Canine parvovirus type 2 (CPV-2) is one of the most serious viral diseases affecting dogs. First identified in 1978, it spread rapidly worldwide and remains a major cause of mortality in unvaccinated dogs despite the availability of highly effective vaccines. Understanding the disease and its prevention is essential for dog welfare.
Pathogenesis
CPV-2 targets rapidly dividing cells — primarily intestinal crypt epithelium, bone marrow, and lymphoid tissue. Destruction of intestinal epithelium causes haemorrhagic diarrhoea and bacterial translocation; bone marrow suppression causes leucopaenia (low white blood cell count), severely impairing immune response. The combination of intestinal damage, dehydration, leucopaenia, and sepsis creates a rapidly fatal syndrome without aggressive supportive care.
Clinical Signs
- Acute onset vomiting and haemorrhagic diarrhoea — distinctive bloody, foul-smelling faeces
- Profound lethargy and depression
- Severe dehydration and electrolyte imbalances
- High fever or hypothermia (in shock)
- Abdominal pain
- Leucopaenia on blood count — often severe (<2.0 × 10⁹/L)
Diagnosis and Treatment
Faecal ELISA antigen tests provide rapid in-house diagnosis. Treatment is intensive supportive care:
- IV fluid therapy — the cornerstone of treatment; corrects dehydration and maintains perfusion
- Anti-emetics (maropitant) to control vomiting and allow oral/enteral nutrition
- Broad-spectrum antibiotics to prevent sepsis from bacterial translocation
- Plasma or colloid transfusion for severe hypoproteinaemia
- Nutritional support — early enteral feeding improves outcomes
- Intensive nursing care including isolation to prevent spread
Survival rates reach 80–95% with good intensive care; without treatment, mortality approaches 90%.
Welfare Impact
Parvovirus causes acute, severe suffering — haemorrhagic gastroenteritis, pain, and systemic illness are profound welfare harms. Treatment requires extended hospitalisation (5–10 days typically), during which puppies require constant nursing care. The welfare case for vaccination is overwhelming.
Prevention
Highly effective modified live virus (MLV) vaccines protect from 6–8 weeks of age. Maternal antibody interference requires puppy vaccination at 6–8, 10–12, and 14–16 weeks for complete protection. Annual boosters maintain immunity. Unvaccinated dogs should avoid contact with other dogs, contaminated environments, and soil until vaccination course is complete — parvovirus survives in soil for months to years.