Respiratory Disease Sheep Flashcards
is respiratory disease usually a flock or individual problem?
- flock
WHat should be observewd on distance examination?
- Flock - look, listen
- demeanour (normal v sick)
- size variation (heterogeneity)
- nasal/ocular discharge?
- dyspnoea or resp distress
- coughing
- particularly bad animals
Main points of resp based PE on clinically affected sheep?
- temp
- resp (<20 but usually faster)
- lung sounds may be loud (poor correlation between lung sounds and pathology)
- HR
- size and BCS
- MMs
- Hydration status
How is definitive Dx usually made?
PME of affected animal (don’t let farmer sway you to cull maller unaffected sheep!)
How much is a PME? How much is carcasse disposal?
£30-£60
- carcasses disposal £20
WHat further diagnostics are possible for valuable aniamls?
- BAL (NB. many agents commensals of sheep resp tract so ? significance if found, better in calves)
- Ultrasound/rads
WHat is the main respiratory cuase of sudden death in sheep?
- peracute pneumonia (manheimia haemolytica, enzootic pneumonia) -> septicaemia (usually first lambing yearlings)
What is the main cause of acute or subacute ill-health, cough +- discharge in sheep?
- acute bacterial/viral pneumonias (+ fever)
- aspiration pneumonia (+ fever)
- parasitic pneumonia (No fever)
What are the most common presenting signs of rep disease in LAMBS? Causes and Pathophysiology?
- chronic pneumonia (mycoplasma or resolved enzootic pneumonia) -> lung dmage, poor weight gain, chronic ill-thrift and occasional cough
- multiple lambs affected
What are the most common presenting signs of resp disease in ADULTS? Causes and pathophysiology?
- chronic weight loss
- breathing difficulties
> ‘slow virus’ diseases eg. Maedi-Visna, SPA - lung tissue replaced with solid tissue
- only 1-2 animals affected at a time
Which URT obstruction may be seen in sheep? Prognosis?
- laryngeal constriction or damage
- laryngeal chondritis and abscessation esp. muscle breeds eg. suffolks
> can be fatal
WHat is the single most common respiraoty problem in sheep?
Pneumonia
- young animals
- ENDEMIC in UK and world
- multi-factorial aetiology
- predisposing factors: ventilation, age, stress
What are the most common pathogens involvd in ovine pneumonia?
- Manheimia Haemolytica (commensal)
- Mycoplasmas (commensal)
- PI3 and adenoviruses (predispose to 2* disease)
Which pathogens are less commonly involved in ovine pneumonia?
- Pasturella trehalosi
- Pasturella multocida
- Bordatella parpertussis
- Resp syncytial virus
- Reoviruses
WHat risk factors predispose ovine pneumonia?
> housing - close contact - poor ventilation - high humidity > mixing - ages -sources > young = greater risk > climate > stress - mixing - nutrition - husbandry
Which pathogens are involved in enzootic pneumonia of sheep?
- PI3 predisposing viral damage
- colonisation with m. haemolytica (pasteurella)
Clinical scenario associated with enzootic pneumonia?
- any age
- any season
- most commonly young lambs sudden death in young lambs (septicaemia) and pneumonia in lambs and ewes
CLinical signs of enzootic pneumonia?
- sudden death
- high fever (>40.3*)
- depression
- inappetent
- dyspnoea
- cough
- nasal discharge (may be frothy)
- poor thrift in recovered animals
Diagnosis of enzzotic pneumonia?
- hx, clinical signs
- PME +- histopath and culture of large colony from lung
- isolation of PI3/M. haemolytica from NASAL cavity IS NOT DIAGNOSTIC**
- need BAL
Tx of enzootic pneumonia outbreak? How may this be different for individual animal?
- prophylactic LA oxytet and vax
- individual: LA oxytet or tilmicosin
> limited Abx in sheep, think cascade
Why may oxytet not be effective in sheep?
- commonly used heavily for tx of chlamydophila abortions so may have developed resistence on farm
Give 2 common vax protocols for enzootic pneumonia
- Ewe
- sensitiser + booster 4-6 weeks later
- booster 4-6weeks prelambing to maximise colostrum levels - young lamb
- maternal antibody lasts 3-5 weeks
- vax then, booster 3-4 weeks later
What is enzootic pneumonia vax protocol commonly combined with?
Clostridial vaccine
Clinical signs of atypical pneumonia?
- death RARE
- low growth rates common
- occasional clinical disease
- usually subclinical
- flock signs of cough and nasal discharge
- dullness and loss of condition
Diagnosis of atypical pneumonia?
- hx, clinical signs
- PME
> clearly demarcated red-brown or grey areas of lung
> apical and cardiac lobes
> MYCOPLASMA OVIPNEUMONIAE
Prevention/control of atypical pneumonia?
- housing design and ventilation improvements
- v stocking density
- quarantine introduced animals (not all sheep carry mycoplasma)
Only important sheep lung worm?
Dictyocaulus filaria
When is peak larval contamination of dictycaulus filaria?
- autumn and winter (build up on summer pasture)
What aged lambs are most commonly affected?
Up to 1 year
- variation in individual susceptability
Clinical signs of parasitic pneumonia?
- coughing
- ^ RR
- nasal discharge
- if severe, weight loss
- death rare
Diagnosis of parasitic pneumonia
- hx, clinical signs
- larvae in feaces
- PME adult worms clearly visable in bronchi
- leasions in diaphragmatic lobes
Is resp parasitism as common a problem as GI parasitism?
No, basically no economic significance to farmers
- exception: severe lungworm infestation seen with paratuberculosis (johne’s) due to immunocompromise
Control of parasitic pneumonia?
= GI parasite control measures
- no vax
What type of virus causes maedi-visna? What does it cause clinical signs wise? When does it manifest?
- Lentivirus (slow virus)
- seen in 3yo +
- slow progression of signs
- dyspnoea, wasting and mastitis, arthritis
+- cough, nasal discharge
How is maedi-visna transmitted?
- vertical in coclostrum and milk
- some horizontal transmission
Does maedi-visna cause mortality?
not really, ~2% mortality but mainly due to premature culling as poor production milk etc.
Diagnosis of maedi-visna?
- Hx, clinical signs
- serology (individual/flock)
- PME: voluminous lungs, uncollapsed but will sink
- histopath
Treatment/prevention/control of maedi-visna?
- NO Tx
- Prevent disease introduction
> CheCs scheme attempt to eradicate from individual farms (certification) - control options = many!
> cull clinical cases
> cull all ewes when 4-5yo
> cull offspring of affected ewes
> testing and culling
> snatch lambs from seropositive ewes
> complete destock and replacement (ensure buying from accreditied source or could just buy them all back in!)
What is SPA also known as? What is it? Mortality?
- sheep pulmonary adenomatosis = ovine PA =Jaaksiekte
- retrovirus
- slowly progressive lung adenocarcinoma (common contagious tumour)
- long incubation
- transmission respiratory and vertical
- Mortality high on first instance then becomes endemic (losses 2-10%)
Clinical signs of Jaagsiekte?
- adult sheep (2-4yo)
- progressive resp disease
- weight loss
- wheelbarrow test to check for fluid coming out of the nostrils
= otherwise same as Maedi-visna
Diagnosis of Jaagsiekte?
- Hx and lcinical signs
- NO serology
- PME: tumours in lungs, enlarged consolidated lungs with frothy fluid in bronchi
- histopath
- may occour in conjuction with other diseases eg. Maedi-Visna just to confuse you!!
