Background: The present study aimed to assess the therapeutic effect of chitosan nanoparticles and metronidazole against Giardia lamblia as well as evaluate the efficacy of loading metronidazole on chitosan nanoparticles. Methods: This study was carried out at medical Parasitology Department, Faculty of Medicine, Zagazig University and Theodor Bilharz Research institute (TBRI) from February 2019 to February 2020 on 45 hamsters. They were divided into 5 groups 9 hamsters each: Group A non-infected hamsters, Group B infected control group, Group C, D and E infected with G. lamblia and treated with Chitosan nanoparticles (CsNPs), metronidazole (MTZ) and metronidazoleloaded chitosan nanoparticles (MTZ-CsNPs) respectively. Results: The highest percentage of reduction in the Giardia cyst and trophozoite counts were in group that received MTZ-CsNPs (94.69%, 94.29%). Lower percentages of reduction were recorded for MTZ treated group (90.15%, 89.52%) and CsNPs treated group (63.64%, 75.24%). Histopathological examination showed marked healing of intestinal mucosa after treatment with MTZCsNPs. Conclusion: CsNPs showed a therapeutic effect against Giardia infection in hamsters. Loading of metronidazole on chitosan nanoparticles enhanced therapeutic effect of both CsNPs as well as metronidazole.

Background and study aim: Toxoplasma gondii is a globally distributed parasite that causes oxidative stress as a part of the mechanism of neuropathology. The currently available treatments for toxoplasmosis are of limited efficacy because of its distinct pathophysiology. This study aimed to assess the anti-inflammatory and antioxidant effects of Lepidium sativum seed extract, olive leaves extract, resveratrol, and Eucalyptus either as a monotherapy or in combination with pyrimethamine-sulfadiazine in experimental toxoplasmosis by histopathological and immunohistochemical studies. Patients and Methods: One-hundred-seventy-six Swiss albino mice were divided into eleven experimental groups (16 mice each) as follows Group (1) Control non-infected, Group (2) Control infected, Group (3) infected and treated with pyrimethamine-sulfadiazine, Group (4) infected and treated with RSV, Group (5) infected and treated with Eucalyptus, Group (6) infected and treated with Lepidium sativum, Group(7) infected and treated with olives leaves extract, Group (8) infected and treated with pyrimethamine-sulfadiazine and RSV, Group(9) infected and treated with pyrimethamine-sulfadiazine and Eucalyptus, Group (10) infected and treated with pyrimethamine-sulfadiazine and Lepidium sativum, Group (11) infected and treated with pyrimethamine-sulfadiazine and olives leave extract. Results: Histopathological examination of liver and brain tissues displayed marked improvement in all treated groups with a significant effect on the expression of iNOS and NSE, mainly in olives leaves extract treated groups. Conclusion: Olive leaf extract, Lepidium sativum seed extract, resveratrol, and Eucalyptus can be promising efficient natural alternatives that can ameliorate the histopathological changes and oxidative stress triggered by the parasite during Toxoplasma gondii infection.

Cryptosporidiosis is a major cause of human diarrhea worldwide in immunocompromised individualscausing severe, chronic and possibly life threatening diarrhea. Nitazoxanide (NTZ) hasbeen approved for treatment of diarrhea in immunocompetent children and adults, but not effectivein immunosuppressed individuals. The present study evaluated the effect of NTZ-loadedchitosan nanoparticles on intestinal dysplastic changes of experimental Cryptosporidium infectionin immunosuppressed murine model using parasitological, histopathological and immunohistochemicalstudies. Fifty immunosuppressed male mice, divided into 5 groups (10 each) asfollowing: G1: non infected control, G2: non-treated infected control, G3: infected then treatedby nitazoxanide, G4: infected then treated by nitazoxanide loaded on chitosan nanoparticles, G5:infected then treated by chitosan nanoparticles (CS NPs). NTZ loaded on chitosan NPs treatedmice showed the highest significant reduction in oocysts shedding, a remarkable improvement inhistopathological changes and the least expression of cyclin D1 marker denoting the best protectionpresented to intestinal dysplastic changes caused by Cryptosporidium infection of the intestinefollowed by treatment with NTZ then by treatment with CS NPs alone that showed someimprovement in histopathological and immunohistochemical changes.