goats and sheep Flashcards
CAE/MAEDI- VISNA
caprine arthritis/encepahlitis
OIE
aetiology of CAE/Maedi
, enveloped, single strand RNA, lentivirus from retroviridae fam (small rum lentiviruses)
CAEV
MVV
CAE MOT
- MOT: infected colostrum/milk (pooled colostrum) direct contact, contaminated fomites/needles, experimental = in utero, sexual, during birth
CAE HS
- HS: dairy goats, rare in meat/fibre breeds. Prevalence increase w age. Infected young
- sero + for life. Seroprevalence = >65% in high income economies
pathogenesis CAE
- unclear
- infected macrophages absorbed through GI mucosa spread through body periodic virus multiplication + macrophage maturation lymphoproliferative lesions (synovial membrane, choroid plexus, lungs, udder) humoral and cell immune response but it’s not protective
- persistence due to CAEV sequestered as provirus in host cells
signs CAE
arthritis - swelling of joints, lameness, joint deformities, reduced ROM, pain
enchepalitis - ataxia, weakness, head tilt, tremor/involvuntary movements
mastics - hard swollen udder, reduced milk, lumpy udder
pneumonia - respiratory signs - difficulty breathing, nasal discharge, coughing (respiratory signs are less common)
general signs of infection - weight loss, reduced growth rate, poor coat conditions
diagnosis of CAE/MVV
- presumptive = signs + history
- VI or PCR. AGID more specific but less sensitive than ELISA + = infection but doesn’t mean signs are caused by CAEV kids at birth get antibodies 4-10w after infection
- Colostral antibodies can last up to 90d
differentials CAE/MVV
- Mycoplasma/traumatic arthritis, spine abscesses, trauma, listeriosis, Polioencephalomalacia, rabies, caseous lymphadenitis if pulmonary form
treatment CAE/MVV
- No treatment, no vaccine, foot trimming, NSAIDs
MVV
- Maedi visna = Icelandic for laboured breathing + wasting (paralysing meningoencephalitis)
- Ovine progressive pneumonia (OPP)
- CAE + MV = small ruminant lentiviruses (SRLVs)
- 5 genotypes : A-E
o A (1-13): classical MVV strains. Some infect both sheep and goats
o B: classical CAEV strains
o C: both goat and sheep
o D & E: goat strains
o Possible recombination between SRLV = new vairnats - AB = widespread
- CDE = specific
o Genotypes C (Norway), D (Spain and Switzerland) and E (Italy) appear to be limited to small geographic areas in Europe - Texel + Leicester most likely to become ill
- Maedi = most common form, adult sheep. Wasting + progressive dysnpnea, no fever, depress or bronchial exudate. Eventually fatal (anorexia/2nd bact pneumonia)
- Visna = hindlimb weakness, head tilt, ataxia. Lasts 1y
- MVV can sometimes cause arthritis
- PM = enlarged, firm lungs that don’t collapse. Mottled emphysematous with grey/brown consolation
ORF
contagious ecthyma
ORF
- Highly contagious, zoonotic, viral pustular dermatitis
- Usually resolves spontaneously and the mortality rate is generally low
aetiology of ORF
- Parapoxvirus, Family Poxviridae
- Highly resistant to drying – survives on dry crusts for 12y + wool + hides for 1m after lesions have healed
SOI ORF
sick and carrier animals
POE ORF
cuts + abrasion of skin
MOT ORF
direct contact and fomites
HS ORF
Sheep and goats (goats more severe), young artificially reared lambs, older lambs autumn on pasture + winter in feedlots. Ungulates (alpaca, reindeer, elk, chamois, humans, rare in dogs + cats)
GD ORF
worldwide
pathogenesis ORF
- Papules vesicle pustule encrusts
- coalesce of multiple discreet lesions formation of large scabs
- proliferation of dermal tissue verrucous mass underneath
- humans = lesions on hands + face, PPE, mistaken for anthrax
signs ORF
- Incubation: 2 to 3 days
- Hyperaemia + pustules on mucocutaneous junction of lips extends to mucosa of buccal cavity
- Pustules crusts verrucose mass (2nd bact)
- Lambs dams lesions on udder
- Lesions on feet + dermatophilus congolensis strawberry foot rot (lameness)
- Anorexia, not gaining weight, abandon kid. Uncomplicated resolve in 1-2m
diagnosis ORF
- Lesions characteristic, PCR, electron microscopy of scab
differentials ORF
- Ulcerative dermatitis (usually older), FMD, bluetongue, staph folliculitis
treatment ORF
- supportive care: Tube feeding +Antibiotics as needed for secondary infections
control ORF
o quarantine new animals, clean + disinfect. Difficult to remove once in herd
o live vaccine for where infections have occurred in past – isolate until vaccine scabs have gone. Not in pregnancy.
o Immunity 18m after natural infection – highly resistant
CATS ORF
- Lesions of feet, face of back. Cauliflower like/proliferative ulcerative. Spontaneous healing or euthanasia
Dogs ORF
- Circular areas of acute, moist dermatitis with ulcers + scabs around head. Outcome not described
caseous lymphadenitis
- chronic infectious disease of sheep and goats
- manifesting as abscesses of peripheral/internal LN + organs
aetiology of caseous lymphadentiis
- Corynebacterium pseudotuberculosis, gram +, non-motile, non-sporulating, non-capsulated
- 2 biotypes on ability to reduce nitrate-ovis = nitrate neg, equi = nitrate +
- Exotoxin phospholipase D + virulence factor mucolic acids provides protection
- Survives in soil 8m, bedding for 2m
SOI caseous lymphadenitis
- SOI: sick animals with or without visible clinical symptoms (pus from lesions)
POE caseous lymphadenitis
- POE: ski/MM – shedding, castration, tail docking
MOT CL
- MOT: direct contact or contaminated environment
HS CL
- HS: sheep + goats, prevalence increase w age (shearing) all breeds – merino increase – thinner skin, neck wrinkles
pathogenesis CL
- Entry via skin/MM exotoxin increase vascular permeability dissemination to LN
- Survives + replicates in macrophages (helped by mucolic acids) rupture + bacteria are released
- Replication, attraction + death of inflam cells abscesses (onion ring formation)
o onion ring – concentric bands due to repeated stages of necrosis and capsule formation (green which is debris from cell and bacteria, large amount of eosinophils which is why it’s a little green)
signs CL
- incubation 1-3m
- external form= abscesses on peripheral LN swollen, firm, fibrous capsule hairless open draining abscess purulent w no odour heal w scarring. Recurrence common
- internal form = chronic weight loss, thin ewe syndrome. Often lung abscesses so cough, fever, purulent nasal discharge, tachypnoea
diagnosis CL
- external abscesses= highly suggestive
- definitive = culture of pus from intact abscess
- synergistic haemolysine inhibition test to detect antibodies to exotin – shows exposure not cause
differential CL
- morel’s disease = staph aureus subsp anaerobicus
- t. pyogenes, p. multocida, actinobacillosis, TB, lymphosarcoma, other causes of chronic weight loss
treatment CL
not curable’ – surgical drainage, atb – difficult to penetrate abscesses, cull
control CL
- Cull, strict biosecurity, prevent skin injuries, clean equipment, vaccine
public health CL
- Zoonotic potential
- Rarely long + recurrent lymphadenitis through cuts (farmers + shearers). Ingestion of unpasteurised milk from affected animals
