Figure 1

Histopathological characteristics of Onchocerca dewittei japonica in nodules excised from Cases 1 in Hiroshima (A–C) and 2 in Shimane (D–F). A) Mass (arrow, 1 × 3 cm) excised from the back of the right hand. B) Longitudinal section of the female O. dewittei japonica. Arrows, triangular transverse ridges; arrowhead, middle layer of the cuticle without the inner striae; white vertical line, cuticle; M, muscle layer. HE staining. C) Slightly oblique transverse section of the female worm showing the thick cuticle. Arrow, elevation of the cuticle, indicating the transverse ridge; asterisks, lateral chords; M, muscle layer. HE staining. D) Transverse section of the male O. dewittei japonica. I, intestine; M, muscle layer; SV, seminal vesicle with spermatozoids. HE staining. E) Enlarged transverse section. Arrows, small ridges on the cuticle; M, muscle layer; SV, seminal vesicle. HE staining. F) Slightly oblique transverse section. Arrows, small longitudinal ridges; M, muscle layer; SV, seminal vesicle. PAS staining. Unit of bars, μm.