Equine arteritis virus Flashcards
What’s a hallmark of this?
Persistent or prolonged infections; Has an RNA genome, enveloped
What does it do
Respiratory, abortion, death in neonates. PI stallions are reservoir
How can it be transmitted?
Aerosol (primary in acute), in utero, sexual, artificial insemination
How does it spread
Via monocytes and lymphocytes to regional lymphatics. After 3 days it is disseminated and attacks vascular epithelium and myocytes of blood vessels. Incubation is 3-14 days depending on exposure route. Acute phase lasts 2-9 days and has edema and hemorrhage
What are the clinical signs
Subclinical: fever, depression, inappetance, dependent edema, nasal discharge, dyspnea, urticarial reaction, leukopenia, possibly abortion. Fever and leukopenia most common. self limiting
When can abortions occur?
1-4 weeks after exposure and during the entire gestation period (3-10 months). risk in late acute or early convalescent phase.
What are the lesions?
Caused by vascular damage: edema, congestion, hemorrhage, vasculitis. Aborted fetuses partially autolyzed. Acute phase is vasculitis and the virus cannot be detected after 28 days in female
What is different in males?
Some of them are persistently infected in the repro epithelium, which leads to long term shedding of ineffective virus, can shed in semen. Testosterone dependent, may have short term fertility affected, carrier state has it persist in tissues but not shed in other secretions
Who can get it
Depends on virus, host, environmental factors. High level of neutralizing antibodies produced after exposure or vaccination for a few years. Very young or old and stressed or debilitated mostly get it. Higher in Standardbreds and Warmbloods
What is the diagnosis?
PCR on nasopharyngeal swabs or whole blood between 2-9 days so it’s in acute phase. Serology for after that. Stallions with more than 1:4 should be carriers. PCR on sperm rich part of ejaculate. Abortion: placental or fetal tissues PCR. Adult or foal death: lymphoreticular tissue PCR.
Treatment
Most make full recoveries no matter the treatment. No specific antiviral treatment. Early euthanasia of congenitally infected foals, cannot eliminate carrier state in stallions. MLV vx only after talking to state and federal animal health officials and only for sero negative animals in which testing and records are required. Can’t DIVA, at-risk vx.
