EQUINE ID Flashcards
Which two equine notifiable diseases are ENDEMIC to the UK?
Contagious Equine Metritis (Taylorella Equigenitalis) Equine Viral Arteritis
Which two exotic NDs of horses are zoonotic?
Rabies
Glanders
Which 4 exotic NDs of horses are transmitted via a vector?
Equine Infectious Anaemia
Equine Viral Encephalomyelitis
West Nile Virus
African Horse Sickness
Which 4 equine diseases do we routinely vaccinate against in the UK?
EHV 1
EHV 4
Influenza
Tetanus
(also strangles)
What are the 4 features of salmonella that make it highly pathogenic?
Adhesion molecules
Invasion genes (intracellular)
Virulence Plasmids
Exotoxins
What are the 2 diarrhoeal exotoxins produced by salmonelaa?
cAMP Cytotoxin
Phospholipase A
Which endotoxin of salmonella causes macrophages to recruit neutrophils via IL-1 and TNF?
LPS
Describe the pathogenesis of salmonella?
- Intracellular infection
- LPS produced
- Inflammation
- Tissue necrosis
- Fluid and protein leakage
- Diarrhoea & endotoxamiea
- Circulatory Shock
What is a KEY predisposing factor for equine salmonella infection?
STRESS - inc susceptibility, lowers required spore dose
How many faecal cultures for salmonella must be negative before horse can be removed from isolation?
5 (q12-24h)
What should your differentials be for acute colitis in the horse?
Salmonella
C perfringens
C difficiles
Acute necrotic colitis and dysentery (colitis X)
Rotavirus
Ehrlicihia Risticii
Describe the gram staining and O2 requirements of c perfringens and dificile in the horse.
Gram + Bacilli Obligate anaerobes
Which clostridial disease is the most common in horses?
C. perfringens type A
How do horses acquire salmonella?
Persists in environment
How do horses acquire clostridial disease?
commensal in gut flora
How do horses acquire rotavirus?
Ingestion in naive horse
How does rotavirus cause diarrhoea in horses?
Villous Atrophy
Poor absorption
Osmotic diarrhoea
How long is the disease course for rotavirus?
5-7d
What is the incubation period for rotavirus?
18-24h
How long after recovery do foals shed rotavirus?
2w
Which pathogen is the most common cause of infectious diarrhoea in horses?
Rotavirus
What is the gold standard test for rotavirus?
Electronmicroscopy (virus in faeces)
Besides the gold standard test - what other testing can be done for equine rotavirus?
Latex agglutination ELISA
How can we prevents foals suffering from rotavirus?
Maternal Vaccine: 8/9/10m of pregnancy. protects for 60d
How is Ehrlicihia risticii spread?
Ingestion of snails and aquatic invertebrates ONLY
What is the common name for Ehrlicihia Risticii infection?
Potomac Horse Fever
How is Ehrlicihia risticii diagnosed?
Paired serum simple with rising titre.
Which two equine viruses have a primary neurotropism?
Rabies Bornavirus
Which arboviruses cause CNS disease in horses?
East/West/Venezuelan Equine Encephalitis Japanese Encephalitis WNV
Which viruses cause CNS disease by damaging the BBB?
EHV1
EH4
Equine infectious anaemia
What are the two CSF changes commonly associated with viral encephalitis?
Mononuclear Pleocytosis
Inc Protein Concentration
How should a horse with neurological disease be kept?
Dark & Quiet stable with padded walls
How often should a recumbent horse be turned?
q4-6h OR SLING
What are the signs of EHV-1?
Respiratory Abrotion Myeloencephalopathy
What are the signs of EHV-2?
Keratitis
What are the signs of EHV-3?
Coital exanthema
What are the signs of EHV-4?
Respiratory
What are the signs of EHV-5?
Multinodular pulmonary fibrosis
What are the signs of EHV-6 to 8?
NONE IN HORSES only infect donkeys
Why do neurological signs of EHV appear?
vasculitis and thrombosis of arterioles in brain and SC
What are the possible neurological signs of EHV-1?
Ataxia (HLs or all 4) Cauda equina possible CN involvement
What are the “cauda equina” signs?
Bladder atony Flaccid tail/anus Perineal hypoalgesia
How is EHV-1 diagnosed?
PCR (nasal swab) also ELISA possible
What may be seen in the CSF of a horse with EHV-1?
Xanthochromia
How long does recovery from EHV take?
Days to Weeks (up to 1y)
How can we treat the vasculitis associated with EHV-1?
NSAIDs, aspirin ?steroids
How do we prevent EHV-1 from causing neuro signs?
can vaccine for EHV1/4 but ineffective on neurological form
What type of virus is rabies?
Rhabdovirus (f) Lyssavirus (g)
Where does rabies replicate?
Spinal root ganglia
How long is the rabies incubation period?
9d-1y
What 4 things cause variation in rabies incubation period?
Virus strain host species inoculum proximity of inoculation to CNS
What are the 3 forms of rabies and what are they related to?
LOCATION
Paralytic: Spinal
Dumb: Brain Stem
Furious: Cerebrum
Whichis the most common form of rabies in horses?
Spinal: localised hyperaesthesia & progressive ataxia
How is rabies diagnosed?
PM! negri bodies in neurones
What is the Tx for equine rabies?
NOTHING - kill on suspicion
Which Group A arboviruses (Togaviridae) infect horses?
EEE WEE VEE
Which Group B arboviruses (Flaviviridae) infect horses?
WNV Japanese encpehalitis
What is the natural reservoir for WNV?
Birds
What is the vector for WNV?
Culex mosquitos
What neurological signs accompany WNV?
Fasciculations over body (esp head) Weakness/Ataxia CN deficits decreased mentation
How do we treat WNV in the UK?
NSAIDs DMSO/Mannitol C/Ss
How do we test for WNV?
Ag specific ELISA
Which exotic, notifiable equine diseases cause respiratory signs?
Equine Viral Arteritis African horse sickness
Which respiratory virus is ONLY a problem in SCID foals?
Adenovirus
How long is the incubation period for equine influenza?
24-48h
What are the 5 main signs of equine flu?
Pyrexia
Nasal discharge
Coughing/Tahcypnoea
Inappetance/WL
Retropharyngeal Lymphadenopathy
Name the 5 Ddx for equine flu.
Strep equi var equi
EHV
Equine Rhinitis virus
Adenovirus
Equine Arteritis Virus
Which groups of horses are at high risk for equine flu?
Large groups of young horses
Which surface marker of flu facilitates entry to the host cell?
Neuraminidase
How do secondary infections occur in equine influenza?
Damaged cilia and epithelium allow bacterial entry
How much rest should a horse take after influenza?
1 week off for each day of fever (50-100d normal)
How do we diagnose equine influenza?
Isolate virus from nasal swab/tracheal wash
How do we Tx equine flu?
NSAIDs Air Hygiene antimicrobials if secondary infection
What does the equine flu vaccine target?
Haemaglutinin
What is the british horseracing guidelines on flu vaccines?
1st vac
2nd 21-92d later
3rd 150-215d later
booster WITHIN 365d
Where does EHV cause inflammation in the respiratory tract?
URT - rhinitis, tracheitis and pharyngitis
Where does EHV remain latent?
CD8+ T cells Trigeminal Neural Ganglion
How long is the incubation period for EHV?
3-7d
What are the clinical signs of EHV? (5)
Biphasic fever
Lethargy
Inappetence
Oedema/hyperaemic mucosa
Serous-mucopurulent discharge
What additional clinical signs are seen in foals with EHV 1/4?
Icterus
Leukopenia, neutropenia
Petechial haemorrhage
Severe pneumonia
How is EHV diagnosed?
Isolate virus from nasal swab/tracheal wash
What is the protocol for EHV1/4 vaccination? (normally and in pregnant mare)
1st: 5m old
2nd: 4-6w later
Booster: 6m Preg: 5, 7 and 9m
Which type of virus is equine rhinovirus?
Picornavirus
What are the common signs of equine rhinovirus?
Mild resp disease 3-5d Fever, anorexia, serous nasal discharge
Which coat protein is responsible for species susceptibility in rotavirus?
VP4
Which type of virus is equine viral arteritis?
Ateriviridae
Which horses suffer persistent infection of equine viral arteritis?
Stallions - testosterone responsible for maintenance in host
What are the three routes of spread for EVA?
Respiratory Venereal Transplacental
What is the incubation period of EVA?
3-14d
How do most horses with EVA present?
SUBCLINICAL!! do not often have signs
What are the clinical signs of EVA?
Fever/Depression/Anorexia Respiratory signs Peripheral Oedema Severe: generalised vasculitis
What must we be aware of with breeding mares and EVA?
Causes abortion at 3-10m
how do we diagnose EVA?
serology paired samples 21-28d apart
What are the 3 reservoirs of AHS?
Dog Zebra Elephant
What are the 4 major pathological features of AHS?
Severe vascular endothelial damage
Resp/CV damage
Protein rich fluid leakage into intersitium
Oedema
Where are the 4 places we may fins oedema in AHS?
Lungs, thorax, pericardium, Head
What are the 4 recognised forms of AHS?
Pulmonary form (fatal 1-4d) Cardiac form Mixed form Horse sickness fever (mild)
Apart from pulmonary oedema, what signs may we expect in pulmonary AHS? (4)
Fever & sweating Cyanosis Recumbency Death NO loss of appetite
Apart from hydropericardium, what signs may we expect in cardiac AHS? (6)
Persistent Fever Head/Neck oedema Petechiae on MMs Dysphagia Mild colic Slow death
Which pathogen is responsible for stranges?
Strep equi equi
Which two areas are most commonly targeted by strangles?
URT Head LNs
What are the main clinical features of strangles?
Pyrexia/Dull/anorexia Nasal discharge Lymphadenopathy GP empyema
Which is the latest clinical sign to develop after strangles infection?
Lymph node abscessation
Dyspnoea is a common complication of strangles. How do we treat it?
Tracheostomy
What is bastard strangles?
Transient bacteraemia Abscesses in other LNs
Which type of hypersensitivity is purpura haemorrhagica?
Ab-Ag complex (type III)
Which respiratory disease may cause purpura haemorrhagica?
Strangles
How do we treat purpura haemorrhagica?
Immunosuppression