The severity of mouse pathologies caused by the bird schistosome Trichobilharzia regenti in relation to host immune status.

Cercariae of the nasal bird schistosome Trichobilharzia regenti are able to penetrate into mammalian skin and migrate to the mouse central nervous system (CNS) causing tissue injury in certain cases. Our study shows that the severity of T. regenti pathologies in the CNS closely depends on the host immune status. During the primary infection of immunocompetent mice, the parasites evoked an acute inflammatory reaction in the skin and the CNS involving focal oedema and cellular infiltration of the tissue. Challenge infections resulted in the development of extensive inflammatory foci in the host skin which precluded the subsequent migration of the schistosomula to the CNS. On the other hand, during primary as well as challenge infections of immunodeficient mice (SCID), no significant immune response against the parasites was detected in any of the host organs examined; however, in contrast to immunocompetent mice, the infections were frequently manifested by severe leg paralysis. Copyright 2004 Springer-Verlag