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

Modulatory role of immunization with secretory-excretory products of schistosoma haematobium eggs on morbidity in infected hamsters

A variety of secretory-excretory products [SEPs] from different stages of Schistosoma have been identified to induce a level of host-protective immune responses with amelioration of morbidity. Identification of SEPs complex components can be expected to facilitate discovery of new therapeutic drug targets and new diagnostic markers for schistosomiasis control. The present study was undertaken to evaluate the possible anti-morbidity effects of SEPs of S. haematobium eggs twelve weeks after exposure to infection. The liver and intestinal tissues of infected hamsters were selected for evaluation as in the murine models the urinary bladder exhibits minimal morbidity in response to S. haematobium infection. The experimental design included three groups of 10 hamsters each; SEPs immunized group, infected immunized group and infected control group. Multiple small doses of purified S. haematobium eggs SEPs were injected intra-peritoneally, followed 2 weeks later with 2 booster doses at weekly intervals. Animals were infected with S. haematobium cercariae 1 week following last booster immunization dose. All animals were sacrificed 12 weeks PI. Assessment of the modulatory role of SEPs immunization including worm burden, tissues egg loads, oogram pattern and histopathological examination of liver and intestinal tissues were carried out. Total and subclasses of anti SEPs of S. haematobium eggs IgG, IgM, IgG2 and polyvalent immunoglobulins [Igs] were measured using indirect ELISA at weeks 3, 6 and 9 post-infection [PI]. Immunization with SEPs of S. haematobium eggs produced significant reduction in worm load [61.37%], reduction in tissue egg loads [54.85% and 41.57% for hepatic and intestinal ova, respectively]; decreased percent of immature stages and increase in the percent of dead ova in oogram pattern. Pathological examination also revealed significant reduction in number of hepatic granuloma [46.06%]. At 3, 6 and 9 weeks PI, the level of Igs especially IgG was significantly higher in the infected immunized group, compared to both control groups, reached a peak value at 6 weeks PI [1.6] and remained elevated till the end of the experiment with slightly decreasing tendency at 9 weeks PI [1.3]. This study could represent an immunization model as a trial to decrease severe morbidity of schistosomiasis haematobium which may be aggravated by serious sequels