Chapter 7 - Viral and protozoal

Question 1

Histologically, pox lesions begin with ballooning degeneration of which cells?

Answer 1

The keratinocytes of the stratum spinosum

Question 2

Are poxviruses that affect horses zoonotic?

Answer 2

Yes

Question 3

What is the treatment for Molluscum contagiosum?

Answer 3

There is no successful treatment reported; lesions do not spontaneously regress.

Question 4

Which virus causes Equine Coital Exanthema?

Answer 4

Equine herpesvirus 3

Question 5

How is EH-3 transmitted?

Answer 5

Venereally
Insects
Fomites
Inhalation

Question 6

Pruritus with EH-3 can be demonstrated by which signs?

Answer 6

Tail rubbing, alopecia of the tail base

Question 7

Vesicular stomatitis can affect the oral mucosa and which other body site?

Answer 7

Lips
Prepuce and vulva
Udder and teats
Coronary band

Question 8

Which special stain is best able to demonstrate Leishmania amastigotes?

Answer 8

Giemsa

Question 9

Which Leishmania sp. causes disease in Europe?

Answer 9

L. infantum

Question 10

Is Leishmania pruritic?

Answer 10

No, not reportedly painful either

Question 11

What size are Leishmania amastigotes?

Answer 11

2-4 um

Question 12

In horses with leishmaniasis, how long does spontaneous remission take to occur?

Answer 12

3-5 months

Question 13

How many papillomaviruses are known in horses?

Answer 13

8

Question 14

Which equine papillomavirus causes classic viral papillomatosis?

Answer 14

EcPV1

head + extremities

Question 15

Which equine papillomavirus causes genital papillomas?

Answer 15

EcPV2

Also found in genital SCC!

Question 16

Which equine papillomavirus causes aural plaques?

Answer 16

EcPV 3-6

And EcPV 1

Question 17

Which equine papillomavirus causes generalised papillomatosis?

Answer 17

EcPV 7 and 8

Question 18

Which virus can cause fibrinoid necrosis of arterial walls and subsequent lymphocytic infiltration and leukocytoclasia?

Answer 18

Arterivirus (equine viral arteritis)

Question 19

What are the cutaneous signs of equine viral arteritis?

Answer 19

• Usually oedema in the hind legs, scrotum, prepuce, ventrum, periorbital areas.
• Less frequently oedema in sternum, mammary glands, shoulder, intermandibular space.
• Rarely urticaria or papules.

Question 20

With equine viral arteritis, do all infected animals show clinical signs?

Answer 20

Most infections are inapparent, especially those that occur in mares bred to persistently infected stallions.
Very young, very old and immunocompromised horses are in danger of developing severe forms of disease.

Question 21

Which bovine papilloma viruses are associated with equine sarcoids?

Answer 21

BPV-1 > BPV-2 (in Europe, BPV-2 predominant in US and NZ)

BPV-13

Question 22

How many genes do papilloma viruses have?

Answer 22

6 early, 2 late
Early genes encode proteins that possess transforming capability e.g. E5, E6, and E7, as well as proteins that regulate their replication and transcription e.g. E1, E2, and E4.

Question 23

Have EcPV vaccines be tried in horses?

Answer 23

Yes - using EcPV-1, may speed resolution of lesions

Question 24

Can EcPV-2 infection in horses by asymptomatic?

Answer 24

Yes - in 26% of horses in one study

Vertical transmission of EcPV-2 may occur

Question 25

Has malignant transformation of aural plaques to SCC been reported?

Answer 25

Yes

Question 26

How do you treat aural plaques?

Answer 26

• Do not spontaneously regress

- 5% imiquimod

Question 27

How are aural plaques transmitted?

Answer 27

Mode of transmission is unknow but Simulium spp. (black flies) may play a role

Question 28

Which EcPV are associated with SCC?

Answer 28

EcPV 2 - genital

EcPV 8 - inguinal

Question 29

Other than inguinal SCC, which other lesions have been associated with EcPV 8?

Answer 29

Viral plaques and generalised papillomas

• numerous
• trunk (ventral distribution) in particular

Question 30

Is there evidence to support an EcPV-2 vaccine in horses?

Answer 30

Yes - limited (EcPV-2 L1 VLP)

Question 31

Which virus causes molluscum contagiosum?

Answer 31

Molluscipox virus

Question 32

What are the clinical signs of molluscum contagiosum?

Answer 32

• Start focal then become widespread
• Chest, shoulders, neck and limbs most often affected
• 1-8mm papules, become alopecic with a powdery scale, some have soft white spicules,
• Coalesce to verrucous nodules/plaques
• Not pruritic/painful

Question 33

What are molluscum bodies?

Answer 33

Ovoid, eosinophilic, floccular intracytoplasmic inclusion bodies seen in keratinocytes
- become larger and more basophilic in the SG

Question 34

What are the clinical signs of equine herpes coital exanthema (EHV-3)?

Answer 34

• Papules, vesicles or pustules that form plaques and bullae
• Genitals and perineum
• Oedema, erosions, ulcers and crusts
• Pruritic, not painful
• Depigmentation at healed sites

Question 35

How is coital exanthema (EHV-3) spread?

Answer 35

• Coitus
• Insects
• Fomites
• Inhalation
• Embryo transfer

Question 36

Other than EHV-3, which herpes virus has been associated with skin lesions in horses?

Answer 36

EHV-1 and EHV-5 - papular, crusted and ulcerative dermatitis involving mucosae, periocular skin and muzzle

Question 37

What are the clinical signs of leishmaniasis in equids?

Answer 37

• Single or multiple papules or nodules that may ulcerate

- Located in the areas where sand flies commonly feed, that is, eyes, muzzle, neck, pinnae, scrotum and legs

Question 38

Can leishmaniasis spontaneously resolved in equids?

Answer 38

Yes - generally within 3-4 months

Question 39

What cause Dourine?

Answer 39

Trypanosoma equiperdum (protozoa)

Question 40

What are the clinical signs of dourine?

Answer 40

• Sexually transmitted
• Oedema of genitals and surrounding skin
• Papules that ulcerate
• Striking leukoderma
• Urticarial eruption (neck, chest, flanks, back) as later sign