Morphological Studies of the Adult Female Loa loa (Nematoda：Filarioidea) and a Review of the Literature on Imported Human Loiasis in Japan

The morphological features of the adult female Loa loa worm obtained from the right eye of a Nigerian male and a review of the literature on five cases of imported human loiasis in Japan are described. The morphological characteristics of the main portions of the adult female worm were as follows：1) The worm body was threadlike, cylindrical in form and creamy-white in color, measuring about 5.0 cm in length and 0.6 mm in maximum diameter. 2) The body was widest at the base of the esophagus and tapered gradually to a lesser diameter posteriorly. 3) The body wall was approximately 108 μm thick, and numerous small bosses were recognized on the cuticular surface. 4) The cuticular bosses were round, wart-shaped structures that were about 20 μm in maximum diameter and 17.5 μm in height. 5) The bosses on the body surface began at a level posterior to the base of the esophagus and extended to the end of the tail. 6) The nerve ring was recognized about 0.2 mm from the cephalic end of the worm. 7) The esophagus was about 0.1 mm in length and 90 μm in maximum diameter, and the intestinal tube was about 200 μm in maximum diameter. 8) The vulva was situated posterior to the base of the esophagus in the ventral midline. 9) The uterine tube was about 170 μm in maximum diameter and contained numerous microfilariae. 10) The anal opening was located in the ventral region about 0.2 mm from the tip of the tail. Detailed morphological informations about the adult female Loa loa worm from human body in Japan are given in this paper for an original report.