Related Experiment Videos
[Further studies on the mongolian jird model of Giardia lamblia]
Abstract:
Seventy-seven Meriones unguiculatus were inoculated intra-esophageal with Giardia lamblia cysts isolated from the stool of a Giardia infected child. Correlation between oral dosage, course of infection, trophozoite distribution and the pathological changes in the small intestine of the infected jirds were studied. One (12.5%) of eight animals became infected with only 5 cysts. 10(4) cysts/jird or more was infective to nearly all the animals. Most of the infected animals (83%) excreted cysts and/or trophozoites intermittently. The extent of trophozoite colonization and their distribution in the small intestine varied with the time of infection, but not with the number of Giardia found in the feces. There was no direct correlation between the size of inoculum and the course of infection, the fecal output of cysts and/or trophozoites, or the intensity of pathological changes in the small intestine. The histopathological lesions induced by G. lamblia included cellular infiltration of the mucosa of the small bowel, nodular lymphoid hyperplasia, edema of the lamina propria and increase in mucous secretion. Necrobiosis and shedding of the epithelium was evident, and the mitotic figures of intestinal crypt increased significantly. The reduction of the villi to crypts ratio may indicate that the villi of small intestine were covered by relatively immature enterocytes, which may, partially, account for the malabsorption in giardiasis (Figs. 1-3).
Insights
Giardia lamblia infection in jirds shows that even a small dose can infect, but higher doses don't worsen symptoms or pathology. Intestinal damage includes inflammation and altered cell turnover, potentially causing malabsorption.
Area of Science:
- Parasitology
- Gastroenterology
- Pathology
Context:
- Giardia lamblia is a common intestinal parasite causing giardiasis.
- Understanding the dose-response relationship and pathological effects is crucial for disease management.
Purpose:
- To investigate the correlation between oral Giardia lamblia dosage and infection course, trophozoite distribution, and small intestine pathology in Meriones unguiculatus.
- To determine the minimum infective dose and assess pathological changes in relation to inoculum size.
Summary:
- Meriones unguiculatus were inoculated with Giardia lamblia cysts. Infectivity was high with 10(4) cysts/jird or more, with intermittent cyst/trophozoite excretion in 83% of infected animals.
- Trophozoite colonization varied with infection time but not fecal Giardia counts. No direct correlation was found between inoculum size and infection course, fecal output, or pathology.
- Histopathological lesions included mucosal infiltration, lymphoid hyperplasia, edema, increased mucus, epithelial shedding, and increased crypt mitotic figures, with a reduced villi-to-crypt ratio suggesting immature enterocytes and potential malabsorption.
Impact:
- This study elucidates the pathogenesis of giardiasis in a rodent model, highlighting specific histopathological changes in the small intestine.
- Findings contribute to understanding malabsorption mechanisms in giardiasis and inform potential therapeutic strategies.