Current trends in tissue-affecting helminths.

Some helminths have by their evolution learnt to systemically invade a host organism, and to select specific organs or host cell types as predilection site to reside, maturate or even proliferate. These parasites needed to develop complex and unique strategies to escape host immune reactions. The present work sheds some light into the strategy developed by three different helminths (Echinococcus multilocularis, Trichinella spiralis and Toxocara conis) to survive in the host organ or host cell, respectively. The crucial role of periparasitic host reactions that may help the host to control the parasite, but which may also be responsible for immunopathological events harmful to the host himself, are elucidated as well. Finally, for these three parasites selected, the murine host appears an acceptable model for carrying out experimental studies, as for these parasites, rodents as well as humans become infected in the parasites natural life cycle. Therefore, conclusions drawn from murine experiments may provide much more reliable data in view of their relevance for the human infection, a fact that frequently lacks when using mice as experimental model for other helminths.