Eggs as a Suitable Tool for Species Diagnosis of Causative Agents of Human Diphyllobothriosis (Cestoda)

Background: tapeworms of the order diphyllobothriidea are parasites of tetrapods and several species may infect man and cause neglected human disease called diphyllobothriosis. identification of human-infecting diphyllobothriid cestodes is difficult because of their morphological uniformity,which concerns also their eggs in stool samples. methods: in the present study,we analysed by far the largest dataset of more than 2,000 eggs of 8 species of diphyllobothriid cestodes that may infect humans,including the most frequent human parasites diphyllobothrium latum,d. nihonkaiense and adenocephalus pacificus (syn. diphyllobothrium pacificum). size (length,width and length/width ratio) and the surface of the egg shell from naturally and experimentally infected hosts were studied using light and scanning electron microscopy. results: a high degree of intraspecific and host-related size variability has been detected,but combination of morphometrical and ultrastructural data made it possible to distinguish all of the studied species,including otherwise quite similar eggs of the 3 most common species infecting man,i.e. d. latum,d. nihonkaiense and d. dendriticum. the surface of all marine species is covered by numerous deep pits with species-specific density,whereas the surface of freshwater species is smooth or with isolated shallow hollows or wrinkles. © 2016 leštinová et al.