The Philadelphia Zoo has maintained a colony of Iberian ribbed newts since their acquisition in 1998. In January 2012, a newt presented for abnormal buoyancy and was found impacted with a palpable hard intracoelomic mass. An enterotomy was performed to remove a colonic mass consisting of firm, dark, unidentifiable material. One month later, additional surgery was performed to repair incisional dehiscence and a markedly dilated distal colon was noted at that time. One year later, the same newt again had surgery to relieve a colonic impaction with similar material. This animal was euthanized 1 mo later after postoperative complications due to recurrent incisional dehiscences. In August 2013, another newt underwent surgery to relieve a colonic impaction. This animal experienced postoperative incisional complications which were resolved using stented sutures. This newt healed completely and remains alive 11 mo postoperatively.
Review of all records from 1998–2014 identified nine additional newts with marked colonic dilation and impactions. Necropsy findings for all cases have been consistent, describing a firm, dark mass markedly distending the distal colon as the likely cause of death. Modified Gimenez (PVK) stains were performed to test for Chlamydophila spp. in six cases in which granulomatous inflammation was seen on histology and all were negative. The etiology of these impactions has not been determined although sources from within the enclosure appear unlikely. A dietary source remains a possibility. Following a switch in diet from earthworms to redworms (Alloloborpha caliginosa) no additional cases have been seen to date.
The authors are grateful to the technical staff at the Philadelphia Zoo for their assistance during the procedures and to the keepers who care for these animals on a daily basis. The authors acknowledge Alisa L. Newton, VMD, Dipl. ACVP for her diagnostic work in a portion of these cases.