Surface ultrastructure of larval Anisakidae (Nematoda: Ascaridoidea) and its identification by mensuration.

The surface ultrastructure of larval Anisakis type I, Anisakis type II, Raphidascaris, Contracaecum type A, Thynnascaris type A and Thynnascaris type B was examined by scanning electron microscopy. These species were identified clearly by the presence of a boring tooth, a mucron, and other morphological features. The means of the distances between transverse striations (DBTS) of larval Anisakis type I (5.45 +/- 0.125 micron), larval Raphidascaris (2.92 +/- 0.051 micron), and larval Contracaecum type A (1.68 +/- 0.056 micron) are significantly different (p less than 0.05). There was a correlation between the diameter of worm trunk (DOWT) and DBTS among these three larval types. In most cases a larva could be identified from the mean value of DBTS and DOWT even if obtained as a fragment from a patient.

[Ultrastructural changes of the tegument on Diphyllobothrium erinacei and Hymenolepis nana treated with paromomycin sulfate in vitro].

The effects of paromomycin sulfate on Diphyllobothrium erinacei and Hymenolepis nana in vitro were examined morphologically with a scanning and a transmission electron microscope. D. erinacei was incubated for 3 and 6 hours at 37 degrees C in a culture medium, 0.85% physiological saline solution, containing 0.5% paromomycin sulfate. H. nana was incubated in the same medium for 3 hours only. The concentration of paromomycin sulfate was set basing on the results which Kitamoto (1968) reported as the concentration level in feces after administrations of this drug in a clinical survey. The effect of the drug on the surface structure in both worms appeared markedly in the neck region. Mechanisms of breakdown on the tegument were supposed as follows. First, microtriches were disconnected from the tegumental surface and many vesicles were formed in the cytoplasm of the tegument. Finally, the tegument layer was excoriated to exposed the basal lamina. In 6 hours incubation, this surface of the worm suffered more damage than that in 3 hours. The damage of the basal lamina as in the case of D. latum expelled from a man by paromomycin (Y. Tongu et al.), however, could not be observed in the present study in vitro. It suggests that the destruction of basal lamina usually observed with the expelled worms from clinically treated human might be due to the combined effect of digestive enzymes secreted from host and the mechanical impact of intestinal peristalsis. Some of the vesicles in the tegument may originate from mitochondria because the fine structure of cristae were occasionally observed remaining in the vesicles.

[Ultrastructural changes in Diphyllobothrium latum from a man treated with paromomycin sulfate].

The effect of paromomycin sulfate on Diphyllobothrium latum in vivo in man was examined morphologically with a scanning and a transmission electron microscope. The worm used for this study was expelled from a man by treatment with paromomycin sulfate at 1 dose of 50 mg/kg. The surface of the neck region suffered great damage. The effect of paromomycin sulfate resulted in the progressive breakup of the microtriches and the tegument. Even the basal lamina was lost in some parts. As a result, the muscle layers were exposed directly to the air. In the immature proglottid, the basal lamina remained as an outermost surface, although paromomycin sulfate caused a great loss of the tegument. The mature proglottid was lacking microtriches in some parts. However, most of the tegument was covered with microtriches. The gravid proglottid remained without any loss of microtriches.