C19 pt 2

Question 1

Bovine papular stomatitis
- genus, family, relative
- clinical significance
- age, signalment
- signs
- lesions
- humans
- differentials

Answer 1

o Genus Parapoxvirus, Family Poxviridae, relative
of pseudocowpox
o Usually not clinically significant but must rule out
similar diseases
o Often seen in calves with failure of passive
transfer or immunosuppressed adults o Does not form vesicles
o Individual lesions heal within a week o Potentially zoonotic
o Differentials: BVD, FMD, infectious bovine rhinotracheitis
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- Round, erythematous papules on nose and mouth
- Elevated at first but become necrotic and may slough to leave ulcers

Question 2

Contagious pustular dermatitis (orf)
- species
- morbidity, mortality
- lesion, development
- humans

Answer 2

o Similar to papular stomatitis but specific to small ruminants, more exudative
o High morbidity and may cause death in suckling lambs/kids
o Proliferative scabby lesions on lips, face, udder, feet; may extend into mouth
o Starts as papules that become pustules, rupture, and form scabs
o Potentially zoonotic

Question 3

Coronaviruses
- environmental survival
- tropism, replication site
- lesions
- signs
- regeneration and recovery

Answer 3

• All are enveloped ssRNA viruses (poor survival outside host)
• Infect and replicate in apical cytoplasm of enterocytes on tips and sides of villi
  o Exfoliation of infected cells causes villus atrophy and fusion
  o Malabsorptive diarrhea due to defective lipid absorption (even before cells slough)
  o Crypt hyperplasia allows regeneration in 2-3 days
  o Recovery in 4-6 days if survive dehydration and electrolyte imbalances

Question 4

Coronaviruses of swine
- signs in suckling pigs
- seasonality
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- 3 forms
> signs, morbidity, mortality
> neonates
> enzootic herd signs
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- signs, PM lesions

Answer 4

• All cause vomiting, diarrhea, and wasting in suckling pigs, mostly due to enteritis
• Problem in winter because enveloped virus can’t survive sun or heat
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• Transmissible gastroenteritis virus (TGEV)
  o Clinical disease in any age, high morbidity in naïve herds but milder in adults
  o Severe diarrhea and nearly 100% mortality in piglets <10-14 days old
  o Recall neonates can’t regenerate enterocytes as effectively
  o Enzootic herds: high mortality in gilt litters, low mortality but diarrhea and wasting in
  weaned pigs with waning colostral immunity
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• Porcine epidemic diarrhea virus (PED): clinically identical to TGEV
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• Porcine deltacoronavirus: similar to TGEV but clinically milder
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• Undifferentiated diarrhea
• Lymphatics are empty due to malabsorption - Flaccid, thin-walled intestines with liquid contents
• Cold, dehydrated and wasted piglets with fecal soiling due to diarrhea

Question 5

Coronaviruses in cattle
- Diarrhea in neonates
> common? other pathogens?
- tropism
- problems, recovery
- lesions?

Answer 5

o Common, occurs alone or with other agents (especially severe if with BVD)
o Infects enterocytes of SI and colon, causing severe diarrhea
o Often also damages Peyer’s patches, may cause respiratory disease
o Calves will still eat, recover in 5-6 days if they survive dehydration and electrolyte
imbalances
- gross lesion nonspecific

Question 6

Coronaviruses in cattle
Diarrhea in neonates differentials
by age

Answer 6

<7 days: E. coli

5-15 days: Rotavirus, cryptosporidiosis, infectious bovine rhinotracheitis Salmonella, BVD less likely

Question 7

Coronaviruses in cattle
* Winter dysentery
- morbidity, mortality, age
- usual suspect
- lesions and signs

Answer 7

o High morbidity, low mortality syndrome of adult cattle
o Usually young, postpartum dairy cows, can occur in summer too
o Signs mostly related to colon lesions: bloody diarrhea, milk drop, anorexia, nasolacrimal discharge +/- cough
- Gross: linear congestion/hemorrhage of colon with bloody contents

Question 8

Feline enteric coronavirus
- transmission
- signs, age
- FIP connection

Answer 8

o Feco-oral infection, ubiquitous and often subclinical
o Sometimes causes mild to moderate diarrhea in kittens
o ~13% never clear infection and are lifelong carriers – these can progress to FIP

Question 9

Feline infectious peritonitis (FIP)
- signalment
- enteric connection
- cells, when disease occurs
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- lesions, forms
> which more common, Ddx
> fatality

Answer 9

o Sporadic disease, often young males, purebreds
o De novo mutation from enteric form in every affected cat
o Replicates in macrophages – disease only occurs if cell-mediated response fails
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o Lesions exist on a continuum depending on dominant immune response mechanism
o Both forms have vasculitis and pyogranulomatous inflammation
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WET FIP
- Antibody-mediated Type III hypersensitivity
o More common, rapid, fatal clinical course
o Ocular and CNS lesions uncommon
o Main differential: bacterial peritonitis
- Marked abdominal distention
- Clear yellow fluid, fibrin/pyogranulomas on serosa
- Enlarged lymph nodes
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DRY FIP
- Cell-mediated
o More chronic progression
o May have ocular, CNS, renal, hepatic, or pancreatic lesions and/or colitis
o Differentials: lymphoma, steatitis (look for virus in lesions via PCR, IHC)
- Serosal pyogranulomas without effusion
- Can develop hydrocephalus if pyogranulomas obstruct CSF

Question 10

Rotaviruses
- family, serogroups, most important
- usual clinical signs
- environmental survival
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- pathogenesis, cells infected
- adult vs young
- syncytia?
- diarrhea
- Infected enterocytes also produce….
- timing, recovery
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Always consider when??

Answer 10

• Family Reoviridae, 7 serogroups but group A is most common and important
  o Infections are often subclinical
• Resistant to environmental degradation (unlike coronaviruses)
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• Infect enterocytes on tips and sides of distal 50-66% of villi
  o Fewer receptors used for virus entry in adults (disease usually in young animals)
  o Infected cells can fuse (syncytia) and slough readily
  o Malabsorptive diarrhea plus secretory enterotoxin
  o Infected enterocytes also produce vasoactive compound that causes villus ischemia
  o Virus is most prevalent at 18-24 hours post-infection and declines by 3-4 days
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  Always consider rotavirus in diarrhea of young animals, especially with villus atrophy!

Question 11

Rotaviruses in cattle
- age
- presentation
- gross lesion

Answer 11

• Mostly neonates (beef and dairy), often with other pathogens
• Most common between 4-5 days and 2-3 weeks old
• Milder than coronavirus and E. coli
• 1-3 days prepatent, 2-5 days of diarrhea
• Gross lesion: undifferentiated diarrhea

Question 12

Rotaviruses in swine
- how common, presentation
- age, risk factors
- signs

Answer 12

• Common, often subclinical or with other pathogens
• Usually piglets with failure of passive transfer or post-weaning
• ‘White scours’ (steatorrhea) in 2-8 week old pigs
• Clinical signs, gross findings similar to TGEV but milder

Question 13

Rotavirus in lambs, foals, and puppies
- age, mortality

Answer 13

• Also common in neonatal lambs, foals <3-4 months old (low mortality)
• May be fatal in puppies <1-2 weeks old

Question 14

Parvoviruses
- genus, environmental survival
- replication, cells affected
- signs depend on
- damages what tissues

Answer 14

• Genus Parvovirus, small, nonenveloped, ssDNA viruses – hardy in environment
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• Virus replication can only happen during mitosis – affects mitotically active tissues (crypts) o The more mitotic activity, the worse the damage
  o Signs depend on severity of crypt damage (can ulcerate if really severe)
  o Also damages bone marrow, lymphoid tissue

Question 15

Parvoviruses
Canine parvovirus 2 and mink enteritis virus are strains of …..
- what confers host range variability?

Answer 15

• Canine parvovirus 2 and mink enteritis virus are strains of feline panleukopenia
  o Biologically distinct, different host cell ranges and virulence
  o Variation in receptors used to enter cells confers host range variability

Question 16

Parvoviruses
- pathogenesis
- when can be blocked?
- destroys what?
- when is max damage

Answer 16

• Infect tonsils and Peyer’s patches
  > Dissemination via lymph, viremia
  ! Blocked when antibodies produced (6-9 days) !
  > Replication in and destruction of crypts > Does NOT spread via gut lumen!
  > Maximum damage 5-9 days post infection
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  5-7 days post infection:
  > Loss of absorptive surface
  > Exudate from erosion
  > Mortality due to dehydration, secondary infections

Question 17

Parvoviruses
- usual presentation
- when would we see clinical signs
- symtptoms and problems
- marrow damage problems, recovery
- survival?
- present in feces until?

Answer 17

• Most infected animals do not develop disease
  o If it occurs, usually seen in the late viremic phase
• Diarrhea and vomiting contribute to dehydration, sometimes anemia
• Bone marrow damage leads to lymphopenia
  o May be paired with transient neutropenia (cats > dogs), both together = leukopenia
  o Restored within 2-5 days in survivors
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• If the animal survives acute disease and enough crypt cells remain, will recover
  o Viral antigen present in feces until neutralizing antibodies form at 6-9 days

Question 18

Parvoviruses
* Feline panleukopenia (FPV)
- species
- age
- signs
- fluids?
- gross / histo lesions?
- Dx confirmation?

Answer 18

o Infects all felids, mink, and raccoons; common and usually subclinical in cats
o Disease usually in kittens after passive transfer wanes
o Fever, depression, anorexia, vomiting, diarrhea, dehydration, sometimes anemia
o May see edema due to hypoproteinemia if IV fluids administered
o Often no gross lesions in GI tract, patchy histologic lesions (collect lots of pieces!)
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- If lucky: segmental reddening
- Diphtheritic membranes over Peyer’s patches
- Colon lesions present in half of cases but milder than SI
- Confirm diagnosis based on histology +/- antigen
- Cerebellar hypoplasia in fetal infections

Question 19

Parvoviruses
* Canine parvovirus 2 (CPV2)
- origins
- species
- history, age affected
- signs, fatality, recovery
- lesions
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- rare lesions in puppies of naive bitches

Answer 19

o Mutated FPV-like virus, likely arose in wild canids
o Faster evolution than FPV, some variants infect cats, skunks, raccoons
o Explosive spread through dogs of all ages in 1978, now mostly a disease of puppies
with waning maternal immunity
o Anorexia, lethargy, vomiting, malodourous diarrhea +/- blood, leukopenia
o Either die of dehydration or begin to recover in 2-3 days
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- Segmental reddening, often with serosal fibrin (ground glass)
- Like FPV, need histology from multiple areas
- May see evidence of sepsis in lungs
- Fluid gut contents, +/- fibrin
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o Nonsuppurative myocarditis in <15 day old puppies of naïve bitches (rare, does not
usually occur in older puppies with enteric disease)

Question 20

Canine parvovirus 2 Ddx

Answer 20

o Differentials: coronavirus, shock gut, coagulopathy, distemper (lymphoid involution)

Question 21

Aspergillus and zygomycetes
- sequel to…
- what do they require to infect?
- signs?
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- Dx
- lesions

Answer 21

o Common sequel to mucosal damage of any cause, anywhere in the GI tract
o Require
1) high challenge,
2) disrupted normal flora, or
3) lowered resistance
o Variable clinical signs, sometimes allows systemic spread
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Confirm via culture (tricky) and genetic identification
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- Hemorrhagic/infarctive lesions: Mucorales and Aspergillus spp.
> Most common post-rumen acidosis in cattle
> Tend to invade veins (thrombosis and venous infarction)
> May reach liver via portal vein
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- Granulomatous lesions – main differential?
- PAS+ hyphae may be present in mesenteric LN granulomas of healthy cattle

Question 22

Candidiasis (mostly Candida albicans)
- what is it? type of infection
- risk factors
- prefers what tissue
- damage
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pig, cattle, horse, poultry signs

Answer 22

o Commensal budding yeasts that become pseudohyphae in opportunistic infections
o Usually antimicrobial treatment changes the flora and allows proliferation
o Also seen in stressed or immunocompromised animals, mostly young
o Prefers keratinized epithelium (mouth aka thrush, esophagus, crop aka sour crop)
o Produces enzymes that damage epithelium, anorexia causes keratin buildup
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Pig: thrush - Yellow-grey plaques on oral mucosa (tongue shown here)
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calf: Ventral sac of rumen Keratin may glue omental leaves together
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foal: Mostly around margo plicatus
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poultry: sour crop

Question 23

Histoplasma capsulatum (fungal)
- where does it live? forms?
- geography
- type of disease
- requires what dose or host factors
- GI?
- lesions
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- dog signs
- cats
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- microscope

Answer 23

o Soil-borne fungus that switches between hyphal (environment) and yeast (host) forms
o St. Lawrence River valley, mostly lung disease due to inhalation
o Needs high dose or immunocompromised host
o Can spread to gut and sometimes enteric only (ingestion?)
o May not have gross lesions or can have hemorrhagic enteritis
o Granulomatous inflammation thickens gut, can have ulcers and resemble neoplasia
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Dogs:
- Usually lungs only or disseminated
- Young dogs with hemorrhagic
diarrhea, tenesmus, weight loss
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Cats:
Usually disseminated
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Intracellular ‘fish-eye’ yeasts

Question 24

Pythiosis (algal)
- what animals, geographic range
- lesions, species

Answer 24

o Disease of immunocompetent animals in tropical/subtropical areas
o Best known for skin lesions in horses (‘swamp cancer’)
o Dogs usually develop GI lesions (due to drinking water)
o Segmental pyogranulomatous inflammation and ulcers

Question 25

Prototheca (P. zopfii and P. wickerhamii) (algal) - found where? - type of disease, species - signs, systems affected - lesions - prognosis

Answer 25

o Unicellular, opportunistic algae common in sewage, water, plant sap o Cutaneous disease in humans and cats, mastitis in cattle o Disseminated or GI in dogs, pathogenesis poorly understood (invasion of colon?) o Intractable hemorrhagic LI diarrhea, weight loss, dissemination to eyes and CNS o Hemorrhagic and ulcerative colitis with granulomatous inflammation o Poor prognosis