Antiprotozool activity of nitazoxanide in hamsters experimentally infected with giardia lamblia or entameba histolytica

The enteropathogenic protozoa Giardia lamblia [G. lamblia] and Entamoeba histolytica [E. histolytica] are major causes of acute and chronic diarrhea in humans and various animals. Nitazoxanide is known as a drug with a broad spectrum of activity against a wide variety of intestinal parasites and enteric bacteria infecting animals and humans. The present study was carried out to evaluate the role of nitazoxanide in treatment of hamsters infected with either G. lamblia or E. histolytica, to explore its effect on infection load and histopathological changes compared to metronidazole. A highly significant reduction was found in the mean number of G. lamblia trophozoites,examined in small intestinal contents, in the group receiving metronidazole [91.91%%] and the group treated with nitazoxanide [93.23%] compared to infected control group. The reduction in cysts excreted in stool was [94.11%] and [94.55%], respectively. Administration of Nitazoxanide revealed complete disappearance of G.lamblia trophozoites, preserved villous architecture and decreased inflammatory infiltrate. Trophozoites are still present, with less numbers than infected control,after metronidazole administration with distorted villous pattern, and presence of minimal inflammatory reaction . As regards E.histolytica, the reduction in trophozoite forms,in intestinal contents, was [80.99%] in the group receiving metronidazole and [97.39%] in the group treated with nitazoxanide compared to infected control group. The reduction in the cysts of E. histolytica was [92.22%] and [97.83%], respectively. Administration of Nitazoxanide revealed also, complete disappearance of E. histolytica trophozoites, healing of mucosal ulcerations, normal villous pattern and decreased inflammatory infiltrate. Nearly similar histopathological findings were encountered with metronidazole,although improvement in protozoal burden was more pronounced with nitazoxanide. Introducing nitazoxanide as broad spectrum anti-diarrheic agent may be recommended as a drug of choice especially in cases of double infection with G. lamblia and E. histolytica. Further studies are thus needed

Ultrastructural and histopathological changes in Giardia lamblia-infected hamsters following administration of two natural compounds and/or metronidazol

The use of combined treatment of metronidazole together with arthemisia and rosemary for controlling intestinal Giardia lamblia infection has been studied. Forty laboratory-bred male hamsters were used in the current experimental study. Each hamster was infected, orally, by 10.000 Giardia lamblia cysts. Animals were divided into the following groups: [1] control infected untreated, [2] infected treated with metronidazole, [3] infected treated with arthemisia and rosemary, [4] infected receiving combined treatment of metronidazole plus arthemisia and rosemary. Each treatment was applied three weeks post-infection. Two weeks later stool analysis was performed and the number of cysts/gm stool was counted, followed by scarification of all animals. The effect of the different drug regimens on the vegetative forms [trophozoites] of the parasite was also studied. There was a highly significant cyst reduction in all treated groups compared to control animals. The highest percentage trophozoite reduction [98.7%] was found in group 4 receiving combined treatment of metronidazole plus arthemisia and rosemary, followed by group 2 [94.8%] and group 3 [62.2%]. By histology, healing of mucosal ulcerations, preserved villi and reduced chronic inflammatory infiltrate in the lamina propria were detected with combined therapy. Ultrastructurual examination of the small intestine in animals of control group showed destructed intestinal cell projections by Giardia lamblia cysts with degeneration of the intestinal submucosa. With combined treatment, complete repair of the intestinal cell projections as well as healing of the mucosa and the submucosa were noticed. Meanwhile, partial healing of destructed intestinal cell projections was observed in group 2 receiving metronidazole alone. It was concluded that the best results were obtained following combined treatment of metronidazole together with arthemisia and rosemary. This might be useful in endemic areas where people tend to develop drug resistance to the commonly used anti-Giardia lamblia preparations

Immunomodulation of pulmonary and hepatic granulomatous response in mice immunized with purified lung-stage schistosomulae antigen

The present objective was to investigate the possible effect of immunization protocol against Schistosoma mansoni infection using purified lung-stage schistosomulae antigen. Two experimental models [lung and liver] were used, each of 3 groups [Gs]: Immunized G. [10 mice] infected control G. [10 mice] and normal control G. [10 mice]. Hundred micro g of purified schistosomulae antigen followed by two booster doses each of 50 micro g antigen and at one week interval were injected intraperitoneally into Swiss albino mice three days prior to intravenous injection of 3000 viable S. mansoni eggs [lung model] or to exposure to 100 cercariae [hepatic model]. Mice were sacrificed 16 days post-injection [lung model] and 8 weeks post-infection [hepatic model]. Various parasitological parameters, histopathological assessments and immunological parameters were studied. The data revealed that immunization with purified lung-stage schistosomulae antigen induces protective effect against S. mansoni infection. The marked reduction in worm burden, egg load, granuloma diameter and collagen content were accompanied by increased percentage of degenerated ova and amelioration of the associated pathological changes in pulmonary and hepatic tissue. Increased levels of specific immunoglobulins particularly IgG and IgM and decreased ratio of T cell subsets [CD4+/CD8+] in granulomas of both models were also noticed