Visvesvara Govinda S, Moura Hercules, Leitch Gordon J, Schwartz David A, Xiao Lihua X
Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Public Health Service, Department of Health and Human Services, Atlanta, Georgia 30341-3724, USA.
Folia Parasitol (Praha). 2005 May;52(1-2):83-94. doi: 10.14411/fp.2005.011.
Brachiola algerae, a parasite of Anopheles mosquitoes, has also been isolated from a human cornea, a cutaneous nodule and deep muscle tissue. All three human isolates of B. algerae are morphologically, serologically, and genetically similar to the mosquito-derived isolates including the original isolate of Vavra and Undeen. All of these isolates grew well in mammalian cell cultures at 37 degrees C and produced spores. Transmission electron microscopy revealed that all developmental stages including meronts, sporoblasts and spores were diplokaryotic and developed in direct contact with the host cell cytoplasm, a feature characteristic of the genus Brachiola. Spores of all isolates reacted well, in the immunofluorescence assay, with the rabbit anti-B. algerae serum. In the immunoblot assay, although the overall banding patterns of the human and mosquito isolates were similar, minor differences could be discerned. Sequencing of the PCR products of the amplified SSU rRNA gene revealed the existence of two distinct genotypes; the original mosquito (Undeen) isolate belonged to genotype 1 and the isolate from cornea and that from the deep muscle biopsy to genotype 2, whereas the isolates from a mosquito and one of the other two human isolates (one from skin abscess) had both genotypes, 1 and 2. It is known that spores of mosquito-derived B. algerae can not only proliferate in mammalian cell cultures at 37 degrees C but also can infect mice when injected into footpads or deposited on the corneal surface. These observations indicate that the spores have potential to be a risk factor for humans, especially those with immunodeficiency.
阿尔及利亚短膜虫（Brachiola algerae）是按蚊的一种寄生虫，也曾从人类角膜、皮肤结节和深部肌肉组织中分离出来。阿尔及利亚短膜虫的三株人类分离株在形态学、血清学和遗传学上与源自蚊子的分离株相似，包括瓦夫拉（Vavra）和昂迪恩（Undeen）的原始分离株。所有这些分离株在37摄氏度的哺乳动物细胞培养物中生长良好并产生孢子。透射电子显微镜显示，包括裂殖体、成孢子细胞和孢子在内的所有发育阶段都是双核的，并且在与宿主细胞细胞质直接接触的情况下发育，这是短膜虫属的一个特征。在免疫荧光试验中，所有分离株的孢子与兔抗阿尔及利亚短膜虫血清反应良好。在免疫印迹试验中，虽然人类和蚊子分离株的总体条带模式相似，但可以看出一些细微差异。扩增的小亚基核糖体RNA（SSU rRNA）基因的PCR产物测序显示存在两种不同的基因型；原始的蚊子（昂迪恩）分离株属于基因型1，角膜分离株和深部肌肉活检分离株属于基因型2，而来自一只蚊子的分离株和另外两株人类分离株之一（来自皮肤脓肿）同时具有基因型1和2。已知源自蚊子的阿尔及利亚短膜虫的孢子不仅可以在37摄氏度的哺乳动物细胞培养物中增殖，而且当注射到脚垫或沉积在角膜表面时还可以感染小鼠。这些观察结果表明，这些孢子有可能成为人类尤其是免疫缺陷者的一个危险因素。
