<i>Aliarcobacter butzleri</i> colitis in rhesus macaques ( <i>Macaca mulatta</i> )

<i>Aliarcobacter butzleri</i> is a <i>Campylobacter</i>-like bacteria associated with watery diarrhea in humans and is infrequently reported in nonhuman primate (NHP) populations. While clinical and microscopic features in humans are indistinguishable from <i>Campylobacter</i> spp. infection, descriptions of <i>A. butzleri</i>-associated colitis in NHP are lacking. Here, we describe the clinical and pathological features of diarrhea and colitis associated with <i>A. butzleri</i> in rhesus macaques using a retrospective approach. Over a 3-year period, <i>A. butzleri</i> was isolated from 10 macaques with diarrhea. Five of the 10 were submitted for necropsy and had features of chronic enterocolitis, consistent with existing literature. However, 40% (2/5) of the cases were characterized by ulcerative colitis, which has not previously been described as a feature of <i>A. butzleri</i> colitis. <i>A. butzleri</i> should be considered a differential diagnosis in cases of diarrhea and enterocolitis in captive rhesus macaques.