Background: Depending mainly on Praziquantel (PZQ) for treatment of schistosomiasis poses a great challenge in terms of effectiveness and resistance. Nanoscale particles formed by metals as iron nanoparticles (INPs) have recently gained approval from the Food and Drug Administration for use as therapeutic agents. Therefore, INPs application as potential therapeutic agents against schistosomiasis may give promising results. Objective: The present study aimed at assessing the efficacy of INPs; iron oxide or magnetite INPs (MNPs) and zero-valent INPs (ZV-INPs) on S. mansoni using parasitological and histopathological parameters. Material and Methods: In the current study, MNPs and ZV-INPs were prepared by biogenic synthesis and were given to mice orally on the 42 nd day post infection (dpi) with S. mansoni in a dose of 10 mg/kg for four consecutive doses. The therapeutic efficacy was assessed using parasitological (mortality rate, adult worm load as well as female fecundity) and histopathological parameters (tissue egg count in both liver and intestine) in comparison to untreated and PZQ treated control groups. Results: Results revealed that ZV-INPs have a significant effect in decreasing both tissue egg count and hepatic granulomata size. While the MNPs have a significant effect against the total and female worms burden, tissue egg counts, female fecundity, and number of liver granuloma. Conclusion: Herein, it was concluded that both types of INPs used in the study are potentially effective anti-schistosomal agents.

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The tight relationship between immunity and retinoid levels provides evidence on the critical role of retinoic acid (RA) in regulating immune activity, especially the mucosal one. Mucosal immune response is the key for determination of the outcome of infection, particularly against intracellular mucosal pathogens such as Toxoplasma gondii, where it plays a crucial role as a sentinel against parasite invasion. Herein, the immunomodulatory adjuvant role of RA was evaluated for prophylactic vaccination against chronic Toxoplasma infection. A quantity of 15 µg of RA pre-encapsulated with lipid-based nanoparticles (SLNs) was intranasally used in three doses, two weeks apart, as an adjuvant to the Toxoplasma lysate antigen (TLA). Afterward, mice were infected with 20 cysts of T. gondii (ME49 strain) and were sacrificed at the 4th week post-infection. Parasitological, immunological, biochemical, and histopathological studies were applied as vaccine efficacy measures. The protective role of the tested vaccine was noted using the statistically marked reduction in brain cyst count, accompanied by remarkable levels of protective IFN-γ and antibodies, with amelioration of infection-induced oxidative stress and brain pathology. Ultimately, this experiment outlined the prospective role of a novel, natural, nano-encapsulated and mucosal vaccine adjuvant RA-SLNs as a propitious candidate against chronic toxoplasmosis.

Schistosomiasis is the second major parasitic disease in the world after malaria. It affects 201.5 million cases in Africa alone. The aim of this research was to explore alternative vaccination strategies against experimental schistosomiasis mansoni. We assessed the effect of cercarial transformation fluid (CTF) singly and in combination with crude cercarial antigen (CCA) using alum as an adjuvant. The combined antigens gave the best results, as evidenced by a significant reduction in the worm load (62.07%), tissue egg count (78.16%, 86.46%) in liver and intestine respectively, and hepatic granuloma size (29.96%). Scanning electron microscopy revealed changes in the tegument, in the form of roughness and appearance of vesicles and furrows between the tegumental tubercles. Also, resorption of the ventral sucker and dimples replacing its spines were observed. The female tegument was irregular and its posterior end showed loss of spines and sensory bulbs. Moreover, there was a significant decrease in liver enzymes (alanine transaminase (ALT) and aspartate transaminase (AST)) compared to infected control mice. A significant elevation in CD4+T-lymphocytes, denoting amelioration of the immune status, in mice that received combined antigens was also observed. It can be concluded that combined antigens demonstrate potential as a vaccine against Schistosoma mansoni.