 7

blood testing is the only reliable method of detection

Question 8

How can you treat Maedi Visna

Answer 8

ultimately a fatal condition - no vaccine available

Question 9

Describe how you can reduce the risk of Maedi Visna

Answer 9

sourcing animals from accredited flocks
monitoring and testing new stock
reducing stocking density
increasing biosecurity

Question 10

What is Jaagsiekte also known as

Answer 10

Ovine pulmonary adenomatosis

Question 11

What causes OPA

Answer 11

a beta retrovirus which infects cells in the lungs

Question 12

what is OPA

Answer 12

a contagious tumour of the lungs of sheep
tumours can produce high levels of a white foaming fluid increasing the risk of secondary infections such as pasteurella

Question 13

How is OPA transmitted

Answer 13

typically aerosol and can also be passed through colostrum and milk

Question 14

Which animals are most susceptible to OPA

Answer 14

younger stock
but olders can also be infected
infection typically peaks in ewes around 4yrs and tups at 1-2 yrs

Question 15

What are the clinical signs of OPA

Answer 15

severe weight loss
laboured breathing
some animals may cough or produce a nasal discharge
infection can often appear as a sudden death

Question 16

How can you detect OPA

Answer 16

No blood test available
ultrasound lungs for tumours - scan and cull system
wheelbarrow test- will see fluid come out- not allowed now due to animal welfare concerns

Question 17

How can you diagnose OPA

Answer 17

fluid production
post mortem
PCR in the future

Question 18

What is the presentation of OPA post mortem

Answer 18

lungs are larger/ heavier than normal with areas of solid grey tumour

Question 19

Where should the probe be located when ultrasound scanning for OPA

Answer 19

at 6th/7th intercostal space

Question 20

Describe how you can control OPA

Answer 20

slaughter affected animals
buy from trusted sources
minimise common trough use
reduce stocking density

Question 21

What is caseous lymphadenitis (CLA) caused by

Answer 21

is a bacterial infection
Corynebacterium pseudotuberculosis

Question 22

Describe the transmission of contagious lymphadenitis (CLA)

Answer 22

enter through skin abrasions (may be microscopic), inhalation or ingestion

Question 23

How does CLA cause disease

Answer 23

infected wound will spread infection to the draining lymph nodes
bacteria will multiply and form a micro-abscess
this will coalesce into a larger abscess which will then wall off and the bacteria will grow and release an exotoxin

Question 24

T/F antibiotics are not effective against CLA

Answer 24

True - because they are not effective inside the abscess

Question 25

How long can CLA bacteria survive in the environment

Answer 25

up to 8 months- but is killed by sunlight up to 24 hrs in sheep dip

Question 26

Describe how CLA tends to be introduced to a flock

Answer 26

bought in infected animals potentially via fomite transmission through infected pus shearing is a risk time for spread aerosol if abscess is in lung

Question 27

Describe how you confirm CLA

Answer 27

bacteriology on the pus from a ruptured abscess or a blood antibody ELISA test

Question 28

Describe the clinical signs of CLA

Answer 28

vary depending on the location of the abscesses typically lumps and bumps on the head and neck

Question 29

List some potential ways to prevent CLA

Answer 29

buy stock from trusted sources increase boundary biosecurity separate infected animals no vaccine in the uk

Question 30

Which breeds is laryngeal chondritis associated with

Answer 30

texels, beltex and southdowns

Question 31

what is laryngeal chondritis associated with

Answer 31

short thick neck and high concentrate feeding

Question 32

How does laryngeal chondritis occur

Answer 32

suppurative lesions form within the arytenoid cartilage and narrow the lumen of the larynx causing severe dyspnoea with laryngeal stridor which can often be fatal

Question 33

Describe how you treat laryngeal chondritis

Answer 33

one-off dexamethasone injection with a week's course of antibiotics (amox/clav - off licence)

Question 34

does laryngeal chondritis normally reoccur

Answer 34

yes

Question 35

List the 5 main causes of bacterial pneumonia in sheep

Answer 35

Mannhaemia haemolytica mycoplasma speceies bibersteinia trehalosi pasturella multocida bordetella parapertussis

Question 36

What are the 5 differential diagnoses for coughing lambs

Answer 36

pasteurellosis atypical pneumonia viral pneumonia lungworm mycotic pneumonia

Question 37

What are the 2 types of pasturellosis

Answer 37

pasturellosis caused by Mannheimia haemolytica Pasturellosis caused by bibersteinia trehalosi

Question 38

How does pasteurellosis- Mannheima haemolytica, affect sheep and lambs

Answer 38

older sheep- pneumonia lambs- septicaemia (<12 weeks)

Question 39

List 8 clinical signs of pasteurellosis- mannheimia haemolytica in sheep/lambs

Answer 39

cough inappetence ocular-nasal discharge pyrexia toxaemia hyperpnoea tachypnoea dyspnoea

Question 40

what are 3 clinical signs of mycoplasma involement in pasteurellosis in sheep

Answer 40

fewer acute signs persistent dry soft cough poor growth rates

Question 41

List 5 risk factors for the development of pasteurellosis- Mannheimia haemolytica

Answer 41

concurrent infections with other resp pathogens environmental conditions- housing, stock density, temp extreme weather stress diet change

Question 42

List 4 post morteum signs of mannheima haemolytica

Answer 42

lungs purple-red, swollen and heavy sink in water straw yellow pleural exudate with fibrin clots tracheobronchial lining is red-purple with pink froth in airways

Question 43

List 4 post mortem changes seen with Bibersteinia trehalosi

Answer 43

coalescing haemorrhages in thoracic regions necrosis and ulceration of mucosa in pharynx, stomachs and oesophagus enlarged purple pharyngeal lymph nodes and lung consolidation pin point of hepatic necrosis

Question 44

Describe how to treat pasteurella in sheep

Answer 44

Oxytetracycline - first choice

Question 45

List 6 ways to reduce the risk of pasteurellosis in lambs

Answer 45

reduce stress avoid mixing sources of sheep good ventilation and airflow, no draughts introduce food change gradually- plenty of forage ensure sheep healthy- good immune response to challenge vaccinate to improve immune response

Question 46

What can be seen on PM with Mycoplasma ovipneumoniae

Answer 46

Dark red to grey raised areas on apical & cardiac lobes