A commercial producer hatching and rearing chukar partridges (Alectoris chukar) in Ontario, Canada had flocks experiencing coccidiosis. Microscopic analysis of Eimeria species isolated from a field sample indicated the presence of 2 distinct oocyst morphotypes; the most abundant species was determined to be Eimeria chapmani, based on oocyst morphology and sequence-based genotyping, and the less abundant, second Eimeria sp. was an undescribed parasite. Oocysts of the unknown Eimeria sp. were large and oval-shaped; dimensions averaged 27.9 μm by 17.0 μm (shape index = 1.65 μm). Oocysts contained at least 1 polar granule and 4 almond-shaped sporocysts with average dimensions measuring 12.5 μm by 6.9 μm (shape index = 1.83). Each sporocyst featured a Stieda body, sub-Stieda body, and sporocyst residuum; a sporocyst contained 2 sporozoites that each possessed a small anterior refractile body and a larger posterior refractile body. Virtually all oocysts sporulated after 24 hr when suspended in potassium dichromate at room temperature (22 C) on a rotary platform. Experimental infections with various doses of oocysts demonstrated elevated parasite shedding from birds gavaged with higher challenge doses; fecundity generally decreased in heavier infections. The approximate prepatent period of the parasite was 4–5 days (unsporulated oocysts observed histologically at 90 hr postinfection and in feces by day 5) and patency lasted until day 12 postinfection. To characterize the endogenous development of the Eimeria sp., tissues were collected at 8 regions along the intestinal tract (including the ceca and rectum) every 6 hr throughout the estimated prepatent period. Parasites were observed to infect the descending and ascending duodenum, midjejunum, proximal and distal ileum, and the ceca. The endogenous stages identified included intracellular sporozoites, 3 generations of merogony, and gametogonic stages. Sequences of the mitochondrial genome (GenBank MW934555) and nuclear 18S ribosomal DNA (GenBank MW934259) were obtained using polymerase chain reaction amplification for Sanger sequencing, and these were unique from all published sequences on GenBank. Molecular data, in conjunction with the unique biology of the Eimeria sp. isolated from the chukar partridge flock, support that this coccidium is new to science.

加拿大安大略省一家孵化和饲养石鸡（Alectoris chukar）的商业生产商的鸡群患有球虫病。对从现场样品中分离出的艾美耳球虫物种进行的显微镜分析表明存在 2 种不同的卵囊形态类型；根据卵囊形态和基于序列的基因分型，最丰富的物种被确定为查帕艾美耳球虫（Eimeria chapmani） ，而第二丰富的物种是艾美耳球虫（Eimeria sp.）。是一种未被描述的寄生虫。未知艾美耳球虫的卵囊。大且呈椭圆形；尺寸平均为 27.9 μm x 17.0 μm（形状指数 = 1.65 μm）。卵囊含有至少 1 个极性颗粒和 4 个杏仁形孢子囊，平均尺寸为 12.5 μm x 6.9 μm（形状指数 = 1.83）。每个孢子被均具有 Stieda 体、亚 Stieda 体和孢子被残留物；一个孢子囊含有2个子孢子，每个子孢子都有一个小的前折射体和一个较大的后折射体。当在室温（22°C）下悬浮在旋转平台上的重铬酸钾中时，几乎所有卵囊在 24 小时后形成孢子。用不同剂量的卵囊进行的实验感染表明，用较高的攻击剂量灌胃的鸟类的寄生虫脱落率增加；感染较重时，繁殖力通常会下降。寄生虫的大约潜伏期为 4-5 天（感染后 90 小时和粪便中的组织学观察到未孢子卵囊，第 5 天），潜伏期持续到感染后第 12 天。为了表征艾美耳球虫属的内源性发育，在整个估计的潜伏期内，每 6 小时在肠道（包括盲肠和直肠）的 8 个区域收集组织。观察到寄生虫感染十二指肠降段和升段、空肠中段、回肠近端和远端以及盲肠。确定的内源阶段包括细胞内子孢子、3代子生殖阶段和配子生殖阶段。线粒体基因组 (GenBank MW934555) 和核18S核糖体 DNA (GenBank MW934259) 的序列是使用聚合酶链式反应扩增进行桑格测序获得的，这些序列在 GenBank 上所有已发布的序列中都是独一无二的。分子数据与艾美耳球虫的独特生物学相结合。从 chukar 鹧鸪群中分离出来，支持这种球虫对科学来说是新的。