Zieman Elliott A, Nielsen Clayton K, Jiménez F Agustín
Department of Zoology, Southern Illinois University Carbondale, 1125 Lincoln Dr. Carbondale, IL, 62901-6501, United States.
Department of Zoology, Southern Illinois University Carbondale, 1125 Lincoln Dr. Carbondale, IL, 62901-6501, United States; Department of Forestry, Southern Illinois University Carbondale, 1205 Lincoln Dr., Carbondale, IL, 62901, United States; Cooperative Wildlife Research Laboratory, Southern Illinois University Carbondale, 1125 Lincoln Dr., Carbondale, IL, 62901, United States.
Vet Parasitol. 2018 Mar 15;252:67-69. doi: 10.1016/j.vetpar.2018.01.022. Epub 2018 Feb 1.
Cytauxzoon felis, and the resulting disease, cytauxzoonosis, is an emerging threat to domestic cats in the Midwest and Southeastern United States. Domestic cats that survive cytauxzoonosis (or are subclinically infected) are chronically infected with C. felis, yet to date, there is no information relative to chronic infections in bobcats, the natural reservoir. Over a period of 3.5 years (2014-2017), we captured and re-captured 5 bobcats in southern Illinois. One bobcat was captured each year of trapping, 1 was caught in the first and third year and 3 were recaptured approximately 1 year apart. We screened bobcats for the presence of C. felis using a nested PCR that amplified the nuclear small subunit (SSU) 18S rRNA. In addition, we amplified and sequenced the internal transcribed spacers 1 and 2 (ITS1 and ITS2) to detect if the strains of C. felis in each bobcat were consistent over time. All bobcats were positive for C. felis at the initial and subsequent capture(s). Bobcats that were PCR-positive for C. felis had blood smears screened for the presence of C. felis; all PCR-positive bobcats had detectable parasites in blood smears. The strains of C. felis present were consistent each year in 4 of 5 bobcats indicating these bobcats remained infected during this period. One bobcat appeared to be infected with a different strain based on a polymorphism at a nucleotide in ITS1. Our study provides important details of the epizootiology of C. felis: bobcats are chronically infected and are not immune to reinfection with new strains of C. felis.
嗜吞噬细胞无形体（Cytauxzoon felis）以及由此引发的疾病——嗜吞噬细胞无形体病，对美国中西部和东南部的家猫构成了新出现的威胁。在家猫中，能够从嗜吞噬细胞无形体病中存活下来（或受到亚临床感染）的会长期感染嗜吞噬细胞无形体。然而，迄今为止，关于作为天然宿主的短尾猫慢性感染的情况尚无相关信息。在2014年至2017年的3.5年时间里，我们在伊利诺伊州南部捕获并重新捕获了5只短尾猫。每年诱捕时捕获1只短尾猫，1只在第一年和第三年被捕获，3只大约相隔1年被重新捕获。我们使用巢式PCR检测短尾猫是否存在嗜吞噬细胞无形体，该方法可扩增核糖体小亚基（SSU）18S rRNA。此外，我们还扩增并测序了内部转录间隔区1和2（ITS1和ITS2），以检测每只短尾猫体内嗜吞噬细胞无形体的菌株随时间推移是否一致。所有短尾猫在初次捕获及后续捕获时嗜吞噬细胞无形体检测均呈阳性。对嗜吞噬细胞无形体PCR检测呈阳性的短尾猫进行血涂片检查，以确定是否存在嗜吞噬细胞无形体；所有PCR检测呈阳性的短尾猫血涂片中均能检测到寄生虫。5只短尾猫中有4只体内的嗜吞噬细胞无形体菌株每年都保持一致，这表明这些短尾猫在此期间一直处于感染状态。基于ITS1中一个核苷酸的多态性，有1只短尾猫似乎感染了不同的菌株。我们的研究提供了嗜吞噬细胞无形体流行病学的重要细节：短尾猫会长期感染，并且不能免疫再次感染新的嗜吞噬细胞无形体菌株。
