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Cytauxzoon felis produces a disease in domestic cats in the Midwest (U.S.A.), which often leads to a fatal outcome. Although the clinical disease process is well described, there are still many unanswered questions about this organism. For example, it is unknown whether species of ticks other than Dermacentor variabilis can serve as vectors for transmission. With recent reports of surviving cats from limited geographic areas, another relevant question is the potential for genetically less virulent organism strains. This study evaluated 352 individual or pooled tick samples (1,362 total ticks) for the presence of C. felis small subunit ribosomal RNA and internal transcribed spacer 1 (ITS-1) region genes using a polymerase chain reaction (PCR). These ticks were collected from dogs and cats in several Missouri counties, including 10 from cats diagnosed with cytauxzoonosis. Only 3 positive C. felis samples were identified in Amblyomma americanum nymphs, and there was very limited genetic variation noted in both genes. The small number of positive samples did not allow the study to determine which PCR analysis was more sensitive. This is the first known report of ITS-1 gene identification and sequencing for C. felis. It is also the first published investigation of genetic variation in C. felis.

A 4-month-old sexually intact male Jack Russell Terrier was evaluated because of stranguria and tenesmus. A tubular abdominal mass was palpable abdominally and rectally. Radiographic examination of the abdomen revealed a soft tissue mass located laterally and to the left of the descending colon, which was associated with extraluminal colonic obstruction and urethral compression. During abdominal exploratory surgery, a large cystic mass that was adhered to the antimesenteric border of the descending colon was removed. Porcine small intestinal submucosa was used to reinforce repair of the excision site. Histologic examination of samples of excised tissue identified normal colonic epithelium supported by submucosa and muscular tunics, which was consistent with duplication of the colon. The embryologic etiology of alimentary duplication is poorly understood, and colonic duplication is an extremely rare congenital anomaly.