Giardia duodenalis pathogenicity on immunosuppressed animal model.

Giardiasis is the major water-borne diarrheal disease present worldwide caused by the common intestinal parasite, Giardia duodenalis. This work aims to investigate the effect of G. duodenalis infection pathogenicity in immunosuppressed animals through histopathological examination. A total of 45 BALB/c mice were divided into four groups; G1 (negative control), G2 (healthy animals exposed to Giardia); G3 (immunosuppressed animals exposed to Giardia), and G4 (non-exposed immunosuppressed animals). Our study revealed that G3 was the most affected group with an infection rate of 100%. The animals showed general weakness, soft stool, and high death rate with severe histopathological changes in the duodenum and mild degenerative changes in hepatic tissues. In G2, the maximal lesions in both duodenum and liver were on the 11th day. We spotted damage in the villi, edema in the central core, and submucosa, in addition to increased cellular infiltration with inflammation in lamina propria. The presence of the parasites within the villi and the lumen was clear. Most of the hepatocytes revealed hydropic and fatty changes, also dilated congested central veins and edema were observed. G3 changes were more intense than G2 with massive Giardia trophozoites between the intestinal villi, lumen, and extensive fatty liver degeneration. Immune suppression plays a significant role in the severity of injury with the Giardia parasites in duodenum and liver cells.

Giardia duodenalis pathogenicity on immunosuppressed animal model

@#Giardiasis is the major water-borne diarrheal disease present worldwide caused by the common intestinal parasite, Giardia duodenalis. This work aims to investigate the effect of G. duodenalis infection pathogenicity in immunosuppressed animals through histopathological examination. A total of 45 BALB/c mice were divided into four groups; G1 (negative control), G2 (healthy animals exposed to Giardia); G3 (immunosuppressed animals exposed to Giardia), and G4 (non-exposed immunosuppressed animals). Our study revealed that G3 was the most affected group with an infection rate of 100%. The animals showed general weakness, soft stool, and high death rate with severe histopathological changes in the duodenum and mild degenerative changes in hepatic tissues. In G2, the maximal lesions in both duodenum and liver were on the 11th day. We spotted damage in the villi, edema in the central core, and submucosa, in addition to increased cellular infiltration with inflammation in lamina propria. The presence of the parasites within the villi and the lumen was clear. Most of the hepatocytes revealed hydropic and fatty changes, also dilated congested central veins and edema were observed. G3 changes were more intense than G2 with massive Giardia trophozoites between the intestinal villi, lumen, and extensive fatty liver degeneration. Immune suppression plays a significant role in the severity of injury with the Giardia parasites in duodenum and liver cells.

Morpho-Physiological and Biochemical Criteria of Acanthamoeba spp. Isolated from the Egyptian Aquatic Environment.

BACKGROUND: The free-living amoebae Acanthamoeba spp., have been recognized as etiologic agents of amoebic encephalitis, keratitis, otitis, lung lesions and other skin infections mainly in immuno-compromised individuals. In this study, morpho-physiological and biochemical characterization of Acanthamoeba strains isolated from the Egyptian aquatic environment were surveyed. METHODS: Some Acanthamoeba species were cultivated on non-nutrient agar. Isolated strains of Acanthamoeba were identification based on the morphology of trophic and cyst forms in addition to temperature and osmo-tolerance assays. Biochemical characterization of the isolated amoeba strains was performed using quantitative assay as well as qualitative determination of proteolytic activity in zymograph analysis. RESULTS: Potentially pathogenic Acanthamoeba species were isolated from all of the examined water sources. Colorimetric assays showed protease activity in the heat-tolerant isolates of Acanthamoeba. All pathogenic isolates of Acanthamoeba exhibited higher protease activity than did the non-pathogenic ones. The zymographic protease assays showed various banding patterns for different strains of Acanthamoeba. CONCLUSION: The incidence and prevalence of the pathogenic Acanthamoeba species in the aquatic environment using parasitological and biochemical diagnostic tools will provide baseline data against which the risk factors associated with waterborne transmission can be identified.