Coughing Horses Flashcards
Ddx for LRT disease in foals and weanlings?
- EHV 1 and 4
- Equine Influenza
- Undifferentiated respiratory tract infectoin
- rhodococcus equi
- strep equi equi
- parascaris equorum
DDx for URT disease in foals and weanlings?
- EHV 1 and 4
- Equine influenze
- Strep equi equi
Causes of undifferentiated bacterial pnuemonia?
- strep zooepidemicus most common
- actinobacillus, klebsiella, s. aureus, bordtello, mycoplasma
CLinical signs of undifferentiated bacterial pneumonia?
- auscultable changes (may not!)
- mild pyrexia
- hx of cough
What further diagnostic test findings point t o undifferentated bacterial pneumonia?
> tracheal aspirate/wash - mucopurulent exudate > radiography - bronchointerstitial patterns > BAL/tracheal aspirate - ^ degenerate neutrophils with ic bacteria
Tx of undifferentiated pneumonia in foals
- Abx (culture and sensitivity, start with something good against STREP)
- rest
- dust free environment
Infectious causes of adult URT disease?
- equine influenza
- equine hepres virus 1 and 4
- EVA
- equine rhinitis virus
- Strep equi equi
Infectious causes of LRT disease in adults?
- equine influenze
- equine herpes virus 1 and 4
- EVA
- equine rhinitis virus
- strep equi equi
- strep zooepidemicus
- strep pneumoniae
- pastuerella/actinobacillus
How do VIRUSES that cuase LRT and URT disease start?
URT then 2* LRT (ie. with VIRUSES cannot have LRT without URT first!)
cf. bacteria which can individually affect LRT
Is URT or LRT disease more common?
LRT
What aged horses commonly get URT infection?
young (yearlings/2yo)
- older animals develop an immunity
Which horses is LRT infection common in? LRT bacterial or viral infection more common?
- all racing age groups
- especially 2yo flat racer and 4yo national hunt yards (ie. when they come into training and groups of horses mixed)
- bacterial more common than viral but can ocour in combination
bacteria or viruses most common cause of URT infection?
virus
Clinical presentation of all URT disease in adults?
- fever
- nasal discharge (serous with virus, pussy with bacteria)
- coughing
- enlarged submandibular LNs
Clinical presentation of LRT disease in adults?
\+- fever \+- nasal discharge - coughing - mucoid tracheal secretion - poor performance - may be subclinical and only found if frequently scoped
Is EHV 1 and 4 endemic anywhere?
Yes UK and worldwide
- 75% horses latent infection acting as reservoir for on-going infection
- stress activates (vax, foaling, travel etc.)
Sites of latency for EHV 1 and 4?
- bronchial LN
- submandibular LN
- trigem ganglia
Potential cause of reactiviation of EHV1/4?
EHV 2 maybe - no one knows
When are horses most likely first exposed to EHV?
foals/weanlings
- source of infection lactating mares (recrudescence due to foaling!)
- foal to foal spread
How long does EHV immunity last for?
3-5 months
Sources of EHV1+4 re-infection for adults? What does re-exposure cause?
- resp secretions
- foetus/placenta
- fomites
> mild/inapparent infection mostly
> unless broodmare affected in last trimester -> abortion
> ascending hindlimb paralysis due to neuro strain possible
Pathogenesis of EHV 1 and 4? Any signs specific to each virus>
> BOTH (may be subclinical)
- inhalation of virus
- incubation 3-7d
- replicates in URT epithelium -> URT signs
- potentially disseminates to LRT -> LRT signs
EHV1
- transported ot other organs in T lymphocytes
- viraemic ~ 3 weeks
- vasculitis (CNS disease, abortion, chorioretinopathy)
- 2* bacterial infection
Equine influenza seen worldwide except for where?
Nz and australia
Most common age affected by equine influenza virus?
2 - 3yo racehorses (young)
WHat is the most common cuase of URTI?
equine influenza virus
How is equine influenza virus spread?
Aerosol > 30m spread
Are vaccinated animals protected from EIV?
no, susceptible to infection within 2-3 months
- partial immunity may liit clinical signs but schedding still occours
Is the horse a dead end host for EIV?
No - may be shed t o dogs (previously thought they were dead end host)
Pathogeneis of EIV?
- inhalation
- URT -> LRT
- loss of ciliated epithelium -> compromise of ucociliary mechanism
- NO VIRAEMIA (doesn’t cause other signs, must be looked for in resp secretions not blood sample)
- may be associated with 2* bacterial infection
Which bacterial causes of LRT infection can be grouped together? What signs do they cause?
- Strep zooepidemicus
- Strep pneumoniae
- pasteurella/actinobacillus
> ONLY CAUSE LRT SIGNS NOT URT (unless 2* to viral infection which will always start URT -> LRT)
Which type of disease (URT v LRT) needs more diagnostics? Why?
- LRT needs more as could be bacteria/virus
- URT only really viruses and finding which virus will not alter t massively
What signs may be seen on endoscopy/LRT samples and haemotology with viral/bacterial LRT infection?
- mucopurulent discharge
- ^ degenerate neutrophils
> haem - neutropaenia followed by neutrophilia (bacterial)
- lymphopaenia followed by lymphocytoisus (virus)
- hyperfibrinogenaemia / SAA
FIrst stage of diagnostics for LRT disease?
Endoscopy - and take LRT samples culture
Diagnoses of virus? Is htis really necessary?
> Not necessary! Tx same for all viruses EHV - virus isolation from blood or nasopharyngeal swab - serology paired samples EIV - paired serology - virus isolation (weeks) - PCR - ELISA (quick tests available now)
Tx of viral infection?
- isolate
- limit stress
- maintain hydration
- NSAIDs to limit pyrexia and improve appetite
- rest
- monitor for 2* infection
Tx of bacterial infection?
- ABx
- rest
- improve environment (dust free etc.)
- antipyretics
- mucolytics (maybe)
- bronchodilators (maybe)
Disease prevention - can you avoid herpes and influenza virus? Are there vax for bacterial pathogens?
- No, endemic
- No!
Under jockeey club rules, what must horses be vax against?
Influenza
Difficulties/problems with influenza vax?
> immunity short lived
Strains out of date so not perfect
- vax companies need to update strains covered! But some will give cross immunity and does dampen spread of virus hence jockey club rules
When may horses race after influenza vax according to jockey club rules?
8th day after vax
ANNUALLY
How do FEI rules differ to jockey club?
Extra booster within 6months and 21d of competition
What age can you vax EHV 1 and 4 from?
5 months
Effects of EHV 1 and 4 vax?
- reduce clinical disease, nasal shedding and days of viraemia
- natural immunity still short lived (3-5 months) so still not great!
Which horses is EHV 1 and 4 most common in and why?
Broodmares to prevent reinfection and abortion
Non infectious causes of coughing in adult horses - common, fairly common and uncommon?
> common - RAO - SPAOPD - IAD > fairly common - aspiration pneumonia - pluropneumonia - pulmonary abscesses - left heart failure - epiglottic entrapment - URT foreign body > uncommon - TB - lungworm - tracheal stenosis/collapse - inhalation pneumonia - interstitial pneumonia - neoplasia
Other names for RAO?
Heaves, COPD, Broken Wind
Define RAO
- naturally occourring lower airway disease characterised by reversible airway obstruction
> neutrophil accumulation
> mucous production
> bronchospasm - lifelong condition (potential genetic component?)
Clinical signs of RAO. 2 main presentations?
Lower resp signs > acute and severe - respiratory distress - ^ resp effort - double expiratory effort - dyspnoea > chronic - poor performance - overt signs of resp dysfunction \+- cough \+- hypertrophy of abdo muscles
Diagnosis of RAO and main DDx?
- HX and clinical signs
- PE: assess airway inflam (tracheal wash/transtracheal wash, BAL)
> main Ddx bacterial pneumonia (non-degenerate/degenerate neutrophils) - on endoscopy: inflammation and corina blunting , mucous
- lab of tracheal aspirate: ^ neutrophils, NONDEGEN with NO bacteria, ^ mucus, Curshmann’s spirals of mucus plugs
Tx of RAO?
- envinormental management
- tx bronchoconstriction
- tx pulmnary inflammation
- tx pulmonary mucus accumulation
Tx of SPAOPD? What is SPAOPD?
- summer pasture associated obstructive pulmonary disease
> avoid pasture! put in stable, dust free management
Which animals is IAD common in?
- commonly young racehorses but actually ALL ages of sports horse
- escpecially on mixing eg. beginning of training
How does IAD differ to RAO?
IAD
- milder disease (only chronic form seen not acute, no difficult breathing at rest with IAD)
- definitive cause unknown (potentially bacterial, viral (but not EHV or rhinovirus) blood from EIPH, dusts, LPS, ammonia etc..)
Dx of IAD?
- ^ mucous
- ^ neutrophils OR eosinoophils/mastcells (2 forms of disease)
- may be bacteria, may not
Tx of IAD?
- environmental changes v dust
- ABx if indicated
- Interferon if indicated (but not shown to be effective really)
- corticosteroids if indicated
- sodium chromoglycate mast cell stabiliser if indicated
- omega 3 PUFA supplement may be prophylactic?
