Mean platelet volume and platelet volume distribution width in canine parvoviral enteritis

Background: Bacterial translocation from the damaged intestinal tract, reported in canine parvoviral (CPV) enteritis, is thought to be responsible for the systemic inflammatory response resulting from coliform septicaemia, which could ultimately progress to septic shock and death. Alterations in platelet indices, specifically mean platelet volume (MPV), is a consistent finding in critically ill people and dogs with and without sepsis. Increased MPV has been reported to be an indirect indicator of platelet activation and of bone marrow response in people and dogs with sepsis.

Hypothesis: We hypothesised that the platelet indices, specifically MPV, Platelet volume distribution width (PVDW), and mean platelet mass (MPM) would be increased, whereas mean platelet component concentration (MPC) would be decreased in dogs infected with CPV compared to that of healthy controls and that these changes would correlate with the degree of inflammation.

Animals: Forty-eight client-owned dogs infected with CPV enteritis and 18 healthy age-matched control dogs.

Methods: Prospective, observational study conducted at the Onderstepoort Veterinary Academic Hospital, University of Pretoria, South Africa over an 11-month period. Blood and fresh faecal samples were collected once at presentation from dogs aged 6 weeks to 9 months that were diagnosed with CPV and admitted for treatment, and from apparently healthy dogs presenting for vaccination or routine hospital procedures. CPV infection was confirmed by identification of the virus with electron microscopy on the faecal samples. EDTA whole blood samples were analysed on an automated cell counter, ADVIA 2120, within 30-60 minutes from collection.

Results: There was no significant difference for platelet count between the groups. The MPV for CPV infected dogs (median: 14.0; IQR: 12.2-15.1) was significantly higher compared to controls (11.3; IQR: 10.3-13.1, P=0.002). The PVDW for CPV infected dogs (66.9; IQR: 64.2-68.8) was significantly higher compared to controls (63.3; IQR: 60.2-65.1, P<0.001).

Conclusions and clinical importance: These findings suggest that significant platelet activation is present in dogs with CPV enteritis which may play a role in the disease outcome, similar to people with sepsis. Further studies are required to investigate the prognosticating ability of MPV in dogs with CPV enteritis.