Canine Parvovirus

1
Canine Parvovirus

• Michigan State University
• Van Dang
• Karissa Slusher

2
History

• Emerged in 1977-1978
• Feline Panleukopenia
• Extremely hardy, survives outside its host for up
  to 6 months
• Species specific

3
What is it?

• Canine parvovirus
• Smallest virus
• Naked, icosahedral capsid
• ssDNA (5 kb)
• Replicates only when host is replicating!
• 2 Syndromes
• Acute myocarditis
• Hemorrhagic enteritis

4
Incidence

• Any age can become infected
• Mild and Asymptomatic
• Severe clinical disease
• Puppies 2 to 6 months of age
• Rottweilers and Doberman Pinchers

5
Life cycle of Parvovirus
6
Clinical syndrome

• Host vitality
• Immune experience, vaccination status
• Environment
• Humidity, temperature, etc
• Virulence of the virus
• Including viral load

7
Protection

• Colostrum
• Maternal antibodies protective until 2 month of
  age
• Regular Vaccination
• Keep indoors
• Until the vaccination series are complete

8
Pathogenesis
Tonsils Replicates in Lymphocytes in the next
3-4 days
Cell lysis ? Viremia
Bone Marrow Stem cells
GIT
9
Hemorrhagic enteritis

• Villi become blunted and unable to absorb
  nutrients.
• Barrier to GIT flora is broken down.

10
Mechanisms of Death

• Diarrhea and vomiting
• ?extreme dehydration ? SHOCK
• Loss of intestinal barrier
• ? bacterial invasion ? SEPTIC SHOCK

11
Symptoms

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

12
Differential Diagnoses

• Canine Distemper
• Infectious Canine Hepatitis
• Canine Coronavirus
• Salmonellosis
• Campylobacteriosis
• Hemorrhagic Gastroenteritis (HGE)
• Toxicosis

13
Diagnosis

• History and PE
• Symptoms
• ELISA (CITE)
• False positives with recent vaccination Hx
• Antibody titer
• CBC
• Biopsy
• Necropsy
• Lower and middle small intestines
• Bone marrow

14
Biopsy of the Small Intestine
collapsed crypts
depleted Peyers patches
15
Inclusion bodies in Crypt cells
Kelly, 1978
16
Additional tests

• Serum chemistry
• UA
• Fecal flotation

17
Symptomatic Treatment

• Fluids
• Antimetics
• Antibiotics
• Antihelmintics
• Colloids, plasma, RBC

18
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

19
Home care

• Antibiotics (PO)
• Diet management
• Bland, highly digestible food
• Frequent, small feedings
• Restricted activity
• Avoid introducing new puppies
• Disinfect with bleach

20
CPV Vaccine History

• Original vaccines incorporated feline
  panleukopenia virus or mink enteritis viruses
• Similar to the original CPV
• Killed and MLV were developed, but variable
  efficacy
• Low titer
• Interference of Maternal antibodies

21
Vaccine History

• Mid 1990s
• New generation, high titer, low-passage CPV
  vaccines
• Pfizer (Vanguard Puppy)
• Fort Dodge (Duramune / Puppy Shot)
• Intervet (Progard)
• Merial (Recombitek C4 and C6)
• Schering-Plough (Galaxy)

22
CPV High Titer Vaccine

• Contains more virus than standard vaccine
• Better at inducing immunity in puppies at a
  younger age

23
Passaging

• Passaging is the process of growing and modifying
  a virulent virus to one that is safe for the use
  in a vaccine
• Each generation passage is less like the original

24
Vaccine Failure Interference by Maternal
Antibodies

window of susceptibility

minimum level needed for protection

passive antibody
HAI - 80

HAI - 10 to 20

Successful Vaccination

2
4
6
8
10
12
weeks after birth
25
Maternal Antibodies

• Critical period and vaccine response varies with
  the individual
• Dams antibody level
• First born, aggressive pups
• More colostrum ? Higher MA

26
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
• Amount of attenuated virus in each dose
• No vaccine produces 100 immunity

27
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

28
CPV Vaccination Recommendations

• Use modified live vaccines for puppies
• Start vaccinations at 6-8 weeks of age
• Vaccinate every 3-4 weeks until 15-16 weeks of
  age
• Giving a vaccine more frequently than every 2
  weeks will cause interference
• This includes vaccines for different infections

29
CPV Vaccination Recommendations

• Annual Booster
• Debatable
• Killed vaccines
• Least effective at penetrating maternal antibody
• Also associated with more vaccine reactions

30
Other Parvoviruses

• Feline Panleukopenia Virus
• Porcine Parovirus
• Aleutian Mink Diseases

31
(No Transcript)
32
References

• http//www.marvistavet.com/html/the_parvo_virus_in
  _the_environ.html
• http//www.cdc.gov/ncidod/eid/vol8no4/01-0228.htm
• http//www.agen.com.au/products/parvo.htm
• http//www.ivis.org/advances/Infect_Dis_Carmichael
  /truyen/chapter_frm.asp
• http//home.europa.com/dshecklr/Vaccinations1.htm
  l
• http//www.mesavet.com/library/vaccination_failure
  s.htmineffective
• http//www.awebresource.com/gvh/newsletters/vaccin
  es.htm
• http//www.spinone.com/newsletters/V04N1/p09b.htm
•  
•