Kocan K M, Stiller D
College of Veterinary Medicine, Oklahoma State University, Stillwater 74078.
J Med Entomol. 1992 Jan;29(1):98-107. doi: 10.1093/jmedent/29.1.98.
The development of Anaplasma ovis was studied in Dermacentor andersoni males transferred from infected to susceptible sheep. Laboratory-reared male D. andersoni were allowed to feed for 6 d on a sheep with ascending A. ovis parasitemia. The ticks were removed and held at room temperature in a humidity chamber for 6 d, after which they were allowed to feed on five susceptible sheep for 1, 3, 5, 7, or 9 d. Gut and salivary glands were collected from ticks during the 21-d experiment and examined with light and electron microscopy. Anaplasmosis developed in all susceptible sheep. Colonies of A. ovis were first observed in midgut epithelial cells on the 3rd d ticks fed on the infected sheep, and infection persisted in gut cells throughout the experiment. The first colonies contained one large organism that subsequently gave rise to many reticulated ones, which became electron dense over time. After ticks were transferred to susceptible sheep and began the second feeding, individual A. ovis organisms were found from days 3-9 in muscle cells on the hemocoel side of the gut basement membrane. However, colonies did not develop in these cells, and the host cells did not hypertrophy as did cells similarly infected with A. marginale. A final site of development of A. ovis was in salivary glands. Individual organisms were first seen in acinar cells on the first day that ticks fed on the second calves, and salivary gland infections persisted throughout the 9-d feeding period. Colonies of A. ovis developed in salivary gland acinar cells and organisms within these colonies were initially electron lucent but became electron dense. Multiple colonies often were observed within salivary gland cells and often contained organisms in various stages of development.
研究了从感染绵羊转移至易感绵羊身上的安德森革蜱雄蜱中绵羊无形体的发育情况。将实验室饲养的安德森革蜱雄蜱置于一只患有逐渐加重的绵羊无形体血症的绵羊身上吸血6天。蜱虫被移除后，在室温的湿度箱中放置6天，之后让它们在五只易感绵羊身上分别吸血1、3、5、7或9天。在为期21天的实验过程中，从蜱虫身上采集肠道和唾液腺，并用光学显微镜和电子显微镜进行检查。所有易感绵羊都感染了无形体病。在蜱虫吸食感染绵羊血液后的第3天，首次在中肠上皮细胞中观察到绵羊无形体菌落，并且在整个实验过程中，肠道细胞中一直存在感染。最初的菌落包含一个大型生物体，该生物体随后产生了许多网状生物体，随着时间的推移，这些生物体变得电子致密。蜱虫转移至易感绵羊并开始第二次吸血后，在第3至9天，在肠道基底膜血腔侧的肌肉细胞中发现了单个的绵羊无形体生物体。然而，这些细胞中并未形成菌落，并且宿主细胞也没有像感染边缘无形体的细胞那样肥大。绵羊无形体的最终发育部位是唾液腺。在蜱虫吸食第二只小牛血液的第一天，首次在腺泡细胞中看到单个生物体，并且在整个9天的吸血期内，唾液腺感染一直持续。绵羊无形体菌落在唾液腺腺泡细胞中形成，这些菌落中的生物体最初电子透明，但后来变得电子致密。在唾液腺细胞内经常观察到多个菌落，并且通常包含处于不同发育阶段的生物体。
