Ultrastructural interactions of larval bird schistosome Trichobilharzia regenti and immune cells of hosts nervous system

Trichobilharzia regenti is a neurotropic fluke belonging to family Schistosomatidae. Larvae called schistosomula migrate in the definitive hosts (anseriform birds) throuth the central nervous system (CNS) to their final location in nasal mucosa, where they mature and lay eggs. In contrast with that, the infection of accidental mammalian hosts (including human), is often stopped already in the skin immediately after entering the host. However, some schistosomula are able to reach CNS of experimentally infected mice, and survive there temporarily. Reaction to the CNS infection of mice is usually provided by microglia, astrocytes or the other immune cells infiltrated from the hosts blood. Parasite protects itself against the host reaction with its tegument. It does not serve only as mechanical barrier, but also as main secretoric organ that is capable of active immune evasion. Changes within CNS of the vertebrate hosts, caused by migrating schistosomula of T. regenti, were already described by routine histological and immunohistochemical methods. Till now, there was a lack of informations about interactions of immune cells of the host and the tegument of the parasite on ultrastructural level. To fill this gap in knowledge, two different methods were used: (1) imunohistochemistry in light and electron..