Dubey J P, Chapman Jennifer L, Rosenthal Benjamin M, Mense M, Schueler Ronald L
United States Department of Agriculture, Agricultural Research Service, Animal and Natural Resources Institute, Animal Parasitic Diseases Laboratory, Beltsville Agricultural Research Center, Beltsville, MD 20705-2350, USA.
Vet Parasitol. 2006 Apr 15;137(1-2):36-49. doi: 10.1016/j.vetpar.2005.12.017. Epub 2006 Feb 3.
Sarcocystis neurona, Sarcocystis canis, Toxoplasma gondii, and Neospora caninum are related apicomplexans that can cause systemic illness in many species of animals, including dogs. We investigated one breeder's 25 Basset Hounds for these infections. In addition, tissues from dogs and other non-canine hosts previously reported as S. canis infections were studied retrospectively. Schizonts resembling those of S. neurona, and recognized by polyclonal rabbit anti-S. neurona antibodies, were found in six of eight retrospective cases, as well as in two additional dogs (one Basset Hound, one Springer Spaniel) not previously reported. S. neurona schizonts were found in several tissues including the central nervous system, lungs, and kidneys. Fatal toxoplasmosis was diagnosed in an adult dog, and neosporosis was diagnosed in an adult and a pup related to the one diagnosed with S. neurona. No serological reactivity to S. neurona antibodies occurred when S. canis-like liver schizonts were retrospectively assayed from two dogs, a dolphin, a sea lion, a horse, a chinchilla, a black or either of two polar bears. Sequencing conserved (18S) and variable (ITS-1) portions of nuclear ribosomal DNA isolated from the schizont-laden liver of a polar bear distinguished it from all previously characterized species of Sarcocystis. We take this genetic signature as provisionally representative of S. canis, an assumption that should be tested with future sequencing of similar liver infections in other mammalian hosts. These findings further extend the uncharacteristically broad intermediate host range for S. neurona, which also causes a neurologic disease in cats, mink, raccoons, skunks, Pacific harbor seals, ponies, zebras, lynxes, and sea otters. Further work is necessary to delineate the causative agent(s) of other cases of canine sarcocystosis, and in particular to specify the attributes of S. canis, which corresponds morphologically to infections reported from wide range of terrestrial and marine mammals.
犬肉孢子虫、犬新孢子虫、刚地弓形虫和犬新孢子虫是相关的顶复门原虫，可在包括犬在内的许多动物物种中引起全身性疾病。我们调查了一位饲养员的25只巴吉度猎犬是否感染这些病原体。此外，对先前报告为犬肉孢子虫感染的犬和其他非犬宿主的组织进行了回顾性研究。在八例回顾性病例中的六例以及另外两只此前未报告的犬（一只巴吉度猎犬、一只激飞猎犬）中发现了类似于犬肉孢子虫裂殖体且能被兔抗犬肉孢子虫多克隆抗体识别的裂殖体。犬肉孢子虫裂殖体存在于包括中枢神经系统、肺和肾脏在内的多种组织中。在一只成年犬中诊断出致命的弓形虫病，在一只成年犬和一只幼犬中诊断出新孢子虫病，这只幼犬与诊断出感染犬肉孢子虫的犬有关。当对两只犬、一只海豚、一只海狮、一匹马、一只毛丝鼠、一只黑熊或两只北极熊中的任何一只进行回顾性检测时，类似犬肉孢子虫的肝脏裂殖体对犬肉孢子虫抗体没有血清学反应。对从一只北极熊充满裂殖体的肝脏中分离出的核糖体DNA保守部分（18S）和可变部分（ITS-1）进行测序，将其与所有先前鉴定的肉孢子虫物种区分开来。我们将这种基因特征暂定为犬肉孢子虫的代表，这一假设应通过对其他哺乳动物宿主类似肝脏感染的未来测序进行验证。这些发现进一步扩展了犬肉孢子虫异常广泛的中间宿主范围，犬肉孢子虫还会在猫、水貂、浣熊、臭鼬、太平洋斑海豹、小马、斑马、猞猁和海獭中引起神经疾病。有必要开展进一步工作来确定其他犬肉孢子虫病病例的病原体，特别是明确犬肉孢子虫的特征，其在形态上与广泛的陆地和海洋哺乳动物中报告的感染相对应。
