Cevallos A, Carnaby S, James M, Farthing J G
Department of Gastroenterology, St Bartholomew's Hospital, London, England.
Gastroenterology. 1995 Sep;109(3):766-73. doi: 10.1016/0016-5085(95)90383-6.
BACKGROUND & AIMS: The factors that determine the severity of giardiasis are poorly understood. Host factors are important, but parasite virulence may also play a role. The aim of this study was to compare the apparent virulence of three genotypically different Giardia isolates (PO1, VNB3, and WB).
Infection rates, parasite loads, structural damage, disaccharidase activity, and water and electrolyte absorption were observed at 10 days after inoculation in a neonatal rat model of infection.
DNA fingerprinting showed differences between isolates studied. The infective rate varied between 67% and 100%. There were no differences in intestinal parasite load. Infection with strains PO1 and WB, but not with VNB3, was associated with a reduction in villus height. There was precocious expression of sucrase at 10 days after inoculation in all infected groups. Water absorption of a plasma electrolyte solution was decreased in VNB3-infected animals when compared with PO1- and WB-infected animals and controls. Water absorption and lactose hydrolysis were impaired during perfusion with a lactose-containing solution in all infected groups.
Three genotypically different Giardia isolates that infect neonatal rats with the same trophozoite load differ in their ability to cause functional mucosal damage. Infection with Giardia lamblia induced precocious expression of sucrase activity and impaired mucosal absorption.
目前对决定贾第虫病严重程度的因素了解甚少。宿主因素很重要，但寄生虫毒力可能也起作用。本研究的目的是比较三种基因不同的贾第虫分离株（PO1、VNB3和WB）的表观毒力。
在新生大鼠感染模型中，接种后10天观察感染率、寄生虫负荷、结构损伤、双糖酶活性以及水和电解质吸收情况。
DNA指纹图谱显示所研究的分离株之间存在差异。感染率在67%至100%之间。肠道寄生虫负荷无差异。PO1和WB株感染，但VNB3株未感染，与绒毛高度降低有关。所有感染组在接种后10天均出现蔗糖酶早熟表达。与PO1和WB感染动物及对照组相比，VNB3感染动物对血浆电解质溶液的水吸收降低。在所有感染组中，含乳糖溶液灌注期间水吸收和乳糖水解均受损。
三种基因不同的贾第虫分离株，以相同滋养体负荷感染新生大鼠，在引起功能性黏膜损伤的能力方面存在差异。蓝氏贾第鞭毛虫感染诱导蔗糖酶活性早熟表达并损害黏膜吸收。
