PATHOLOGY - Gastrointestinal Viral Infections

Question 1

What are the two key parvoviral infections in veterinary medicine?

Answer 1

Canine parvovirus 2 (CPV-2)
Feline panleukopenia virus (FPV)

Question 2

What is the pathogenesis of parvoviral infection?

Answer 2

These viruses undergo oronasal exposure and are taken up into the tonsils and Peyer’s patches where they will invade and undergo viral replication within the lymphocytes. The virus will undergo systemic dissemination either within the lymphocytes or as free viral particles (cell-free viraemia) and travel to the crypt enterocytes where they will invade and undergo viral replication, resulting in necrosis. These viral particles will also disseminate into the bone marrow resulting in hypocellularity and necrosis. Parvoviruses have a tissue tropism for rapidly dividing cells such as intestinal epithelial cells and haematopoietic cells, resulting in intestinal mucosal damage and neutropenia which increase the risk of translocation of enteric bacteria and sepsis

Question 3

Which intestinal lesions result due to the parvoviruses?

Answer 3

Haemorrhagic-necrotising enteritis
Fibrino-necrotising enteritis and exudate

Question 4

What are the histological features of the parvoviruses?

Answer 4

Necrosis of the crypt epithelial cells
Crypt dilatation with necrotic debris
Villous atrophy
Necrosis of the lymphoid tissue in the Peyer’s patches
Intranuclear inclusion bodies (only in early disease)
Epithelial regeneration (only in late disease)

Question 5

Which extra-intestinal lesions result due to parvoviral infection in the dog?

Answer 5

Bone marrow hypocellularity and necrosis
Lymphocytolysis (lymphopenia)
Necrotising myocarditis
Generalised necrosis of the organs

Question 6

Which signalement is susceptible to generalised necrosis of the organs due to parvoviral infection?

Answer 6

Neonates

Question 7

Which extra-intestinal lesions result due to parvoviral infection in the cat?

Answer 7

Bone marrow hypocellularity and necrosis
Lymphocytolysis (lymphopenia)
Cerebellar hypoplasia

Question 8

Which region of the intestine is specifically targeted by coronavirus?

Answer 8

Tips of the villi

Question 9

List examples of coronaviruses

Answer 9

Porcine epidemic diarrhoea virus (PEDV)
Transmissible gastroenteritis virus (TGEV)
Bovine coronavirus (BCoV)
Equine coronavrus (ECoV)

Question 10

Which signalement is typically affected by porcine epidemic diarrhoea virus (PEDV)?

Answer 10

Suckling piglets

Question 11

Which signalement is typically affected by transmissible gastroenteritis virus (TGEV)?

Answer 11

Suckling piglets

Question 12

What histological lesions result due to porcine epidemic diarrhoea virus (PEDV) and transmissible gastroenteritis virus (TGEV)?

Answer 12

Intestinal villous blunting and fusion

Question 13

Which signalement is typicaly affected by bovine coronavirus (BCoV)?

Answer 13

Neonatal calves

Question 14

Which disease process is caused by bovine coronavirus (BCoV) in adult cattle?

Answer 14

Winter dysentry

Question 15

Which intestinal lesions result due to equine coronavirus (ECoV)?

Answer 15

Red discolouration of the intestinal mucosa
Ulcerative enteritis
Red tinged intestinal contents

Question 16

Which histological lesions result due to equine coronavirus (ECoV)?

Answer 16

Necrotising enteritis
Villous blunting and fusion
Neutrophilic and fibrinous exudate
Crypt necrosis and abscessation
Microthrombosis
Haemorrhage
Intranuclear inclusion bodies (rare for coronaviruses)

Question 17

Which histological lesions result due to rotavirus?

Answer 17

Villous atrophy and fusion

Question 18

Which disease is associated with equine adenovirus 1 (EAdV-1)?

Answer 18

Upper respiratory tract infections

Question 19

Which disease is associated with equine adenovirus 2 (EAdV-2)?

Answer 19

Gastrointestinal tract infections

Question 20

Which gross lesions result due to equine adenovirus 2 (EAdV-2)?

Answer 20

Necrosis and ulceration of distal oesophagus
Necrosis and ulceration of squamous gastric mucosa
Soft to semi-fluid filled ingesta
Villous atrophy of the small intestine

Question 21

Which histological lesions result due to equine adenovirus 2 (EAdV-2)?

Answer 21

Intranuclear inclusion bodies of the small intestine
Villous atrophy of the small intestine

Question 22

What are the potential causes of equine grass sickness?

Answer 22

Oxidative stress
Fungal toxins
Weather changes
Clostridium botulinum C toxin

Question 23

Why is clostridium botulinum C toxin a controversial potential cause of equine grass sickness?

Answer 23

Clostridium botulinum C toxin is a controversial cause of equine grass sickness as it could be causal but could also be a manifestation of secondary bacterial overgrowth

Question 24

What are the risk factors for equine grass sickness?

Answer 24

Pasture grazing
Recent move to new pasture
Horses aged 2 - 7
Spring to early summer
High metal concentrations in the herbage
High abundance of buttercups
Cool, dry weather with irregular frost

Question 25

What are the gross pathological lesions resulting from acute/subacute equine grass sickness?

Answer 25

Gastric distension with pale to tan mucinous fluid Gastric rupture Excess intestinal fluid contents Large intestinal impaction with dry, possibly blackened contents Small colon impaction with small, dry, possibly blackened contents

Question 26

What are the gross pathological lesions resulting from chronic equine grass sickness?

Answer 26

Marked decrease in alimentary contents Hypertrophy of the intestinal musculature

Question 27

What are the key histological lesions resulting from equine grass sickness?

Answer 27

Chromatolysis with dispersion and loss of nissl substance Neuronal cytoplasmic swelling and vacuolation Peripheral displacement of nuclei of affected neurones | There are required for histopathological diagnosis

Question 28

What is nissl substance?

Answer 28

Nissl substance is the neuronal rough endoplasmic reticulum