Canine Parvovirus

Introduction

Until 1978 Parvovirus enteriris was totally unknown in dogs - it was first seen in dogs in Australia where it appeared very similar but perhaps slightly worse than the disease seen in the cat. Research revealed a new and distinct disease, but the virus is very closely related to the feline virus; viral DNA is 98% homologous to the feline virus. Clinically, the virus causes enteritis mainly affecting the small intestine in young dogs over 6 weeks old and myocarditis in puppies. Vaccines are very effective, but the virus is hardy and survives for a protracted time in the environment.

Antigenicity

• 2 Canine viruses have been identified:
  • Canine Parvovirus 1 (CPV1): avirulent and ubiquitous in the canine population
  • Canine Parvovirus 2 (CPV2): a new virus that emerged in the late 1970's

Antigenic variants do naturally occur.

Signalment

The virus predominantly affects dogs, but CPV 2a/2b can cause clinical disease in cats.

Pathogenesis

Oropharyngeal infection is followed by viremia. Subsequently there are 2 distinct syndromes:

1. Myocarditis in puppies aged 3-8 weeks - the virus targets rapidly dividing myocardium leading to sudden death, or fading puppy syndrome. This is now rare due to widespread passive immunity.
2. Enteritis in puppies >6 weeks of age. The virus targets intestinal crypts, causing the villi to shorten and the destruction of cypt cells, leading to gray, persistent, foul-smelling diarrhoea or hemorrhagic enteritis. CPV has a high morbidity but low mortality (10%) rate.

Epidemiology

Transmission is by the Orofaecal route. The host range is controlled by only a few amino acids

Diagnosis

• HA or ELISA to confirm viral infection
• Viral antigen can be detected in the faeces by the red cell agglutination test
• Immunofluorescence
• Serology

Prevention and Control

• Vaccination, usually given in combination with distemper and hepatitis. With first vaccination at 8-10 weeks and the second vaccination two weeks after the first, 10-12 weeks. Earlier vaccinations can be given where breeders are known to have CPV on the premises.
• Thorough disinfection after disease or removing dogs from that area for at least 9 months.