Schistosomiasis, also known as snail fever or bilharziasis, is a worm infection caused by trematode called schistosomes that affects humans and animals worldwide. Schistosomiasis endemically exists in developing countries. Inflammatory responses elicited in the early phase of infection represent the rate limiting step for parasite migration and pathogenesis and could be a valuable target for therapeutic interventions. Prostaglandin E2 (PGE2) and interleukin (IL)-10 were found to be differentially affected in case of immune-modulation studies and cytokine analysis of hosts infected with either normal or radiation-attenuated parasite (RA) which switches off the development of an effective immune response against the migrating parasite in the early phase of schistosomiasis. Normal parasites induce predominantly a T helper 2 (Th2)-type cytokine response (IL-4 and IL-5) which is essential for parasite survival; here, we discuss in detail the downstream effects and cascades of inflammatory signaling of PGE2 and IL10 induced by normal parasites and the effect of blocking PGE2 receptors. We suggest that by selectively constraining the production of PGE2 during vaccination or therapy of susceptible persons or infected patients of schistosomiasis, this would boost IL-12 and reduce IL-10 production leading to a polarization toward the anti-worm Thl cytokine synthesis (IL-2 and Interferon (IFN)-γ).

The present study is aimed at assessing the effectiveness of solar drying process in terms of helminth egg reduction in sewage sludge (SS) generated from an activated sludge wastewater treatment plant (WWTP) in Marrakesh city (Morocco). It is also engaged to highlight a synergic effect of liming (1% CaO) and solar drying on helminth egg reduction. The solar drying process was conducted for 45 days, in summer under a semi-arid climate in a pilot scale polycarbonate-based tunnel (2 m³). Before undergoing solar drying process, data showed an important load of helminth eggs including Ascaris sp., Schistosoma spp., Capillaria spp., Trichuris spp., Ankylostome spp., Toxocara spp., and Taenia spp. in limed sludge (LS) and non-limed sludge (NLS) (15.2 and 17.9 eggs/g, respectively). Ascaris eggs were the most abundant (11.2 and 13.5 eggs/g in LS and NLS, respectively). By the end of the solar drying process, a considerable removal of the total helminth eggs was recorded in LS and NLS (92.8% and 91.6%, respectively). A complete removal of Schistosoma spp., Capillaria spp., Trichuris spp., Toxocara spp. and Taenia spp. was noted in LS and NLS. In the case of Ankylostome spp., data showed a total removal in LS and 81% in NLS; however, the final load is in agreement with the standards (0.4 egg/g). As for Ascaris spp., neither liming nor solar drying process allowed a complete removal (91% and 90% in NLS and LS, respectively) and the final load (1.1 egg/g) does not fulfill the WHO requirements for an agricultural use. Principal component analysis (PCA) demonstrated a negative correlation between dry matter (DM) content (hence temperature) and helminth egg concentration. No significant synergic effect of liming and solar drying process was showed by statistical analysis. This is substantiating that temperature is the key parameter involved in helminth egg removal while undergoing solar drying of SS.

The prevalence and the identification of the helminth eggs load of raw sewage sludge was assessed of three different wastewater treatment systems. The results showed a variety of parasite species with following average concentrations; five taxa belonging to three classes nematodes, cestodes and trematodes were inventoried. The class of nematodes is the most diverse with 5 taxa. It is represented by the eggs of Ascaris sp., Capillaria sp., Trichuris sp., Toxocara sp., and Ankylostome sp., then comes the cestodes class, this is represented by the eggs of Tænia sp. The trematode class is represented by Schistosoma sp. The lagooning station of Chichaoua shows the highest load 7 species with Ascaris 21 eggs/g; Capillaria sp., 11 eggs/g; Trichuris sp., 6 eggs/g; Toxocara sp., 2 eggs/g and Ankylostome sp., 1 egg/g; Taenia sp., 2eggs/g; and Schistosoma sp., 1 egg/g. Infiltration-percolation sludge show the presence of 4 species of helminths eggs in sludge from anaerobic settling with different rates: 15 eggs/g for Ascaris sp., 15 eggs/g for Trichuris sp., 13 eggs/g for Capillaria sp., and 8 eggs/g for Taenia sp. However, in sand filter pool, the sludge helminth eggs load was decreased by 47% of Ascaris sp., 85% of Capillaria sp., and 75% of Taenia sp., Nevertheless, an increase of Trichuris eggs load was noted in the second sludge by 17%. Five helminth eggs was detected in primary sludge coming from decantation pools in activated sludge plant in Marrakech, that is Ascaris sp., with a load of 16 eggs/g; Capillaria sp., with 3 eggs/g, Trichuris eggs with 2 eggs/g; Taenia sp., with 4 eggs/g; and Schistosoma sp., with 2 eggs/g. The abatement load of Ascaris sp. with 81% and Schistosoma and Taenia sp., with 100% was noted in biological sludge. Nevertheless, an increase load of Capillaria and Trichuris eggs 81% and 75% respectively was observed in this sludge coming from biological pools. The distribution of parasitic helminth eggs is linked to the differences in demographic and socio-economic status, seasonal variation, physico-chemical characteristic of helminth eggs, and the purification wastewater system performance.