EN
The gravid proglottids of Taenia saginata from human infection before and after treatment of patient with niclosamide (Yomesan) were used for studies on oncosphere envelope ultrastructure. The envelopes examined were intact after drug treatment. The samples from niclosamide-treated and untreated patients were similar with respect to number and kinds of the protective structures surrounding the oncospheres inside gravid proglottids. Their morphology was generally similar to this described earlier for other taeniid species. Details of the ultrastructure of oncospheral envelopes from niclosamide-treated patients are presented in the paper. Contamination of the environment with eggs from treated patients, particularly in poor sanitary conditions, is discussed.