ABSTRACT
Hymenolepis nana is one of opportunistic parasites which is widely distributed specially amongst children and immunosuppressed patients. Some neurological manifestations can occur in immunosupressed hosts, however, their possible pathogenesis is not clearly yet idenified. The aim of the present work is to study the possible pathogenesis of the neurological manifestations in Hymenolepis nana infection. Swiss albino mice were used in this study which was divided into two groups. Group I: Mice were maintained immunocompetent [IC]. Group II: Mice were immunosupressed [IS] by subcutaneous injection of cortisone. Mice of both groups were orally infected with H.nana eggs. Mice were sacrificed at different durations post infecion [p.i.]. Small intestine, liver and brain of each sacrificed mouse were removed. Couning of cysticercoids and adult worms in small intestine was performed. Livers were examined histopathologically for the possible cysticercoid disseminalion. Brains were processed for histopathological examination and immunohistochemical examinalion for the possible antigenic deposition by PAP technique. In addition the brain tissue was processed for biochemical estimation of the levels of some neurotransmitters as: Gamma-aminobutyric acid [GABA], norepinephfine [NE] and serotonin [5-HT] as well as zinc as one of trace elements. The results of the present study showed a significant increase in the number of cysicercoids and adult worms with delayed expulsion in immunosupressed [IS] mice with manifest histopathological changes in small intestinal mucosa. Aberrant cysticercoids were detected in the liver of IS mice. Regarding the brain examination, there were marked histopathological changes with specific antigenic deposition in IS mice. There were statistical increase in the levels of GABA and NE and staistical decrease in the levels of 5-HT and zinc in brains of IS mice examined at 3 and 5 months p.i. On the basis of the results of the present study, it has been shown that in case of immunosuppression, Hymenolepis nana infection can affect the brain as evidenced by the marked histopathological changes, specific antigenic deposition and the significant changes in the levels of neurotransmitters and zinc in the brain tissue. Since H. nana is widespread and since increasing numbers of patients are given immunosuppressive treatment, it is possible that this peculiar neurological manifestation of H.nana infection is occurring but not being diagnosed. The pathogenesis of such manifestations seemed to be dependent on multifactors that acting together and affecting each other