Yabsley Michael J, Gibbs Samantha E J
Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602, USA.
J Parasitol. 2006 Apr;92(2):385-8. doi: 10.1645/GE-592R.1.
The renal parasite Eimeria auritusi has caused several mortality events in double-crested cormorants (DCC; Phalacrocorax auritus) in the Midwest and southeastern United States. This parasite has only been detected during large-scale outbreaks, and its presence and prevalence in healthy populations of cormorants is unknown. In this study, 80 DCC were collected from the Chattahoochee River near Fort Gaines, Georgia, and examined for kidney and intestinal coccidia. Eighteen (22.5%) and 56 (70%) of the DCC were positive for E. auritusi and a new species of intestinal Eimeria, respectively. Oocysts of the new intestinal Eimeria species had a thin colorless wall, were ovoid with rare bumps on the outer surface, and measured 17.1 microm +/- 1.5 x 14.7 microm +/- 1.0 (16-18.5 x 13-17), with an average length:width ratio of 1.17 microm (1.03-1.29). A prominent micropyle (4-4.5 microm) was present, and a large oval-to-round polar body (2.5 microm) was located beneath the micropyle. Sporocysts were ovoid and measured 9.6 microm +/- 0.6 x 5.9 microm +/- 0.5 (8.5-10.5 x 5-6.5), with an average length:width ratio of 1.63 (1.3-1.82) with small stieda body present. Amplification and sequencing of a fragment of the 18S rRNA gene indicated that the 2 DCC Eimeria species and 2 Eimeria species from cranes were in a separate group from other Eimeriidae. These data indicate that E. auritusi and this new species of intestinal Eimeria are prevalent in this apparently healthy DCC population. The cause of renal coccidiosis outbreaks in other populations of cormorants is unknown but could be due to crowding or stress during the winter months or some other associated pathogen or immunosuppressor that might predispose individuals to clinical disease.
肾寄生艾美耳球虫（Eimeria auritusi）已在美国中西部和东南部的双冠鸬鹚（DCC；Phalacrocorax auritus）中引发了多起死亡事件。这种寄生虫仅在大规模疫情爆发期间被检测到，其在健康鸬鹚种群中的存在情况和流行程度尚不清楚。在本研究中，从佐治亚州盖恩斯堡附近的查塔胡奇河采集了80只双冠鸬鹚，并对其肾脏和肠道球虫进行了检查。分别有18只（22.5%）和56只（70%）双冠鸬鹚的肾脏和肠道中检测到了耳氏艾美耳球虫和一种新的肠道艾美耳球虫。新的肠道艾美耳球虫种类的卵囊壁薄且无色，呈椭圆形，外表面有稀少的凸起，大小为17.1微米±1.5×14.7微米±1.0（16 - 18.5×13 - 17），平均长宽比为1.17微米（1.03 - 1.29）。有一个明显的卵孔（4 - 4.5微米），在卵孔下方有一个大的椭圆形至圆形的极体（2.5微米）。孢子囊呈椭圆形，大小为9.6微米±0.6×5.9微米±0.5（8.5 - 10.5×5 - 6.5），平均长宽比为1.63（1.3 - 1.82），有小斯氏体。对18S rRNA基因片段进行扩增和测序表明，双冠鸬鹚的这两种艾美耳球虫和鹤的两种艾美耳球虫与其他艾美耳科动物属于不同的类群。这些数据表明，耳氏艾美耳球虫和这种新的肠道艾美耳球虫在这个看似健康的双冠鸬鹚种群中很普遍。其他鸬鹚种群中肾球虫病爆发的原因尚不清楚，但可能是由于冬季拥挤或应激，或者是其他一些相关病原体或免疫抑制剂，这些因素可能使个体易患临床疾病。
