Canine and equine herpes Flashcards
What are the properties of these viruses?
Latency, lifelong infections, unstable out of host
How is canine spread?
Oronasal secretions or in utero to puppies or neonates
Which animals are usually affected?
Puppies less than 3 weeks or fetuses, will have sublinical, lifelong latent infections with 100% mortality early in affected litters
What happens when older puppies or dogs are infected?
replicates in surface cells of the nasal passages, pharynx, tonsils
What happens when neonates and immunocompromised dogs are infected?
Viremia and infection of varying visceral organs
What about the clinical disease in dogs?
Sudden death most common, no fever or leukocytosis. In older dogs the disease is subclinical.
What are the lesions?
Disseminated focal necrosis and hemorrhage; mostly in renal cortex and makes the kidneys look mottled.
Diagnosis and prevention
PCR on fresh tissue. No vaccine and therapy not helpful when systemic, otherwise use antiviral ophthalmic ointment. Isolate pregnant ones from others during the last 3 weeks of gestation and first 3 weeks of postpartum.
What are the subtypes of equine herpesvirus?
EHV-1: respiratory, abortions, neuro, neonatal death. EHV-4: mostly respiratory
How prevalent is equine herpesvirus?
Worldwide, horse is reservoir and most latently infected with 1.
How is the outcome?
Depends on virus strain, immune status, pregnancy, age
What is the pathogenesis?
oronasal exposure leads to infections in the URT epithelium, 2-10 day incubation period that leads to clinical or subclinical dz
What are the differences in replication?
EHV1: cell-associated viremia and infects vascular epithelium of lungs, nasal passages, thyroid, adrenal glands. EHV4 restricted to respiratory and lymph nodes
How does each strain affect fetuses?
EHV1 mares abort up to 12 weeks after infection (late gestation) with fetuses fresh or minimally autolyzed. Foals may also have pneumonitis. Conception after is not affected. EHV4 rarely includes abortions
What is the respiratory part of equine?
Both result in high fever (1 being biphasic), serous nasal discharge.
What is the neuro part?
neuropathic strains of 1, emerging disease that may be reportable in some states. Equine herpesviral myeloencephaly include mild ataxia, posterior paresis or paralysis, urinary incontinence. Minimal evidence of hemorrhage in meninges
How do you diagnose?
Respiratory: PCR from nasopharyngeal swabs; neuro: PCR from nasal secretions; abortion: PCR, IHC from aborted fetus
What is the treatment?
Supportive, most foals with EHV1 die. Those with neuro signs only have good prognosis if moving or only recumbent for a couple of days
Prevention of equine
Minimize exposure, isolate affected horses, quarantine. For both 1 and 4, use inactivated vx as well as just for EHV-1 abortion. For EHV1 resp, use MLV. No vx for neuro and only risk based vx
Details on avian herpesvirus
clinical signs are severe dyspnea, gasping, hemorrhagic exudate. Marek’s disease is one and includes peripheral nerve enlargement, ubiquitous, characteristic lymphoid neoplasia, paralysis of legs or wings. control with vx
