Canine Parvovirus

Prepared By:

Pradhuman YadavB.V.Sc & A.HB.V.Sc & A.H

History

• Emerged in 1977-1978• Feline Panleukopenia• Extremely hardy• Survives outside its host for up to

6 months• Species specific

What is it?

• Canine parvovirus• Smallest virus• Naked, icosahedral capsid• ssDNA

Replicates only when host is replicating! • 2 Syndromes:

• Acute myocarditis• Hemorrhagic enteritis

Incidence

• Any age can become infected• Mild and Asymptomatic• Severe clinical disease

• Puppies 2 to 6 months of age• Rottweilers and Doberman Pinchers

Life cycle of Parvovirus

Clinical syndrome • Host vitality

• Immune experience, vaccination status

• Environment • Humidity, temperature, etc

• Virulence of the virus• Including viral load

Protection

• Colostrum• Maternal antibodies protective until 2 month

of age

• Regular Vaccination• Keep indoors

• Until the vaccination series are complete

PathogenesisTonsilsTonsils

Replicates in Lymphocytes in the next 3-4 days

Cell lysis Cell lysis Viremia Viremia

Bone MarrowBone MarrowStem cells GITGIT

Mechanisms of Death

1. Diarrhea and vomiting extreme dehydration SHOCK

2. Loss of intestinal barrier bacterial invasion SEPTIC SHOCK

Symptoms

• Fever, lethargy, anorexia.• Severely dehydrated.• Vomiting.• Diarrhea: watery, bloody, with a tell-tale

odor.

Symptoms Shown By Dog

Hemorrhagic enteritis

• Villi become blunted and unable to absorb nutrients.

• Barrier to GIT flora is broken down.

Biopsy of the Small IntestineCollapsed cryptsCollapsed crypts

Depleted Peyer’s patchesDepleted Peyer’s patches

Inclusion bodies in Crypt cells

Kelly, 1978Kelly, 1978

Diagnosis• History and physical examination.• Symptoms• ELISA

• False positives with recent vaccination Hx• Antibody titer• CBC (Complete Blood Count).• Biopsy• Necropsy

• Lower and middle small intestines• Bone marrow

Additional tests

• Serum chemistry.• UA (Urine Analysis).• Fecal flotation• Rapid immunochromatographic tests.• Hemmaglutination inhibition test.• Fluorescence antibody test.

Symptomatic Treatment

• Fluids - Colloids, Plasma, RBC

• Antimetics - Metoclopramide• Antibiotics - Cefoxitin, Enrofloxacin.• Antihelmintics - Pyrental

• Analgesic - Buprenorphine

Prognosis• Most recover with intensive therapy

• Dobermans and Rottweilers • Sensitive to the virus

• Poor prognosis• Intussusception

• Hypoproteinemia

• No improvement after 4th day of intesive care

Home care• Antibiotics (PO)• Diet management

• Bland, highly digestible food• Frequent, small feedings

• Restricted activity• Avoid introducing new puppies

• Disinfect with bleach

Maternal Antibodies

• Critical period and vaccine response varies with the individual • Dams antibody level

• First born, aggressive pups

• More colostrum Higher MA

Vaccine Failure: Interference by Maternal

Antibodies

2 4 6 8 10 12

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Pass

ive

antib

ody

Weeks after birth

Minimum level needed for protection

Window ofsusceptibility

HAI - 80

HAI - 10 to 20Successful Vaccination

Vaccine Failure

• Ineffective Vaccine • Inappropriate storage

• Inappropriate administration

• Low titer vaccine

• Immunogenicity and Serological response• Virulence of parent viral strain

• Method and level of virus attenuation

• No vaccine produces 100% immunity

Vaccine Failure

• Health Status• Fever• Immunocompromised animals

• Client Compliance• Recommended vaccination schedule

• Breed• A disproportionate number of Rottweilers

that have been properly vaccinated will develop parvo