December 2024

​Oinkmas: A piggy Christmas story

A 4-month-old pig was brought for necropsy examination at the Oklahoma Animal Disease Diagnostic Laboratory. The pig had recently died along with 3 other pigs (same age).  All had a history of anorexia, low fever and diarrhea.  The other 3 pigs had traces of blood on feces.
During gross examination, gastritis, enterocolitis and numerous small parasites in the intestine were observed (not recovered). No parasite eggs, oocysts or cysts were recovered during fecal centrifugation from colon content. Histological examination revealed colitis, lymphoplasmacytic, histiocytic, neutrophilic and eosinophilic, with crypt abscess, chronic, moderate and intraepithelial and intraluminal nematodes (Figure 1).

Thanks to Drs. Clare Brown and Daniel Barrantes-Murillo for contributing to this case.

Figure 1: ​A. Intraepithelial and intraluminal nematodes (arrowheads). Hematoxylin and eosin (HE). Bar = 400 mm. B. Transversal sections of intraluminal parasites. BB = bacillary band, C = cuticle, HY = hypodermis, SN = stichosome nucleus. HE. Bar = 60 mm. C. Transversal sections of intraluminal parasite. BB = bacillary band, CA = cuticular annulations, HY = hypodermis, S = stichosome. HE. Bar = 60 mm. D. Transversal sections of intraepithelial parasites. Pseudocoelom (asterisks) and polycytous intestine containing uninucleate epithelial intestinal cells (UI). HE. Bar = 60 mm. E. Transversal sections of intraluminal parasite. Hologenic ovary (O), polymyarian coelomyarian muscle (asterisk) and polycytous intestine containing uninucleate epithelial intestinal cells (UI). HE. Bar = 60 mm. F. The lamina propria is moderately expanded by the infiltration of moderate numbers of lymphocytes, plasma cells, histiocytes and fewer neutrophils and eosinophils, with crypt abscess (asterisk). HE. Bar = 60 mm.

What's your diagnosis?

​Trichuris suis, commonly known as whipworms are trichinellid parasites that live embedded within the epithelial cells of the large intestine, especially the cecum. Severe T. suis infections in young swine cause catarrhal enteritis with diarrhea, anorexia, and retardation of growth.  Control of this parasite depends on separating swine from source of infective eggs, while treatment has been successful using Fenbendazole or Dichlorvos.