Unit 4 - Equine Respiratory Flashcards
What are the common causes of infectious respiratory disease in neonates (<2 mo)?
Contaminated amnion/meconium aspiration
EHV-1/EHV-4
Influenza
EVAV
What is the less common cause of infectious respiratory disease in neonates (<2 mo)?
Adenovirus
What are the infectious causes of respiratory disease in older foals (>2 mo)?
Rhodococcus equi
ERAV/ERBV
What are the non-infectious causes of respiratory disease in foals?
Pre-maturity/dysmaturity
Guttural pouch tympany
Congenital defects - choanal atresia
What are the common infectious causes of respiratory disease in adults?
EHV-1/EHV-4 Influenza ERAV/ERBV EVAV Streptococcus equi ss equi Aspiration
What are the less common infectious causes of respiratory disease in adults?
Sinusitis
EHV-5
Fungal infections
Lungworms
What respiratory FAD occur in adults?
African horse sickness
Glanders
Hendra
What are the non-infectious causes of respiratory disease in adults?
EIPH RAO/IAD DDSP Neoplasia Pulmonary edema Nasopharyngeal cicatrix Toxin-associated interstitial pneumonia Acute respiratory distress syndrome Acute hypersensitivities/adverse drug reactions
What is bronchopneumonia associated with in foals?
Aspiration of contaminated amniotic fluid or meconium aspiration
Hematogenous spread via sepsis
What are the common agents of bronchopneumonia in foals?
E. coli, Klebsiella, Pasteurella, Actinobacillus
What is bronchopneumonia in adults associated with?
Aspiration of upper respiratory or GI flora
Long distance transport, stress, and recent viral infection
What are the common agents of bronchopneumonia in adults?
Streptococcus equi ss zooepidemicus, Pasteurella, Actinobacillus
What may bronchopneumonia progress to in adults?
Pleuropneumonia
What agents are associated with pleuropneumonia in adults?
Bacteroides, Peptostreptococcus, Fusobacterium
What clinical signs are associated with bronchopneumonia?
Anorexia, fever, cough, depression, tachypnea, dyspnea, abnormal lung sounds, nasal discharge, weight loss, and pleural pain
What CBC abnormalities are associated with bronchopneumonia?
Leukocytosis, neutrophilia, hyperfibrinogenemia
How is bronchopneumonia diagnosed?
radiographs, U/S, and culture (TTW ideal)
How is bronchopneumonia treated?
Antibiotics - broad spectrum
NSAIDs
How is pleuropneumonia treated?
Pleural drainage, thoracotomy
What is the etiologic agent of rhinopneumonitis?
EHV1 and 4
How is rhinopneumonitis transmitted?
Inhalation (droplet/aerosol)
Occasional transmitted in utero
What clinical signs are associated with rhinopneumonitis?
Primarily respiratory syndrome (subclinical to mild) - mild fever, serous nasal discharge, depression
Also causes abortions and neurologic disease
When can there be severe disease associated with rhinopneumonitis?
Severe disease when secondary infection with bacteria occurs or when foals are infected at birth
How is rhinopneumonitis diagnosed?
PCR, virus isolation, FA on tissues, paired sera
How is rhinopneumonitis treated?
No specific treatment - typically self-limiting
Monitor for secondary bacterial infections
How is rhinopneumonitis prevented and controlled?
Prevent introduction of new virus strains
Vaccination
T/F: The Rhino/flu vaccine provides short lived immunity that is not completely protective.
True
What is the etiologic agent of equine multinodular pulmonary fibrosis (EMPF)?
Equine herpesvirus 5 (EHV-5)
What do we currently know about the epidemiology of EMPF?
It is a disease of middle to older age horses
Everything else is unknown
What clinical signs are associated with EMPF?
Chronic progressive respiratory signs
Tachypnea, increased respiratory effort, dyspnea, intermittent fever and cough, weight loss
How is EMPF diagnosed?
Failure to respond to bronchodilators, antimicrobial therapy
Ultrasound and radiographic lesions
PCR
How is EMPF treated?
There is generally a poor response to treatment
What is the etiologic agent of rhinitis?
Equine rhinitis A virus (ERAV)
Equine rhinitis B virus (ERBV)
How is rhinitis transmitted?
Via respiratory secretions
What does infection of ERAV and ERBV result in (not rhinitis)?
Viremia with long-term fecal and urinary shedding
What are the clinical signs of ERAV infection?
Fever, anorexia, nasal discharge, coughing, pharyngitis, and swelling of the lymph nodes in the head and neck
What are the clinical signs of ERBV infection?
Mild - pharyngitis, respiratory signs, and depressed appeitte
Clinical signs caused by ERAV and ERBV is usually limited to how long?
2-3 days
How is rhinitis diagnosed?
PCR
Virus isolation
How is rhinitis treated?
No specific treatment, respiratory disease is typically self-limiting
Monitor for secondary bacterial infections
How is rhinitis prevented and controlled?
Prevent introduction of new virus strains
Vaccination
What is the lineage of Influenza virus that affects equine in the US?
Influenza A -> A/Equi 2 (H3N8) -> American lineage -> Florida clade (1 and 2)
T/F: Influenza is not endemic in the horse population and is in fact rare.
False - it is endemic
How is influenza transmitted?
Respiratory route - fomite, droplet, aerosol
Rapid spread of influenza is associated with what?
Outbreaks in naiive populations
What clinical signs are associated with influenza?
Fever, anorexia, depression
Harsh dry cough
Serous nasal discharge and lymphadenopathy
Conjunctivitis, corneal clouding
What age group of animals are most often affected by infleunza?
young animals > older
How is influenza diagnosed?
PCR, rapid ELISA, virus isolation and HI, and paired serum samples
How is influenza treated?
No specific treatment - usually self limiting
Monitor for secondary bacterial infections
How is influenza prevented and controlled?
quarantine clinical cases
Vaccination
What is the vaccination protocol for influenza?
Vaccinate based on risk - revaccinate at 6-12 month intervals based on this
What are the recommendations for the contents of the influenza vaccines?
They should contain both clade 1 and clade 2 viruses of the Florida sublineage
What is the etiology of equine viral arteritis?
Equine viral arteritis virus
Equine viral arteritis is an important differential for ______ respiratory disease.
Acute
What non respiratory signs are associated with equine viral arteritis?
Conjunctivitis, keratitis, palpebral edema, edema in the ventral and distal regions, weakness, loss of weight, and dehydraton
How is equine viral arteritis transmitted?
Either via respiratory secretions or venereal
Rhodococcus equi is a gram _____, facultative intracellular parasite.
positive
Where does R. equi live?
In the soil
Where can R. equi be found in asymptomatic young and adult horses?
In the intestinal tract and feces
How is R. equi transmitted?
Via inhalation of contaminated dust
What gene is important to the pathology of R. equi?
The vap A gene
What age group is commonly affected by R. equi?
Foals between 2-6 months of age
What clinical signs are associated with R. equi?
Respiratory disease predominates - cough, low grade fever initially, +/- mucopurulent nasal discharge, remain BAR until severe lung compromise
T/F: Subclinical R. equi infection is common.
True
How is R. equi definitively diagnosed?
TTW - culture or PCR
What can be used for a presumptive/subclinical diagnosis of R. equi?
Regular screening with ultrasound
Radiographs for clinical disease
How is R. equi treated?
Most subclinical will spontaneously resolve
When warranted - extended therapy for 2-12 weeks
How is R. equi prevented and controlled?
Dust reduction, rotating paddocks/pastures, move foals out of problem facilities Close monitoring via ultrasound Vaccination Hyperimmune plasma Chemoprophylaxis
T/F: There are 2 commercially available vaccines for R. equi available in the US right now.
False - that is Europe. There are none in the US
What is the etiologic agent of strangles?
Streptococcus equi ss equi
T/F: Strangles is highly contagious.
True
How is Strangles transmitted?
Via ingestion or inhalation of bacteria from lymph node discharge or respiratory secretions or contact with contaminated fomites
How does S. equi enter the system?
Via mucosa or tonsils
Convalescent S. equi carriers shed for how long?
> 4 weeks
Chronic carriers of S. equi result in what?
guttural pouch infections
What is the first clinical sign associated with strangles?
Sudden onset of fever followed by mucopurulent nasal discharge and inappetence
What clinical signs follow sudden onset of fever with strangles?
Acute swelling of the submandibular and retropharyngeal lymph nodes resulting in abscess formation
What are the rare sequelae of strangles?
Bastard strangles - metastatic abscessation
Purpura hemorrhagica
Myositis
How are acute cases of strangles diagnosed?
Presumptive diagnosis based on clinical signs
Definitive with culture or PCR
How are chronic strangles carriers diagnosed?
Culture or PCR of a guttural pouch wash
What does serology for SeM protein titers detect?
Previous infection
What does serology for SeM diagnose?
Bastard strangles and purpura hemorrhagica
What is serology for SeM protein titers used to determine?
the need for vaccination
What is the first step in the treatment of strangles?
Isolate to prevent spread
How are uncomplicated acute cases of strangles treated?
Supportive care only - soft feeds, hot pack, and drain abscesses
When is antibiotic therapy for treatment of strangles indicated?
In cases of bastard strangles
How are cases of purpura hemorrhagica treated?
Steroids
How are chronic carriers of strangles treated?
Flush the guttural pouches and topical and systemic antimicrobials
Generally, how is strangles prevented and controlled?
Quarantine all new arrivals for 3 weeks
Vaccination
How is strangles prevented and controlled in outbreak situations?
Quarantine premise for 3 weeks past the last clinical case
Monitor twice daily for fever
Separate feed and equipment for suspect cases
Chore from clean to dirty
Guttural pouch testing following outbreak to ID carriers
What are the most common organisms associated with guttural pouch infections?
S. equi, S. zoopidemicus
Aspergillus or other fungi are found
Guttural pouch infections can be due to failure of what?
Normal drainage
Guttural pouch infections are common sequelae to what?
Strangles
When can guttural pouch infections be fatal?
If corrosion into the internal carotid or branches of the external carotid artery occurs
What clinical signs are associated with guttural pouch infections?
Persistent mucopurulent drainage
Epistaxis due to damaged blood vessels
Damage to cranial nerves - dysphagia and facial nerve paralysis
How are guttural pouch infections diagnosed?
Endoscopy and culture +/- PCR
How are bacterial guttural pouch infections treated?
Flushing and antibiotics
How are fungal guttural pouch infections treated?
Flushing
Topical and systemic antifungal agents
May need to occlude the carotid artery proximal and distal to any lesions
