Exam 2: EHV and EIV

Question 1

What equine herpesviruses affect the respiratory tract?

Answer 1

EHV-1
EHV-4
EHV-5

Question 2

What is the host range for EHV-1

Answer 2

Horses
Camelids
Zebras
Alpacas

Question 3

What are the identified equine herpesviruses

Answer 3

Alphaherpesvirinae
Gammaherpesvirinae

Question 4

What is the host range for EHV-4

Answer 4

Only horses

Question 5

What is the hallmark of herpesvirus infections and epidemiology

Answer 5

Latency period
Modulate immunity/suppress immunity

Question 6

What type of stressful periods reactivate the virus

Answer 6

Horse shows
Transport
Pregnancy

Question 7

Where does EHV establish latency

Answer 7

Trigeminal ganglia

Question 8

What are the clinical signs of EHV-1 and EHV-4

Answer 8

Respiratory disease
EHM (EHV-1)
Abortion (EHV-1)
Foal death (EHV-1
Chorioretinopathy

Question 9

What are the differences in clinical symptoms between EHV-1 and EHV-4 respiratory disease

Answer 9

No clinical difference. Needs to do diagnostics

Question 10

Difference between young and old horses with clinical disease for EHV-1 and EHV-4

Answer 10

Respiratory disease in younger horses and neurological disease in older horses

Question 11

Where does EHV typically establish latency in the horse

Answer 11

Trigeminal ganglia

Question 12

How does EHV-1 spread

Answer 12

Primarily fomites
Nose-to-nose contact
Aerosol spread occurs but not primary

Question 13

What is an important pathogenesis for EHV-1

Answer 13

Cell-associated viremia

Question 14

Does EHV-4 cause viremia

Answer 14

No

Question 15

What are the characteristics of high-virulence strains of EHV

Answer 15

Neurological signs
Viremia
More endotheliotropic
Abortion

Question 16

How does the EHV mutation in the polymerase gene affect the functional properties of the mutant virus?

Answer 16

More likely to cause neurological symptoms
Longer duration of viremia

Question 17

Does the mutation automatically mean neurological disease for EHV

Answer 17

No, just more likely

Question 18

What factors determine if a horse gets neurological disease from EHV

Answer 18

Age
Health status
Breed
Gender (females more likely than males)

Question 19

What are the characteristics of less virulent strains of EHV

Answer 19

Decrease infection of endothelia
Rare abortions
Rare neurological disease

Question 20

What is the main difference in EHV-1 and EHV-4 and EIV pathogenesis

Answer 20

EHV-4 and EIV remain in the respiratory tract

Question 21

What diagnostic tests can you do with a nasal swab, blood, and serum sample for EHV

Answer 21

Paired serum sample. 4-fold increase from the first and second sample
Both EDTA and nasal swab samples for EHV-1
If only one sample-Swab sample would be the best (PCR to look for viral DNA)-Does not tell you if the amount of virus is infectious

Question 22

What test would you do on a swab to determine the strain or if the amount of virus that is being shed is infectious

Answer 22

Viral inhibition or viral isolation

Question 23

What is the disadvantage of serology for EHV

Answer 23

Serology-Need paired sample

Question 24

What are the advantages of viral isolation of EHV

Answer 24

Virus isolation and/or finding viral strain

Question 25

Why is timing important when considering diagnostic tests

Answer 25

Viral shedding vs antibody production

Question 26

What are the control strategies for EHV-1 and EHV-4

Answer 26

Biosecurity Medication Vaccination

Question 27

Which is the cornerstone control strategy for EHV

Answer 27

Biosecurity (isolation) For 28 days after last new infection

Question 28

How effective are vaccines and how commonly are they used in EHV

Answer 28

Protect a little against respiratory disease It does not protect against neurological disease Some protect against viral shedding No evidence that it prevents viremia No evidence it prevents EHM

Question 29

EHV-1 Empirical Control for Medical Treatment

Answer 29

Supportive therapy Antiviral drugs (valacyclovir) Anti-inflammatories (NSAIDs, steroids, aspirin, lidocaine) Heparin

Question 30

What is the EIV lineage/sublineage

Answer 30

H3N8 and by region/location

Question 31

What genera does EIV belong to

Answer 31

Type A

Question 32

What are the main components of EIV

Answer 32

Neuraminidase Hemagglutinin RNA virus Enveloped Glycoprotein which the antibody responds to Segmented genome-antigenic variation

Question 33

What the most common clinical signs in EIV

Answer 33

Anorexia/weight loss Fever Serous nasal discharge Mucoid purulent discharge Cough Lethargy

Question 34

How is EIV transmitted

Answer 34

Aerosol

Question 35

What are the steps in pathogenesis in EIV

Answer 35

Respiratory epithelium Cell-to-cell transfer Stays restricted to the respiratory tract

Question 36

What are the complications with EIV

Answer 36

Secondary bacterial infections Bronchopneumonia

Question 37

What sample would be taken for EIV

Answer 37

Nasal discharge Serum sample: Paired sample->Looking for antibodies

Question 38

What type of infection is EIV

Answer 38

Acute

Question 39

What is the most important aspect of EIV control

Answer 39

Vaccine

Question 40

What types of EIV vaccines are available

Answer 40

Modified live (MLV) Inactivated Recombinant

Question 41

What is the most important aspect of EHV control

Answer 41

Biosecurity

Question 42

What is a disadvantage of MLV vaccine in EIV

Answer 42

MLV could cause pathogenicity, stray away from in immunocompromised patients

Question 43

What is an important aspect of recombinant vaccine in EIV

Answer 43

Recombinant could cause a diva vaccine, which differentiates from natural infection in a horse or horses that are infected by vaccine

Question 44

What are the problems with EIV

Answer 44

Antigenic shift Antigenic drift (gradual) Viruses change