Viral Diseases of Sheep & Goats (14) - End E2

Question 1

What are properties of poxviruses?

Answer 1

virus resistant to environment
proliferative “tumor-like” lesions
orthopoxviruses and capripoxviruses induce long-lasting immunity
diagnosis electron microscopy or virus isolation
transmission by contact and mechanically by arthropods

Question 2

What is ORF?

Answer 2

contagious ecthyma; contagious pustular dermatitis,
sore mouth

Question 3

What are clinical findings of ORF?

Answer 3

most common 3-6 month old lambs, although adults may be affected
lesions develop as papule, then pustules, then thick tenacious scabs, first at oral mucocutaneous junctions
usually the oral commisures
then spreading to muzzle and nostrils
rarely on tongue

Question 4

_____ occur in ORF and scabs are painful

Answer 4

Fissuring

Question 5

T/F: Systemic infection is common in ORF

Answer 5

FALSE - rare but may result in lesions on coronets, ears, nasal and buccal mucosal, around anus, vulva, or prepuce
can go to udders

Question 6

How is ORF transmitted?

Answer 6

transmission very rapid
occurs by contact with other affected animals or persisting scabs in the environment
virus is very resistant

Question 7

T/F: Humans can contract ORF

Answer 7

TRUE
persistent becomes a nodule and often itches
localized with occasional lymphadenopathy

Question 8

T/F: The vaccine for ORF isn’t really affected

Answer 8

TRUE - basically just giving herd weakened form of ORF

Question 9

What is ovine progressive pneumonia? (aka maedi visna)

Answer 9

economic significance within N America
decreased milk production
indurative mastitis
decreased weight gain for lambs
increased mortality of lambs

Question 10

What are clinical signs of ovine progressive pneumonia? (OPP)

Answer 10

slow progressive nature
in early stages, animal may only show signs after being stressed
eventually animal will become weak, and not keep up with rest of the flock
regional lymphadenopathy, proliferative arthritis, loss of body condition
respiratory signs include nasal discharge, coughing, flaring discharge

Question 11

How is OPP transmitted?

Answer 11

ingestion of infected milk or colostrum by neonate
direct transmission via respiratory droplets
some animals will remain asymptomatic but continue to shed infective organisms

Question 12

How do you diagnose OPP?

Answer 12

ELISA, agid, PCR

Question 13

How do you treat OPP?

Answer 13

no treatment - no vaccines
close herd to new additions
test all animals (seropositive removed from flock)

Question 14

What is caprine arthritis-encephalitis (CAE)?

Answer 14

multi systemic disease
- most common clinical manifestation is polyarthritis

Question 15

How prevalent is CAE?

Answer 15

seroprevalence is anywhere from 38-81%

Question 16

For CAE, the clinical presence of arthritis occurs in less than ____ of seropositive animals

Answer 16

25%

Question 17

What is the most common form of transmission for CAE?

Answer 17

doe to kid via infected colostrum or milk
horizontal transmission may occur between animals house together for extended periods of time
venereal transmission also possible

Question 18

What are the clinical signs of caprine arthritis-encephalitis?

Answer 18

arthritis
leukoencephalomyelitis
interstitial pneumonia
mastitis

Question 19

How do you control CAE?

Answer 19

testing (ELISA) and removal
kids can be protected by removing them from their does at birth

Question 20

Bluetongue virus is a _______

Answer 20

reovirus

Question 21

What are characteristics of reovirses?

Answer 21

resistant to environment
wide range clinical presentations
many serotypes with type-specific immunity
transmission by contact, fomites, common vehicle, arthopods

Question 22

Which species is primarily affected by bluetongue (catarrhal fever of sheep)?

Answer 22

sheep, also cattle and wild ruminants

Question 23

What are clinical signs of bluetongue in sheep?

Answer 23

fever
nasal discharge, salivation, reddening of buccal mucosa
swelling and edema of lips, gum, dental pad, tongue
foot lesions - laminitis and coronitis
rapid loss of condition
abortions and congenital deformities may occur

Question 24

What is the significance of bluetongue in cattle?

Answer 24

transmitted by culicoides sp fly biological vector

Question 25

What are these oral lesions characteristic of? (Could be others but keep this in mind)

Answer 25

FMD (foot and mouth disease)

Question 26

What are clinical signs of scrapie?

Answer 26

prion disease
damage to nerve cells - behavioral changes, tremor (especially of head and neck), pruritis, locomotor incoordination
loss of wool from pruritis

Question 27

Which breed of sheep are particularly susceptible to scrapie?

Answer 27

suffolk sheep

Question 28

How is scrapie transmitted?

Answer 28

not fully understood
infected animals contaminate pastures via placenta
animals become infected when they ingest pathogen
transmission is long

Question 29

How do you diagnose scrapie?

Answer 29

relies on detected of PrP (prion protein) in lymphoid tissue - tonsils, pharyngeal lymph nodes, rectal mucosa, third eyelid
post-mortem histological identification of degenerative changes to CNS

Question 30

How do you prevent scrapie?

Answer 30

reportable disease
herd management primary mode of prevention
National Scrapie Eradication Program