Baneth Gad, Samish Michael, Shkap Varda
School of Veterinary Medicine, Hebrew University of Jerusalem, PO. Box 12, Rehovot 76100, Israel.
J Parasitol. 2007 Apr;93(2):283-99. doi: 10.1645/GE-494R.1.
The life cycle of the apicomplexan protozoon Hepatozoon canis in its natural hosts Rhipicephalus sanguineus (tick) and Canis familiaris (domestic dog) was studied in an experimental infection. Tick nymphs were fed on a naturally infected dog, or they were infected by percutaneous injection of blood. Dogs were inoculated by ingestion of adult ticks containing mature oocysts. Gamonts were in syzygy 24 hr after percutaneous injection of ticks. Early oocysts were detected 96 hr after nymph repletion, and mature oocysts in adult ticks were infective to dogs 40 days postmolt. Merogony was detected in dog bone marrow from 13 days postinoculation (PI) and included meronts containing 20-30 micromerozoites, and a second type with 2-4 macromerozoites. Monozoic cysts were observed in the spleen in conjunction with merogony. Gamontogony with infection of leukocytes by micromerozoites occurred from 26 days PI, and gamont parasitemia, which completed the life cycle, was detected 28 days PI. The length of the life cycle from nymphal attachment to parasitemia in dogs was 81 days. Increased body temperatures were evident from 16 to 27 days PI and paralleled the time of intensive bone marrow merogony. Skeletal pain and recumbency were manifested in 2 dogs. This study further elucidates the life cycle of H. canis and provides a sequential morphologic description of H. canis merogony, gamontogony, and sporogony.
在一次实验性感染中，研究了顶复门原生动物犬肝簇虫在其天然宿主血红扇头蜱（蜱）和家犬（家犬）中的生命周期。蜱若虫以自然感染的狗为食，或者通过经皮注射血液进行感染。狗通过摄入含有成熟卵囊的成年蜱进行接种。经皮注射蜱后24小时，配子体出现配对。在若虫饱血后96小时检测到早期卵囊，成年蜱中的成熟卵囊在蜕皮后40天对狗具有感染性。接种后13天在狗骨髓中检测到裂体增殖，包括含有20 - 30个小裂殖子的裂殖体，以及另一种含有2 - 4个大裂殖子的类型。在脾脏中观察到与裂体增殖相关的单胚层囊肿。小裂殖子感染白细胞的配子生殖从接种后26天开始，接种后28天检测到完成生命周期的配子体血症。从若虫附着到狗出现虫血症的生命周期长度为81天。接种后16至27天体温明显升高，与骨髓强烈裂体增殖的时间一致。2只狗出现骨骼疼痛和卧地不起的症状。本研究进一步阐明了犬肝簇虫的生命周期，并提供了犬肝簇虫裂体增殖、配子生殖和孢子生殖的连续形态学描述。
