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Prevalence of allergic and autoimmune pathologies is clearly increasing in developed countries. This has been attributed to a decreased exposure to certain microorganisms and been referred as hygiene hypothesis. In this study we evaluated if a previous infection with Strongyloides venezuelensis would alter the progression of experimental autoimmune encephalomyelitis (EAE) in Lewis rats. Animals were initially infected with 4000 L3 infective larvae of S. venezuelensis by subcutaneous route. Encephalomyelitis was then induced during the acute phase of the infection by immunization with myelin basic protein emulsified with Complete Freund's Adjuvant plus Mycobacterium butyricum. Previous infection downmodulated cytokine production but did not change clinical and histopathological EAE manifestations. Cytometric analysis with antibodies specific for CD4+CD25+Foxp3+ regulatory T cells indicated that infection also did not alter the frequency of these cells in spleen and regional lymph nodes. This finding could partly explain the failure of this worm to avoid EAE progression. Altogether these results demonstrated that infection with S. venezuelensis was not able to modify EAE progression in Lewis rats. In the context of the hygiene hypothesis, these results reinforce the necessity of a comparative study among different helminth species to identify the ones with immunoregulatory competence.

Background: Helminths is a endoparasites that cause the major losses for profitable sheep production in Brazil. The increased development of resistant strains of endoparasites have enforced the search for sustainable alternatives. The aim of this paper was to provide information about endoparasites control with banana leaves in infected sheep as alternative control strategies and see its viability. Materials and Methods: In this study, we performed two trials to investigate the anthelmintic properties of banana leaves on endoparasites in sheep. In Trial 1, twelve sheep were artificially infected with Trichostrongylus colubriformis; in Trial 2, eleven sheep were artificially infected with Haemonchus contortus. Clinical examinations, packed cell volume, total protein, faecal egg counts (FECs) and egg hatchability tests (EHTs) were performed. At the end of the trials, the sheep were humanely slaughtered, and total worm counts were performed. Results: In Trial 1 and 2, no significant FEC decreases were note but significant diference in EHTs were observed. Total worm counts, clinical and haematological parameters did not reveal significant changes between the treatment and control groups. These results suggest that feeding dried ground banana plant leaves to sheep may reduce the viability of Trichostrongylus colubriformis eggs, and this anthelmintic activity is potentially exploitable as part of an integrated parasite management programme. Conclusion: However, further investigation is needed to establish the optimal dosage, develop a convenient delivery form and confirm the economic feasibility of using banana plantation byproducts as feed for ruminant species.