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

Oogram pattern, egg load and hatchability of eggs in mixed infection of Schistosoma mansoni and Schistosoma haematobium in hamster

Laboratory bred hamsters, weight 125-185 g each, were examined in this study and classified into three groups. In the first group, 15 hamsters were exposed simultaneously to 100 cercariae of S. Mansoni and 100 cercariae of S. haematobium. Experimentally infected hamsters and their controls were scarified at 7 and 10 weeks postinfection. In the second group, 20 hamsters were exposed each to 100 cercariae of S. mansoni for 7 weeks then superinfected with 100 cercariae of S. haematobium and scarified 25 days later. Their controls were 20 hamsters exposed to 100 cercariae of S. mansoni. In the third group, 20 hamsters exposed each to 100 cercariae of S. Haematobium for 10 weeks, then superinfected each with 100 cercariae of S. Mansoni and scarified 21 days post challenge infection. Their controls infected with 100 cercariae of S. Haematobium. In mixed infection with Schistosoma mansoni and S. haematobium in hamsters, either simultaneously or after the full maturation of an initial infection with either schistosome species, a high level of acquired resistance was observed. The degree of immunity was magnified by the significant reduction in the number of eggs per gram tissue and hatchability of mature eggs. Some disturbance was also observed in the oogram pattern