Viral Diseases of Sheep & Goats (14) - End E2 Flashcards
What are properties of poxviruses?
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
What is ORF?
contagious ecthyma; contagious pustular dermatitis,
sore mouth
What are clinical findings of ORF?
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
_____ occur in ORF and scabs are painful
Fissuring
T/F: Systemic infection is common in ORF
FALSE - rare but may result in lesions on coronets, ears, nasal and buccal mucosal, around anus, vulva, or prepuce
can go to udders
How is ORF transmitted?
transmission very rapid
occurs by contact with other affected animals or persisting scabs in the environment
virus is very resistant
T/F: Humans can contract ORF
TRUE
persistent becomes a nodule and often itches
localized with occasional lymphadenopathy
T/F: The vaccine for ORF isn’t really affected
TRUE - basically just giving herd weakened form of ORF
What is ovine progressive pneumonia? (aka maedi visna)
economic significance within N America
decreased milk production
indurative mastitis
decreased weight gain for lambs
increased mortality of lambs
What are clinical signs of ovine progressive pneumonia? (OPP)
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
How is OPP transmitted?
ingestion of infected milk or colostrum by neonate
direct transmission via respiratory droplets
some animals will remain asymptomatic but continue to shed infective organisms
How do you diagnose OPP?
ELISA, agid, PCR
How do you treat OPP?
no treatment - no vaccines
close herd to new additions
test all animals (seropositive removed from flock)
What is caprine arthritis-encephalitis (CAE)?
multi systemic disease
- most common clinical manifestation is polyarthritis
How prevalent is CAE?
seroprevalence is anywhere from 38-81%
For CAE, the clinical presence of arthritis occurs in less than ____ of seropositive animals
25%
What is the most common form of transmission for CAE?
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
What are the clinical signs of caprine arthritis-encephalitis?
arthritis
leukoencephalomyelitis
interstitial pneumonia
mastitis
How do you control CAE?
testing (ELISA) and removal
kids can be protected by removing them from their does at birth
Bluetongue virus is a _______
reovirus
What are characteristics of reovirses?
resistant to environment
wide range clinical presentations
many serotypes with type-specific immunity
transmission by contact, fomites, common vehicle, arthopods
Which species is primarily affected by bluetongue (catarrhal fever of sheep)?
sheep, also cattle and wild ruminants
What are clinical signs of bluetongue in sheep?
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
What is the significance of bluetongue in cattle?
transmitted by culicoides sp fly biological vector
What are these oral lesions characteristic of? (Could be others but keep this in mind)
FMD (foot and mouth disease)
What are clinical signs of scrapie?
prion disease
damage to nerve cells - behavioral changes, tremor (especially of head and neck), pruritis, locomotor incoordination
loss of wool from pruritis
Which breed of sheep are particularly susceptible to scrapie?
suffolk sheep
How is scrapie transmitted?
not fully understood
infected animals contaminate pastures via placenta
animals become infected when they ingest pathogen
transmission is long
How do you diagnose scrapie?
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
How do you prevent scrapie?
reportable disease
herd management primary mode of prevention
National Scrapie Eradication Program
