A reliable assessment of the viability of schistosome eggs trapped in host tissues is difficult. The use of a coupling azo dye method for the detection of alkaline phosphatase (AlP) in Schistosoma mansoni ova was found to be a specific and sensitive method for differentiating between viable and dead eggs, and can be used in both immature and mature eggs. In fully developed miracidia within an egg, AlP activity was demonstrated in germ cells and in the sensory endings neural cells. The embryonating miracidia displayed AlP activity on the body surface and in von Lichtenberg's envelope. The alkaline phosphatase test for egg viability shows increased sensitivity when compared with the more conventional Oogram and Hatching tests.

Institute of Parasitology Academy of Sciences of the Czech Republic Ceské Budĕjovice

Schistosomiasis at the Crossroad to Elimination: Review of Eclipsed Research with Emphasis on the Post-Transmission Agenda