Mast Cells in Canine Parvovirus-2–Associated Enteritis With Crypt Abscess

The role of mast cells (MCs) in allergic reactions and parasitic infections is well established. Their involvement in host immune response against bacterial and viral infections is reported. In this study, investigation is made to determine if MCs are associated with Canine parvovirus-2 (CPV-2)–induced enteritis with crypt abscess (ECA). Mast cell count (MCC) was made on toluidine blue–stained intestinal sections from a total of 34 dogs. These included 16 dogs exhibiting ECA positive for CPV-2 and negative for Canine distemper virus and Canine coronavirus by immunohistochemistry and fluorescent antibody test, 12 dogs with inflammatory bowel disease (IBD), and 6 non-ECA/non-IBD (control) dogs. The average total MCC per high-power field in ECA (40.8 ± 2.2) and IBD (24.7 ± 2.1) was significantly higher (P < .05) than in the control (3.4 ± 0.6). Although not significant (P > .05), MCC was also higher in ECA than in IBD. The present study for the first time has documented significantly increased MCs in CPV-2–associated ECA as was previously reported for IBD, showing that MCs may also play an important role in CPV-2–associated ECA. Further studies involving more CPV-infected dogs are recommended to substantiate the findings.