Canine and equine herpes

Question 1

What are the properties of these viruses?

Answer 1

Latency, lifelong infections, unstable out of host

Question 2

How is canine spread?

Answer 2

Oronasal secretions or in utero to puppies or neonates

Question 3

Which animals are usually affected?

Answer 3

Puppies less than 3 weeks or fetuses, will have sublinical, lifelong latent infections with 100% mortality early in affected litters

Question 4

What happens when older puppies or dogs are infected?

Answer 4

replicates in surface cells of the nasal passages, pharynx, tonsils

Question 5

What happens when neonates and immunocompromised dogs are infected?

Answer 5

Viremia and infection of varying visceral organs

Question 6

What about the clinical disease in dogs?

Answer 6

Sudden death most common, no fever or leukocytosis. In older dogs the disease is subclinical.

Question 7

What are the lesions?

Answer 7

Disseminated focal necrosis and hemorrhage; mostly in renal cortex and makes the kidneys look mottled.

Question 8

Diagnosis and prevention

Answer 8

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.

Question 9

What are the subtypes of equine herpesvirus?

Answer 9

EHV-1: respiratory, abortions, neuro, neonatal death. EHV-4: mostly respiratory

Question 10

How prevalent is equine herpesvirus?

Answer 10

Worldwide, horse is reservoir and most latently infected with 1.

Question 11

How is the outcome?

Answer 11

Depends on virus strain, immune status, pregnancy, age

Question 12

What is the pathogenesis?

Answer 12

oronasal exposure leads to infections in the URT epithelium, 2-10 day incubation period that leads to clinical or subclinical dz

Question 13

What are the differences in replication?

Answer 13

EHV1: cell-associated viremia and infects vascular epithelium of lungs, nasal passages, thyroid, adrenal glands. EHV4 restricted to respiratory and lymph nodes

Question 14

How does each strain affect fetuses?

Answer 14

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

Question 15

What is the respiratory part of equine?

Answer 15

Both result in high fever (1 being biphasic), serous nasal discharge.

Question 16

What is the neuro part?

Answer 16

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

Question 17

How do you diagnose?

Answer 17

Respiratory: PCR from nasopharyngeal swabs; neuro: PCR from nasal secretions; abortion: PCR, IHC from aborted fetus

Question 18

What is the treatment?

Answer 18

Supportive, most foals with EHV1 die. Those with neuro signs only have good prognosis if moving or only recumbent for a couple of days

Question 19

Prevention of equine

Answer 19

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

Question 20

Details on avian herpesvirus

Answer 20

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