Abstract

A syndrome of necrotic enterocolitis and typhlitis has been documented in 50 free-ranging ring-tailed lemurs (Lemur catta) on St. Catherine’s Island (SCI) over the last 15 years, and in 14 semi free-ranging lemurs (Lemur catta, Varecia rubra, and Eulemur mongoz) at the Lemur Conservation Foundation over a 7-year period. A workshop on this syndrome was hosted by SCI Foundation in November 2012 involving all of the authors. The following conclusions were reached: Younger lemurs 4–15 mo of age are more commonly affected, although not exclusively. The case fatality rate is approximately 80–90%. The following case definition for this syndrome was developed: 1) Lemurs present with acute-onset abdominal pain, lethargy, anorexia, +/- diarrhea or no defecation with hypoalbuminemia; 2) Necropsy findings include mucosal to transmural necrosis of the cecum, small intestine and/or large intestine.

The histopathology seen with this syndrome resembles human appendicitis, and suggests that ischemia may be the underlying pathophysiologic mechanism. Although numerous bacteria and occasional fungal organisms are observed on histopathology and recovered by culture, they appear to be the result of opportunistic invasion rather than a primary cause. No specific pathogens have been consistently recovered, although findings have included an adenovirus-like organism, a parvo-like virus, a β-coronavirus, Lawsonia spp., or Salmonella spp. Workshop participants concluded that 1) localized ischemia and/or hypomotility may be predisposing lemurs to develop this syndrome; 2) an infectious cause is unlikely; and 3) ingestion of a plant or toxin is a possible primary cause, but further exploration is needed.