While the health effects of trypanosomes in Australian mammals in their native range are not fully understood, there is evidence of an impact in those species introduced to other geographical regions. Here we report the pathological and molecular features of concurrent fatal trypanosomiasis and toxoplasmosis in an adult female captive red-necked wallaby (syn. Bennett's wallaby; Macropus rufogriseus) from Bee County, Texas, USA. The animal exhibited no clinical signs prior to sudden death. On necropsy, the main findings were generalized organ congestion and bilateral renal petechiation. Microscopically, the main finding was lymphohistiocytic and necrotizing pancarditis with intrasarcoplasmic protozoal pseudocysts containing amastigotes and occasional intrahistiocytic amastigotes, morphologically compatible with Trypanosoma cruzi, as well as rare intrasarcoplasmic protozoal tissue cysts with zoites morphologically compatible with Toxoplasma gondii. Other lesions included acute centrilobular to panlobular necrotizing hepatitis with intrahepatocellular T. gondii cysts, necrotizing splenitis, pulmonary oedema with fibrin, histiocytosis and rare fibrin microthrombi, and acute renal tubular degeneration with proteinosis and pigmented casts suggestive of haemoglobinuria or myoglobinuria. Immunohistochemical labelling confirmed intralesional T. gondii cysts and molecular analyses identified T. cruzi genotype I and T. gondii. This is a unique case that, to the best of our knowledge, represents the first description of T. cruzi and T. gondii co-infection, as well as the first record of naturally occurring infection T. cruzi genotype I infection in macropodids. This case adds to the epidemiological knowledge on Chagas disease in the USA, particularly in Texas where there is a high prevalence of human and canine trypanosomiasis.

虽然锥虫体在其本地范围内对澳大利亚哺乳动物的健康影响尚不完全清楚，但有证据表明，这些锥虫体被引入其他地理区域。在这里，我们报告了成年女性圈养的红颈袋鼠（Syn。Bennett袋鼠；Macropus rufogriseus）中并发致命的锥虫病和弓形体病的病理和分子特征），来自美国德克萨斯州比尔县。在突然死亡之前，该动物没有任何临床体征。尸检的主要发现是全身性器官充血和双侧肾石化。在显微镜下，主要发现是淋巴组织细胞增生和坏死性全心膜炎，其肌内原生动物假囊肿含有变形虫和克鲁格氏锥虫，在形态学上与偶氮梭菌相溶，偶而组织学上也有偶发组织内囊虫，在形态上与弓形虫相容的少见肌浆内原生动物组织囊肿。其他病变包括急性小叶至小叶坏死性肝炎伴肝内弓形虫囊肿，坏死性脾炎，纤维蛋白引起的肺水肿，组织细胞增生和稀有的纤维蛋白微血栓，以及伴有蛋白血症和色素沉着的急性肾小管变性，提示血红蛋白尿或肌红蛋白尿。免疫组织化学标记证实病灶内的弓形虫囊肿，分子分析鉴定出克鲁斯氏菌基因型I和弓形虫。就我们所知，这是一个独特的情况，代表T的第一个描述。克氏锥虫和Ť。弓形虫共感染，以及天然存在的感染的第一个记录Ť。克鲁兹巨脚类动物的基因型I感染。这种情况增加了美国查加斯病的流行病学知识，特别是在得克萨斯人和人类锥虫病流行率很高的德克萨斯州。