Joachim Anja
Department für Pathobiologie, Institut für Parasitologie und Zoologie, Veterinärmedizinische Universität Wien, Wien, Osterreich.
Wien Klin Wochenschr. 2004;116 Suppl 4:2-6.
13 species and several genotypes have been described so far within the genus Cryptosporidium. All of them have very small stages which makes morphological differentiation difficult. The most common species is C. parvum, an enteric pathogen with a broad host spectrum including man and domestic mammals. Molecular biological studies on isolates of C. parvum and other species have shown that the species is likely not to be monophyletic but consists of several species with different host spectra. Based on DNA marker sequences one human and various animal genotypes can be differentiated. Infections of immunocompetent patients with C. parvum are usually associated with the human genotype, while infections of immunodeficient (HIV-positive) patients can also be correlated with various animal genotypes or even primarily animal pathogenic species of Cryptosporidium (e.g., C. felis). According to our current knowledge cryptosporidia are zoonotic agents; however, an animal source of human infections cannot automatically be assumed. Parasites from human patients with low infectivity for cattle and laboratory rodents could be isolated which are not considered as zoonotic.
迄今为止，隐孢子虫属已描述了13个种和若干基因型。它们所有的阶段都非常小，这使得形态学鉴别很困难。最常见的种是微小隐孢子虫，一种肠道病原体，宿主谱广泛，包括人和家养哺乳动物。对微小隐孢子虫及其他种的分离株进行的分子生物学研究表明，该种可能并非单系的，而是由几种具有不同宿主谱的种组成。基于DNA标记序列，可以区分出一种人类基因型和各种动物基因型。免疫功能正常的患者感染微小隐孢子虫通常与人类基因型有关，而免疫缺陷（HIV阳性）患者的感染也可能与各种动物基因型甚至主要是隐孢子虫的动物致病种（如猫隐孢子虫）相关。根据我们目前的认识，隐孢子虫是人畜共患病原体；然而，不能自动假定人类感染的动物来源。可以从对牛和实验啮齿动物感染性低的人类患者中分离出寄生虫，这些寄生虫不被认为是人畜共患病原体。
