Morphological observations and the effects of artificial digestive fluids on the survival of Diploscapter coronata from a Japanese patient.

Unusual non-human parasitic nematodes and eggs were detected in the faeces of an 8-year-old Japanese female suffering from Henoch-Schönlein purpura. The worms were adult female rhabditiform nematodes measuring 325.6-441.2 micro m in length and 18.3-26.5 micro m in width. One pair of the labia oris was notched with many spiny projections, while the other pair was strongly curved outwards. The worms were identified using light and scanning electron microscopy as the free-living nematode Diploscapter coronata (Cobb) based on their characteristic morphology. The patient's faeces containing worms and eggs were cultured using a filter-paper culture technique and after 7 days of culture, male as well as female worms were recovered. Worm survival time and hatchability of the eggs were examined in vitro after treatment with an artificial gastric or intestinal fluid. Although adult worms survived for less than one minute, eggs hatched after treatment with artificial gastric fluid. This suggests that eggs accidentally ingested or produced by adult D. coronata could develop in the human gastro-intestinal tract. Some morphological features of male D. coronata are also described.

Gnathostomiasis possibly caused by Gnathostoma malaysiae.

Gnathostomiasis is rarely reported in travelers, although the disease remains a major public health problem in Southeast Asia. A creeping eruption and Quincke's edema (slowly migrating erythema with pruritus) appeared in two Japanese men who had eaten raw freshwater shrimp in Myanmar. A Gnathostoma larva was found in subcutaneous tissue from one of the men. Four species causing human gnathostomiasis, G. hispidum, G. doloresi, G. nipponicum and G. spinigerum, can be distinguished based on the number of nuclei in intestinal epithelial cells of infected larvae, in cross-section. In G. hispidum, only a single large nucleus is found. Morphologically, our larva was initially identified as G. hispidum. However, since the number of epithelial cells was greater and the body width was larger than those of a "large-type" 3rd-stage larva of G. hispidum, the larva was then identified as a 3rd-stage larva of G. malaysiae, Miyazaki and Dun, 1965, as reported by Setasuban et al, (1991). Since no human cases caused by this species of Gnathostoma have previously been encountered, this appears to be the first report of gnathostomiasis due to G. malaysiae.

Arginine-dependent generation of reactive nitrogen intermediates is instrumental in the in vitro killing of protoscoleces of Echinococcus multilocularis by activated macrophages.

The interaction between protoscoleces of Echinococcus multilocularis and activated murine macrophages was examined in this study. Marked protoscolicidal activity was displayed by peritoneal macrophages (PM) activated with interferon-gamma (IFN-gamma), or IFN-gamma plus lipopolysaccharide. Pretreatment of the parasites with heat-inactivated specific murine infection serum, but not with normal serum rendered them more susceptible to PM killing. NG-monomethyl-L-arginine, a competitive inhibitor of L-arginine completely inhibited the killing activity of activated PM, while reconstitution of arginine-free medium with L-arginine restored the killing properties of the activated PM. The results show that activated PM have the ability to kill E. multilocularis protoscoleces in vitro and suggest that reactive nitrogen intermediates (RNI) play an important role in the mechanism. An oxygen-mediated mechanism did not appear to play a role because scavengers of reactive oxygen species did not reduce the killing activity. The arginine-dependent killing mechanism was enhanced by superoxide dismutase (SOD), probably because SOD might prolong the effect of nitric oxide. Secretion of RNI by activated macrophages may be capable of a significant role in preventing of the dissemination of E. multilocularis infection in vivo.

A case of spirurid larva infection in the anterior chamber of the human eye.

A 39-year-old male living in Yamanashi Prefecture, Japan, who complained of headaches, and redness, the sensation of foreign bodies and puffy eyelids of the left eye, visited the Department of Ophthalmology, Yamanashi Medical College. A larval nematode was found in the anterior chamber of the left eye and removed through a limbic incision. This nematode was identified as the spirurid type X larva.

Hepatocellular carcinoma associated with chronic Schistosoma mansoni infection in a chimpanzee.

Hepatocellular carcinoma associated with chronic Schistosoma mansoni infection in a chimpanzee, estimated to be a 12-year-old and born in West Africa, is reported. The hepatic tumor appeared as a solitary firm nodule, and histological examination revealed well-differentiated hepatocellular carcinoma with a trabecular pattern. Hepatitis B virus and hepatitis C virus infections were excluded by serological testing in that animal. This is the first report of hepatocellular carcinoma in the chimpanzee with schistosomiasis.

A case of ileus caused by a spiruroid nematode.

A 34-year-old male living in Aichi Prefecture, Japan, complained of lower abdominal pain. Ileus was suspected based on his clinical history and symptoms, and a laparotomy was performed. Four sections of a nematode were found in a large eosinophilic granuloma in the intestinal wall, and were identified as the larva of a spiruroid nematode. This is the third reported case of a spiruroid nematode infection found in the ileum.

A case of abdominal syndrome caused by the presence of a large number of Anisakis larvae.

A 58-year-old woman living in Shizuoka Prefecture, Japan, complained of severe epigastric pain and nausea about 8 h after having eaten 'Sashimi'. A gastrocamera examination undertaken as a result of her clinical history of gastric anisakiasis indicated that a large number of worms had penetrated the posterior walls. Fifty-six larval nematodes were directly removed from the greater curvature of the stomach with a gastroendoscopic biopsy clipper, and were identified as the larvae of Anisakis simplex.

Anisakidae larvae found in marine fishes and squids from the Gulf of Tongking, the East China Sea and the Yellow Sea.

Marine fishes and squids caught in the Gulf of Tongking, the East China Sea and the Yellow Sea were dissected, and many Anisakidae larvae were found in them. The larvae of Anisakis simplex (Anisakis Type I larvae), the most important causative agent of anisakiasis, was found in about 30% of fishes and squids caught in the Gulf of Tongking and in about 60% of those caught in the East China Sea and the Yellow Sea. Larvae belonging to three other genera than Anisakis--Raphidascaris or Raphidascaroides, Hysterothylacium, and Terranova (Cannon Type I)--were also detected.

Lethal efficacy of extract from Zingiber officinale (traditional Chinese medicine) or [6]-shogaol and [6]-gingerol in Anisakis larvae in vitro.

The authors previously reported that an extract from Zingiber officinale, traditionally eaten along with raw fish and used in traditional Chinese medicine, effectively destroyed Anisakis larvae in vitro. In this study, we analyzed the effective components of ginger rhizomes. Methanol extracts were fractionated after first being treated with HCl at pH 3, then with NaHCO3 at pH 10, and, finally, with NaOH at pH 13 (fraction 1). In general, this fraction is rich in neutral substances. [6]-Shogaol and [6]-gingerol, known neutral components of ginger rhizomes, were detected using gas chromatography and were found to be the most prevalent components in the fraction, occurring in quantities that resulted in a dose-dependent killing efficacy. Authentic [6]-shogaol and [6]-gingerol could kill Anisakis larvae at a minimal effective dose of 62.5 and 250 micrograms/ml, respectively. However, the concentration of [6]-gingerol in fraction 1 was greater than 20 times that of [6]-shogaol, making the former the most active component in the fraction. Furthermore, synergistic effects between [6]-gingerol and a small amount of [6]-shogaol were observed. Pyrantel pamoate, an available antinematodal drug, had no lethal effect, even at a concentration of 1 mg/ml. In saline solution containing [6]-shogaol (62.5 micrograms/ml), greater than 90% of larvae lost spontaneous movement within 4 h and were destroyed completely within 16 h. Microscopical examinations showed destruction of the digestive tract and disturbances of culticulae.

[Fifty-six cases of human dirofilariasis reported in Japan--a complied table].

Since the first reported case of human dirofilariasis in 1964, a total of 56 cases have been recorded from Japan, including 39 pulmonary and 16 extra-pulmonary cases. The difference in case number between pulmonary and extre-pulmonary sites is statistically highly significant (P = 0.001). Distribution of the lesion in pulmonary dirofilariasis is mainly concentrated in the right lung (P less than 0.001). The rapid increase of human dirofilariasis within the last 5 years indicates that this disease is one of the important anthropozoonoses.

Human cases of infection with canine whipworms, Trichuris vulpis (Froelich, 1789), in Japan.

The eggs of Trichuris, detected in the feces of 19 persons who had stayed in institutions for mentally retarded and/or multi-handicapped patients, were identified as those of T. vulpis (Froelich, 1789) on the basis of morphological features. This is the first record of human infection with the canine whipworm in Japan.

The value of external morphology in the identification of larval anisakid nematodes: a scanning electron microscope study.

We studied larval nematodes of four genera of the Anisakidae using a scanning electron microscope (SEM). The anterior and posterior extremities and cuticular structures of the 3rd-stage larvae (L3) of Anisakis type I, Pseudoterranova decipiens, Contracaecum type B and Hysterothylacium were examined. The 4th-stage larvae (L4) of Anisakis type I, P. decipiens, recovered after infection into laboratory rats, and the L3 and L4 of Anisakis type I larvae from human were also examined in the same way. There were generic differences in the shape and size of the lip bulges, external papillary structures, the appearance of the boring tooth, the width and depth of the grooves and ridges of the cuticle and the caudal structures of the L3. In Anisakis type I and P. decipiens L3, changes were seen in the anterior extremity, cuticle and posterior extremity after molting to the L4. Similar changes can be expected in larvae infecting man. The L4 of Anisakis type I from rat and man were similar, while the L4 of Anisakis type I and P. decipiens showed differences. These ultrastructural differences might be of value in the identification of fragments recovered during endoscopy in man.

A report of the first case of Dirofilaria infection in the eyelid region in Japan.

Dirofilaria worms were recovered from a painless hard tumor in the right eyelid of a 19-year-old Japanese male who had lived in Kagoshima and Kumamoto Prefectures, Japan. In the worms, the cuticle had a smooth surface, the inner cuticular layer had internal lateral longitudinal ridges, and the musculature of the body wall was the polymyarian type. On the basis of all morphological characteristics observed, this worm was identified as an immature female Dirofilaria immitis. This is the first human case of nematode infection in the eyelid in Japan. Surgical removal of the mass with worms resulted in complete recovery from swelling of his right eyelid.

[Therapeutic effect of paromomycin sulfate on the 13th case of Mesocestoides lineatus infection found in Japan].

Mesocestoides tapeworm is a common cestode in carnivorous mammals, but human infection with the tapeworm of this genus have been infrequent. We have recently observed the 13th case of human infection with Mesocestoides lineatus in Japan. A 35-year-old man living in Gifu prefecture was admitted to our University Hospital with chief complaints of general fatigue and discharge of cestode segments in his stool. The patient gave a history of drinking blood and eating the raw liver of a snake Agkistrodon halys for medicinal purposes as same as the previous cases of all reported in Japan. The segments were identified as those of M. lineatus. He was treated orally 3 g of paromomycin sulfate. Stool examination after treatment with paromomycin sulfate revealed no evidence of parasitism. The present case may be the 2nd to have been successfully treated with paramomycin sulfate and the 21st case of Mesocestoides tapeworm infection in man described in the literature.