Equine infectious viral respiratory disease Flashcards
What are causes of equine infectious viral respiratory disease?
Adenovirus Influenza Equine herpes virus 1&4 Rhinovirus Equine viral arteritis African horse sickness
Adenovirus is usually a cause of mild or subclinical viral respiratory disease. In which animals can adenovirus pose a serious problem? Why?
Arab foals
As they have SCID (severe combined immunodeficiency)
Arab foals
What family are the influenza viruses in? What are the subtypes based on?
Orthomyxoviridae
Different surface antigens
What are the clinical signs of influenza?
Pyrexia Nasal discharge (watery then mucopurulent) Coughing Tachypnoea Inappetance Retropharyngeal lymphadenopathy Weight loss
How long is the incubation period for influenza?
24-48 hrs
Which animals are most at risk for influenza?
Young horses in large groups
Older, stressed, immunosuppressed
What is the morbidity/mortality of influenza?
High morbidity Low mortality (except foals)
Describe the pathogenesis of influenza
Subclinical carriers shed and infect others
Inhaled virus attaches to respiratory mucosa and spreads along RT
Damages epithelium and cilia (leads to secondary infections)
How is influenza diagnosed?
Clinical signs
Rapid spread
Nasal/trachel swab for virus
What is the treatment for influenza?
Symptomatic - NSAIDs, anitmicrobials
Antiviral drugs
Is there a vaccination for influenza? What cause it target? What are the issues with it?
Yes - targets surface antigens
Can cause fever for few days
Problems with antigenic drift
What are the differences between equine herpes virus 1 and 4?
4 = respiratory only 1 = respiratory, neurological, abortion
Which horses are mainly affected by EHV?
Young (1-3)
How is EHV spread?
Inhaled
Attaches and replicates on mucosal surfaces
What is the incubation of EHV?
3-7 days (up to 3 weeks)
What are the host-pathogenic interatctions?
Enzootic (endemic)
Infection in early life
Latent infection and intermittent shedding for up to 3 weeks
Recovered horses present no greater risk
What are the symptoms of EHV?
Biphasic fever Lethargy and inappetance Oedema Hyperaemia of mucosa Serous nasal discharge Some cases have coughing
What is the prognosis of EHV?
Usually always fatal in young foals
Older foals survive but suffer from other diseases
Yearlings and adults - have recurrence of latent infection and less severe disease
How is EHV diagnosed?
Virus isolation (nasal swabs, tracheal wash, PCR and serology)
Is there a vaccination for EHV? When are they given?
Yes - modified lived and dead available
1st at 5 months, second 4-6 weeks later with boosters every 6 months
Pregnant mares at 5,7 and 9 months
What type of virus is the equine rhinovirus?
Picornavirus
Describe equine rhinovirus
Mild respiratory disease
Lasts 3-5 days duration
No vaccination
What are the symptoms of equine rhinovirus?
Fever Rapid spread Anorexia Nasal discharge Pharyngeal lymphoid hyperplasia
What family is equine viral arteritis from?
Arteriviridae
