Decalcification of schistosome eggs during staining of tissue sections: a potential source of diagnostic error.

Miracidial nuclei within calcified schistosome eggs are frequently mummified. Calcified eggs are often decalcified prior to or during the routine processing and staining of tissues, and mummified miracidial nuclei then stain clearly and are often arranged in the patterns seen in live eggs. These miracidia may be incorrectly assumed to be alive or to have died recently and thus be taken as evidence of an active infection requiring chemotherapy. The present observations demonstrate the decalcification of mineralized eggs by hematoxylin preparations used for routine staining of tissue sections.