Cystic echinococcosis: aspects of immune response, immunopathogenesis and immune evasion from the human host

Cystic echinococcosis (CE) is a neglected infectious disease caused by the larval stage of Echinococcus granulosus. It constitutes a major public health problem in developing countries. During CE, the distinguishing feature of the host-parasite relationship is that chronic infection coexists with detectable humoral and cellular responses against the parasite. In order to establish successfully an infection, E. granulosus releases molecules that directly modulate the host immune responses favoring a strong anti-inflammatory response and perpetuating parasite survival in the host. In vitro and in vivo immunological approaches, together with molecular biology and immunoproteomic technologies provided us exciting insights into the mechanisms involved in the initiation of E. granulosus infection and the consequent induction and regulation of the immune response. Here, we review some of the recent developments and discuss how these observations helped to understand the immunology of E. granulosus infection in man. Although the last decade has clarified many aspects of host-relationship in human CE, establishing the full mechanisms that cause the disease require more studies. We need to define more clearly the events that manipulate the host immune response to protect the E. granulosus from elimination and minimizing severe pathology in the host.