Background: Parasitic infections of the central nervous system (CNS) are still a health problem in low- and middle-income countries and due to international travels and migration, can affect even opulent countries. Parasites can modulate host immunity to ensure their long-term survival without inflammatory symptoms, therefore infection of the brain parenchyma by Taenia solium cysticerci (parenchymal neurocysticercosis) may be asymptomatic, or on the other hand lead to severe inflammation that initiates glial activation with production of pro-inflammatory cytokines, with mild to severe neurological symptoms. Besides, when cysticerci are localized in the ventricles or in the subarachnoid space (extraparenchymal neurocysticercosis) severe symptoms and treatment difficulties occur. Summary: Here we review how the nervous, the immune and the endocrine systems interact with Taenia solium and crassiceps cystcerci and influence the course and individualities of the disease that the parasites triggers in humans and animals. In example, a clear sexual dimorphism in cysticercosis has been found in experimental models of the disease, but the influence of gender in human patients needs further investigation. The role of neurosteroids in parenchymal NCC is intriguing and could influence parasite survival and in the inflammatory reaction they cause. The synthesis of steroids by the brain cells and the cysticerci might influence the local immune response elicited by the presence of the parasites. Remarkably, cultured cysticerci can synthesize sex steroids and deoxycorticosterone (DOC) suggesting that these parasites can influence the local brain microenvironment, especially by producing dehydroepiandrosterone (DHEA), estrogens and androgens which could modify the immune response. Treatment of neurocysticercosis includes cysticidal drugs and corticosteroids intended to control the inflammation caused by the parasite, however, these steroids represent a double-edged tool due to their side effects during prolonged administration and also because of some beneficial effects for the parasite itself.
Romano et al. (Tue,) studied this question.