Mathis A, Michel M, Kuster H, Müller C, Weber R, Deplazes P
Institute of Parasitology, University of Zürich, Switzerland.
Parasitology. 1997 Jan;114 ( Pt 1):29-35. doi: 10.1017/s0031182096008177.
The microsporidian Encephalitozoon cuniculi can infect a wide variety of mammals including man. In this study, E. cuniculi isolates of animal origin were compared with 6 isolates obtained from HIV-infected patients. Based on results of Western blot analysis, random amplified polymorphic DNA (RAPD) and the sequence of the rDNA internal transcribed spacer (ITS) the isolates were classified into 3 groups with the repeated element 5'GTTT-3' in the ITS being a reliable genetic marker. Five isolates from Swiss patients were found to be homologous to isolates from Swiss rabbits (strain I). The sixth isolate from a patient from Mexico differed by all methods and could be attributed to E. cuniculi strain III that has been described from 2 dogs from the USA. All of these isolates were distinguished from isolates from blue foxes from Norway (strain II). Intraspecific nucleotide divergence of the SSU rRNA gene of E. cuniculi belonging to the 3 strains was in the same low range (0.00-0.15%) as was found for the corresponding sequence of 2 E. hellem isolates. Groups of 2 rabbits were infected by oral inoculation of 10(7) E. cuniculi spores (2 isolates from strain I of human and rabbit origin, 1 from strain III) as shown by antibody responses and the re-isolation of the parasites from brain material. The results provide further evidence that per oral transmission of the parasite between various hosts is feasible.
微小孢子虫兔脑炎微孢子虫可感染包括人类在内的多种哺乳动物。在本研究中，将动物源的兔脑炎微孢子虫分离株与从HIV感染患者中获得的6株分离株进行了比较。基于蛋白质免疫印迹分析、随机扩增多态性DNA（RAPD）以及核糖体DNA内部转录间隔区（ITS）序列的结果，这些分离株被分为3组，ITS中重复元件5'GTTT-3'是一个可靠的遗传标记。发现来自瑞士患者的5株分离株与来自瑞士兔（I株）的分离株同源。来自墨西哥一名患者的第6株分离株在所有方法上均有差异，可归为兔脑炎微孢子虫III株，该株已从美国的2只狗中分离得到。所有这些分离株均与来自挪威蓝狐的分离株（II株）不同。属于这3个菌株的兔脑炎微孢子虫小亚基核糖体RNA（SSU rRNA）基因的种内核苷酸差异处于与2株海伦脑炎微孢子虫相应序列相同的低水平范围（0.00 - 0.15%）。通过抗体反应以及从脑材料中再次分离出寄生虫，证实了两组兔子经口接种10⁷个兔脑炎微孢子虫孢子（2株来自人和兔源的I株，1株来自III株）后被感染。这些结果进一步证明了该寄生虫在不同宿主之间经口传播是可行的。
