Majewska A C
Zakład Biologii i Parazytologii Lekarskiej, AM im. K. Marcinkowskiego, Poznań.
Wiad Parazytol. 1994;40(1):3-9.
In man, as well as in many species of vertebrates there exist several populations of Giardia duodenalis group which, though morphologically indistinguishable, show different level of heterogenicity in several characteristics, a.o. in surface antigens, isoenzyme make-up, RFLP, invasiveness for different hosts or pattern of experimental infection. Also the clinical observations in man distinctly suggested that G. intestinalis comprises several different populations. In the course of giardiasis apparent variability in clinical manifestations can be observed. In many patients the infection is symptomless and resolves spontaneously and in some others--variable intensity of symptoms is observed. Most likely both the parasite's characteristics and the host's feature will determine the clinical character of infection. It is well known that in some cases it is the host that responsible for the symptoms of the infection. Thus, for instance, clinical giardiasis links with immunodeficiency, malnutrition or young age. There are also evidences that some Giardia isolates have enhanced potency to provoke the disease of the host. It is considered that the variable pattern of the infection may be related to three different factors in host-parasite relationship: extra- and intrapopulation variability of Giardia isolates, the microenvironmental factors of the host's intestine, and the variable immune response of the host. The author describes data on the two first factors.
在人类以及许多脊椎动物物种中，存在几种十二指肠贾第虫组群，它们虽然在形态上无法区分，但在几个特征方面表现出不同程度的异质性，例如表面抗原、同工酶组成、限制性片段长度多态性、对不同宿主的侵袭性或实验感染模式。对人类的临床观察也清楚地表明，肠贾第虫包括几个不同的种群。在贾第虫病的病程中，可以观察到临床表现明显的变异性。许多患者的感染无症状且可自发缓解，而在其他一些患者中，则观察到症状强度各异。很可能寄生虫的特征和宿主的特征都会决定感染的临床特征。众所周知，在某些情况下，宿主是感染症状的起因。例如，临床贾第虫病与免疫缺陷、营养不良或年幼有关。也有证据表明，一些贾第虫分离株引发宿主疾病的能力增强。人们认为，感染模式的变化可能与宿主 - 寄生虫关系中的三个不同因素有关：贾第虫分离株的种群间和种群内变异性、宿主肠道的微环境因素以及宿主的可变免疫反应。作者描述了关于前两个因素的数据。
