6. Canine enteritis caused by parvoviruses.

Question 1

Canine enteritis?

Answer 1

Canine enteritis

• Parvoviridae, Parvovirinae, Protoparvovirus, Carnivore protoparvovirus 1, Canine parvovirus 2
• Dog, wolf, fox, canidae
• 3-8 weeks: sudden death, myocardial damage, high mortality (w/in 2-3 days)
• Above 8 weeks: enteritis, earlier mostly stinky greyish persistent diarrhoea, recently
• haemorrhagic forms, mortality approx. 10%
• Australia, USA 1977-78
• Spread everywhere
• Dogs are seropositive b/c of vaccination or infection
• CPV-1: original non-pathogenic viruses of dogs
• canine minute virus (Carnivore bocaparvovirus 1)
• CPV-2 ;(Carnivore protoparvovirus 1) since 1970s
• Cell culture mutant vaccine of cat panleukopenia virus
• Wild carnivore virus spread to dogs?
• Subtypes: since 1978 CPV-2a, later (since 1984) CPV-2b, CPV2c (since 2000) & New CPV2a b
• Subtypes replaced original CPV2 until 1981
• Cats can only be infected with the ‘a subtype’ 10% of all panleukopenia cases

Question 2

Pathogenesis?

Answer 2

Pathogenesis

• Viral intake: PO
• viral replication: lymphoid tissues around throat ĺ
• viremia (1st-2nd days )
• organs with rapid cell division
• (lymphoid cells: BM, spleen, thymus,
• LN, crypt cells of SI, myocardial cells of young animals!!)
• massive shedding of the virus from the 3rd-4th days (7-10 days: latent period of 1 week)
• Replication:
• In the lymphoid cells: lymphopenia & leukopenia
• In the crypt cells of SI: massive shedding of the virus, basal layer is damaged, damages intestinal vili, inflammation developed
• In the myocardium: myocarditis with necrosis
• Antibody 3rd- 4th days in the sera (latent period: 3-7 days)

Question 3

Clinical signs and pathology?

Answer 3

Clinical signs

• Non-specific signs (fever, laziness, weakness)
• Acute gastroenteritis (vomiting, diarrhoea, painful abdomen, exsiccosis due to dehydration)
• Outcome depends on age/immunity
• Susceptible, young (less than 8weeks, replicate in myocardial) = dead within 2-3 days (50%)
• Older/adults: 8-12 days sub chronic symptoms subclinical infection
• In case of myocarditis: dead w/out symptoms or after dyspnoea & diarrhoea
• Pathology:
• edema in GI, hemorrhages in SI mucosa: sometimes very visible
• (patho!) If young puppy: paler area which is myocardial disease

Question 4

Histopathology?

Answer 4

Histopathology

• Intestinal mucosa: inflammation, haemorrhages, desquamation, basophilic nuclear
• inclusion bodies in intestinal cells
• Mesenterial LNs, spleen: decr lymphoid cells
• In case of myocarditis: basophilic nuclear inclusion bodies,
• infiltration with lymphoid & plasma cells - in nucleus of cell see the replication of the virus

Question 5

Diagnosis?

Answer 5

Diagnosis

• Clinical signs, anamnesis (vaccinated/non-vaccinated)
• Virus detection from faeces:
• HA swine RBCs
• PCR
• Sandwich ELISA
• EM
• Rapid tests: positive for 10-15 days after live
• vaccines/maternal immunity!! Which is false positive
• Antibody detection: only if extreme high or increasing, HAG, VN, ELISA(IgM, IgG): Rapid tests Sera (Maternal immunity vaccine)

Question 6

Differentiate?

Answer 6

Differentiate:

• Coronavirus:
• CCoV-I: young dogs, vomiting, watery diarrhoea,
• CCoV-II: 1.5-2 month old, haemorrhagic enteritis, vomiting, ataxia
• Herpesvirus: below 2-3 weeks of age, deadly outcome
• haemorrhagic, mostly respiratory, 80% mortality until 1 week of age
• Rotavirus:
• milder, haemorrhagic diarrhoea is unusual
• Parvovirus in the crypt cells!

Question 7

Treatment and Prevention?

Answer 7

Treatment:

• Treat the clinical condition
• antibiotics for secondary infections
• quarantine
• hyperimmune sera (!)

Prevention:

• general rules of epidemiology
• Vaccines: inactivated (live attenuated)
• Maternal antibodies protect up to 3-4 months
• Hyperimmune serum (best before the clinical signs) Immune response ʹ protection