LEC 11 - Herpesvirus I

Question 1

What genomic viruses are herpes viruses?

Answer 1

DNA

Question 2

What is the general structure of the herpes virus?

Answer 2

Enveloped

Question 3

How does the herpes virus attach to the host cell?

Answer 3

Glycoprotein

Question 4

What happens one the herpes virus is attached to the host cell?

Answer 4

Viral envelope fuses with plasma membrane

Nucleocapisid enters cytoplasm

Transported to nucleus

Question 5

How is the herpes virus released?

Answer 5

budding from nuclear membrane

Accumulate in vacuoles

Released by cytolysis

Question 6

What is seen upon histological exams when herpesvirus is present?

Answer 6

Rapid cyopathic effect

– and –

Nuclear inclusion bodies

Question 7

What is the transcription method of herpesvirus?

Answer 7

Mucosal surface contact

– or –

Droplet transmission

Fomites

Question 8

How is the herpes virus present in the body?

Answer 8

Establishes permanent latency

Maintained as episome

Question 9

What is occurring during latency of the herpes virus?

Answer 9

Few genes expressed

Infection truly hidden

Question 10

What causes reactivation of the herpes virus?

Answer 10

Stress -

Transport

Crowding

Boarding

Weather

Question 11

How can you get false positives in herpes testing?

Answer 11

Use of rapid nucleic acid tests (PCR)

Latency + High sensitivity leads to false positives

Question 12

What does BHV-1 cause?

Answer 12

Rhinotracheitits

Infectious pustular vulvovaginitis

Conjunctivitis

Abortion

Enteritis

Question 13

What can BHV-1 lead to in feedlots?

Answer 13

Complicated secondary infections - Bovine respiratory disease

= Shipping fever

Question 14

What are the clinical signs of BHV-1?

Answer 14

High temperature

Coughing

Eye/nasal discharge

Weight loss

Abortion

Question 15

What are the risk factors for a BHV-1 outbreak?

Answer 15

Large herds/high density

Presence of dairy cattle

Input of new stock

Visitors

Question 16

When can BHV-1 be most problemative?

Answer 16

Naive herds

Question 17

What are the preventative mechanisms for BHV-1?

Answer 17

Keep herds closed + Vaccination

Live attenuated + Inactivated vaccines avalible

Question 18

what is the problem with attenuated vaccines for BHV-1?

Answer 18

Potentially abortigenic + pose risk to unvaccinated animals

Question 19

What are the pros and cons of attenuated BHV-1 vaccines?

Answer 19

Work fast

Useful for controlling outbreaks

Allow latency establishment + potential furture virus reactivation

Question 20

What are the pros and cons of inactivated BHV-1 vaccines?

Answer 20

OK for pregnant animals

Do not create immunosuppression

Reduce latency shedding of virus

Question 21

What does OHV-2 cause?

Answer 21

Malignant catarrhal fever in cattle or bison

Question 22

What is the source of OHV-2?

Answer 22

Recently lambed sheep or goats

Question 23

What symptoms ares seen with malignant catarrhal fever?

Answer 23

High fever

Depression

nasal/ocular discharges

extensive ulcerations in oral cavity

Corneal opacity

Question 24

What does EHV-1,4 cause?

Answer 24

Acute febrile respiratory disease

Rhinopharyngitis

Tracheobronchitis

Question 25

Which EHV is most common with annual outbreaks in foals?

Answer 25

EHV-4

Question 26

What is important to note about EHV-1?

Answer 26

Neuropathic Increasing in virulence + prevalence = Emerging infection

Question 27

What specific diseases processes do EHV-1 cause?

Answer 27

Abortion in horses Respiratory disease Encephalomyelitis

Question 28

What does EHV-1 do in the blood stream?

Answer 28

Produce viremia Focus on vascular endothelium of nasal mucosa + lungs + CNS Neuropathogenic strinas produce much high viremic loads (less gross pathology)

Question 29

What are the risk factors for an EHV-1 infection?

Answer 29

Age Stabled vs pastured High traffic of animals + humans Frequant transport Season

Question 30

What seasons are EHV-1 infections most common?

Answer 30

Late Autumn - Winter - Spring

Question 31

What is done to control the spread of EHV-1?

Answer 31

Cease transport Seperate/Quarantine diseased stock Sanitary precautions for handlers Regular serial vaccinatiosn

Question 32

How long should a horse be quarantined for EHV-1?

Answer 32

21 to 28 days

Question 33

Where do EHV-4 infections target?

Answer 33

Respiratory epithelium Associated with lymph nodes

Question 34

What is the most common disease process caused by EHV-4?

Answer 34

Foals infected early Acute respiratory disease (over 2 months old)

Question 35

Why do foals tend to become infected with EHV-4 after 2 months of age?

Answer 35

Passive immunity from mare declines

Question 36

What is the therapy for EHV-4?

Answer 36

Rest Nursing care + anti-pyretics Valacyclovir

Question 37

What does gallid herpesvirus 1 cause in chickens/

Answer 37

Infectious laryngotracheitis

Question 38

At what age do chickens tend to get infectious laryngotracheitis?

Answer 38

4 to 18 months of age

Question 39

What are the common symptoms of infectious laryngotracheitis?

Answer 39

Coughing Sneezing Nasal/Ocular discharge

Question 40

What do you see in chickens with infectious laryngotracheitis?

Answer 40

Pump handle respiration (neck raised + head extened during inspiration)

Question 41

How does a flock of chickens acquire GHV-1?

Answer 41

Introduced by carrier birds

Question 42

How is GHV-1 spread?

Answer 42

Aerosol transmission Fomite transmission

Question 43

How is GHV-1 diagnosed?

Answer 43

PCR Detection of virus antigens in tissues/smears

Question 44

Why must caution be used when using the GHV-1 vaccines?

Answer 44

Attenuated vaccines stop disease but not that caused by virulent strains Latency established - infection from carrier animals is possible

Question 45

What does GHV-2 cause?

Answer 45

Marek's disease

Question 46

What are the forms of Marek's disease?

Answer 46

Neural Visceral Ocular

Question 47

What does GHV-2 target?

Answer 47

Proliferation of T cells - causes several different syndromes

Question 48

What occurs in the neural form of Marek's disease?

Answer 48

Tumors in the nerves + brain = Asymmetric weakness/paralysis of wings + legs

Question 49

What occurs in the visceral form of marek's disease?

Answer 49

Tumors of internal organs (Liver + Spleen + Gonads + Feather follicles + Heart + Kidney)

Question 50

What is death normally caused by with Marek's disease?

Answer 50

Dehydration -- or -- Starvation

Question 51

What can Marek's disease lead to?

Answer 51

Progressive lymphoproliferative disease Lymphoma with early pahse incoordination sign + wing dropping of head/neck

Question 52

What is seen in acute disease with Marek's?

Answer 52

Explosive outbreaks of ataxia + paralysis in young Significant mortality

Question 53

What is skin leucosis caused by GHV-2?

Answer 53

Cutaneous diease signs where non-feathered areas become reddened with nodular lesions at feather follicles

Question 54

What does GHV-2 do to the eyes?

Answer 54

Ocular lymphomatosis Transformed lymphocytes migrate to eye - produce graying with irregular eccentric pupil + blindness

Question 55

How long can the Marek's virus remain stable outside the body?

Answer 55

Weeks

Question 56

When are chickens most susceptible to Marek's disease?

Answer 56

Early in life

Question 57

What is seen on necropsy that suggests Marek's disease?

Answer 57

Unilateral enlargement of peripheral nerve trunks

Question 58

How is Marek's disease controlled?

Answer 58

Vaccination

Question 59

What is the GHV-2 vaccine made out of?

Answer 59

Weak Marek's virus strain + turkey herpes virus Cell-associated vaccine preps to vaccinate chicks with maternal antibodies

Question 60

When are vaccinates done for GHV-2?

Answer 60

in ovo

Question 61

What does the vaccinations for GHV-2 do in reagards to disease control?

Answer 61

Does not prevent infection Makes the clinical disease less