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Strongyloides procyonis Little, 1966 was detected about 45 years ago in raccoons (Procyon lotor) of southern Louisiana, U.S.A., and was demonstrated experimentally to cause creeping eruption and a short-lived intestinal infection in a healthy human volunteer. After its description and demonstration of its pathogenicity in humans, S. procyonis has not been found in raccoons in North America despite repeated surveys. During a survey on feral raccoons in Japan, S. procyonis parasitic females were identified in 66 (28.3%) of 233 raccoons collected between May 2004 and January 2005. The number of parasitic females recovered from individual raccoons was 1-197 (geomean, 3.2). Both the morphological features and the nucleotide sequences of the small and large subunit ribosomal RNA genes (SSU/LSU rDNA) of S. procyonis closely resembled those of zoonotic Strongyloides stercoralis. The sequences of internal transcribed spacer (ITS)1 and 28S rDNA could differentiate clearly these 2 species. Awareness of S. procyonis in raccoons in North America and other places worldwide where raccoons are introduced and naturalized is important to assess the epidemiological significance of this potentially zoonotic helminth species.

Since skin is the only route of entry of the parasite in schistosomiasis patients, intervention at the level of skin penetration should control the infection. Several compounds were screened for their ability to protect against cercarial penetration. Hinokitiol (beta-thujaplicin) was found to have a significant cercaricidal effect in vitro, although there is no information on its cercaricidal mechanisms. To study the kinetics of morphological changes in Schistosoma mansoni associated with exposure to hinokitiol in vitro, cercariae were incubated in media containing hinokitiol at different concentrations and examined by transmission electron microscopy (TEM). TEM revealed that ultrastructural changes occurred by 15 minutes post exposure, at a concentration of 25 microg/ml. Degenerative changes involving both tegument and deeper parenchymal structures were progressive with duration of exposure at the concentration of 50 microg/ml. These structural changes may account for the inability of hinokitiol-treated cercariae to infect the host.

Larva migrans caused by the common raccoon ascarid, Baylisascaris procyonis, is a zoonotic disease of critical importance in North America. Recently we encountered the first proven outbreak of this disease in Japan in domestic rabbits (Oryctolagus cuniculus) in a small wildlife park. In this park, raccoons (Procyon lotor) had been kept for 9 years, and one raccoon was donated to the park by a pet owner 8 weeks prior to the occurrence of an outbreak in rabbits. Of 12 total raccoons, three raccoons including the donated one shed B. procyonis eggs in the feces, and two of these positive raccoons were kept in metal mesh cages on wooden pedestals, 2 m distant from the rabbit enclosure. Circumstantial evidence indicates that the donated raccoon is the likely source of this outbreak. Treatment of the raccoons with an ascaricide and decontamination by extensive flaming of the cages and the contaminated dirt floor of the park achieved a transient disappearance of ascarids from all 12 enclosed raccoons. Three months after the control measures began, recurrent ascarid infection was detected in three young raccoons of less than 1.5 years of age. The potential risk of serious zoonosis by B. procyonis as well as the difficulty in a clearance of contaminated areas should be considered by pet owners and public health workers in Japan.

A syndrome of progressive neurological signs was noticed in rabbits (Oryctolagus cuniculus) kept in a small wildlife park in mid-July 2000. Three out of 12 common raccoons (Procyon lotor) kept in this park were infected with Baylisascaris procyonis, and the larvae were found from affected rabbits. This outbreak is the first proven B. procyonis larva migrans in Japan, and the potential risk of serious zoonosis by this ascarid species should be considered by pet owners, veterinarians, physicians and public health authorities in this country as in North America where raccoons are endemic.

In the winter of 1998-1999, we collected parasitological data from 54 wild carnivores in the north-western part of Tohoku region, Japan. These consisted of 38 martens (Martes melampus melampus), 14 raccoon dogs (Nyctereutes procyonoides viverrinus) and 2 foxes (Vulpes vulpes japonica). Collected helminth parasites were 11 nematode, 10 trematode, 3 cestode, and a single acanthocephalan species, including 5 hitherto unknown species for this research area or the mainland of Japan (Honshu). Mesocestoides paucitesticulus was for the first time recorded from martens as well as from carnivores distributed in Honshu. Brachylaima tokudai originally recorded from Urotrichus talpoides in the central part of Honshu was for the first time found from a raccoon dog.

We compared temporal changes in the cell composition of the skin-draining lymph nodes (SLN) in guinea-pigs exposed percutaneously to normal or attenuated cercariae of Schistosoma mansoni. Different populations were analysed by flow cytometry of double-stained cells by monoclonal antibodies to the major histocompatibility complex class II molecule and lymph node cells of guinea-pigs. Exposure to S. mansoni caused a marked increase in the proportion of B cells and dendritic cells (DC) on day 2, reaching a peak number on day 4. These changes were comparable in both infected and vaccinated animals exposed to normal or attenuated parasites, respectively. Total number of DC, however, showed different kinetics; in infected animals, the number peaked on day 2 and then gradually declined, whereas it reached a higher peak on day 4 in vaccinated animal. Daily injection of bromo-deoxyuridine after exposure to the parasite reduced the total number of DC in the SLN on day 4. A reduction in DC counts in the contralateral side SLN was also evident in vaccinated animals. Our results indicate that a significant number of newly formed DC are recruited to the skin by 4th day of vaccination, followed by increased efflux to the SLN. It is possible that retention of attenuated S. mansoni in the skin may cause accelerated recruitment of newly formed DC from the bone marrow, and facilitate transport and processing of antigens highly expressed on attenuated parasites.

In the present study cohorts of ICR and BALB/c mice were immunized with u.v.-irradiated cercariae of S. mansoni and challenged 5 weeks later, in parallel with unimmunized control mice, with approximately 100 cercariae. Total worm burdens at 5, 6, 7 and 8 weeks after challenge were significantly reduced by 27–65% in immunized mice. The total number of eggs and the number of eggs/female worm trapped in liver and small intestine were reduced significantly at 6 and 7 weeks post challenge in immunized, as compared to unimmunized mice. Decrease in tissue egg load could be achieved in BALB/c mice passively transferred with spleen cells from u.v.-attenuated cercaria-immunized mice. The proportion of female worms laying eggs in vitro was diminished only in worms recovered from highly resistant mice. The reduction in worm oviposition in immunized mice was no longer apparent at 8 weeks. The data taken together indicate that highly effective immunization of outbred and inbred mice with attenuated cercariae leads to significant, but transient, impairment in challenge worm egg production.

The time course of intestinal infection of golden hamsters (Mesocricetus auratus) with Taenia crassiceps was monitored every 2 days up to day 26 postinfection (p.i.). The isolate used was originally obtained from Clethrionomys rutilus on St. Lawrence Island, Bering Sea (USA), and shows a high level of enteral establishment without parenteral infection. Following oral administration of various numbers (3, 15, 30, or 60) of metacestodes, proportional numbers of cestodes attached their scolices to the mucosa of the middle (one-third) segment of the small intestine. Except for animals given 3 metacestodes, dislocation of cestodes to the posterior parts of the intestine was noted on days 10-14 p.i. and began faster in animals that had received larger numbers of metacestodes. Concurrent with dislocation or elimination of cestodes, there existed distinct increases in intestinal eosinophil peroxidase and myeloperoxidase activities. The number of mast cells in the lamina propria peaked on day 16 p.i., and specific serum IgG began to increase within 1 week p.i. The level of all these changes was dose-dependent. In prednisolone-treated animals that received 60 metacestodes, dislocation of cestodes was not evident, and mucosal inflammatory changes were suppressed to a considerable extent. The findings of this study are discussed as a model for the study of canine taeniasis.

A female patient had been suffering from intermittent tinnitus for several days. An otomicroscopic examination revealed a small mite moving on the tympanic membrane. The tinnitus increased when the mite was moving around the pars tensa and disappeared when the mite was moving on the surface of the external ear canal. After removal of the mite, the tinnitus disappeared.The mite was identified as Otodectes cynotis, which causes ear mange in dogs and cats. The patient had kept a dog and a cat inside her house for one year as pets. Examination of their ears revealed many Otodectes cynotis in the external ear canals. It was assumed that the patient was infected with Otodectes cynotis from those animals. As far as we know, this is the first case to be reported of a mite on the tympanic membrane. It is important to be concerned about parasite infestation from pet animals.

All trypanosome species classified in the subgenus Herpetosoma in sciurid hosts have been recorded from ground and tree squirrels to date, but not from any flying squirrels. We describe in this paper a novel trypanosome species, Trypanosoma (Herpetosoma) kuseli sp. n., from Siberian flying squirrels (Pteromys volans) imported from China, and compare it with T. (H.) otospermophili in Richardson's ground squirrels (Spermophilus richardsonii) and Columbian ground squirrels (Spermophilus columbianus) from the USA. Due to a short free flagellum, the new species appeared stumpy compared with T. otospermophili (length of free flagellum 7.0 +/- 0.8 microm, total length 32.1 +/- 0.8 microm, n = 13 and length of free flagellum 15.5 +/- 1.6 microm, total length 35.9 +/- 1.0 microm, n = 13, respectively). Another conspicuous morphological feature of the new species was an anteriorly positioned kinetoplast, found approximately at the midpoint between the nucleus and the posterior end. These characters have not been recorded from any squirrel Herpetosoma trypanosome species. Comparison of the nucleotide sequences of the small and large subunit rRNA genes indicated that T. kuseli sp. n. was more homologous to T. otospermophili than murid Herpetosoma species, such as T. grosi, T. lewisi, T. musculi, T. microti and T. evotomys.

Acanthocephalan everted cystacanths were detected in the intestines of 61 out of 555 feral raccoons (Procyon lotor) trapped between May 2003 and April 2005 in the western region of mainland Japan (Honshu). All collected specimens were identified as the species of birds including 3 Centrorhynchus species (C. bazaleticus, C. elongatus, and C. teres), Sphaerirostris lanceoides, Plagiorhynchus ogatai, Porrorchis oti, and Southwelina hispida. Three species, C. bazaleticus, C. teres, and S. lanceoides, were new to distribution records in Japan and the Far East. Recovery rates of these acanthocephalans were higher from the raccoons trapped in spring and early summer (range 8.3-36.8%, average 21.5%) than during the remainder of the year (range 0-20.0%, average 6.3%). The reason for this seasonal change is unknown. There is little information on the acanthocephalan fauna of wild birds in Japan, however, recovery of the cystacanths from the feral raccoons captured through the year might provide useful information on the fauna and geographical distribution of avian acanthocephalans.

Twin, white-fronted marmosets (Callithrix geoffroyi) born and raised in a zoo in Japan died at 7 mo of age. Several encapsulated nematode larvae were detected in the intestinal wall, as well as a few in the mesenteric lymph nodes of 1 of the twins. In the other marmoset, no encapsulated nematode larva was detected in the organs, but many adult Pterygodermatites nycticebi were found in the intestinal lumen. In the past 5 yr, 5 primates kept in the same zoo, i.e., 1 squirrel monkey (Saimiri sciureus), 2 Pygmy marmosets (Cebuella pygmaea), 1 Senegal galago (Galago senegalensis), and 1 cotton-top tamarin (Saguinus oedipus), died from heavy infestation with the same nematode. A few migrating larvae of the rictulariid were also identified histologically in the intestinal wall and liver of the cotton-top tamarin. Although no other primate currently held in the same zoo was infected with the rictulariid, German cockroaches (Blattella germanica) collected with traps near marmoset cages had encapsulated P. nycticebi larvae, indicating latent perpetuation of the life cycle of this rictulariid species in the zoo premises. Our results indicated that encapsulation or migration of third-stage larvae of P. nycticebi might occur accidentally in the organs of callithrichid primates.

application/pdf, Larvae of the raccoon roundworm, Baylisascaris procyonis (B. procyonis) are a known cause of cerebrospinal larva migrans in animals and humans. The present paper described details of the central nervous lesion in the rabbits (Oryctolagus cuniculus) affected with B. procyonis larva migrans in Japan. Clinically affected animals showed neurological signs including circling, torticollis, tremor of head, or ataxic gait. The most characteristic pathological alterations were large malacic lesions associated with an activated astroglial proliferation which was seen at the corpus medullare in the cerebellum including the cerebellar peduncle. Moreover, focal malacic lesions with perivascular cuffing and infiltration by lymphocytes and heterophiles were scattered everywhere throughout the brain. In these lesions or normal-appearing areas away from obvious lesions, ascarid larvae, about a maximum 65-75 μm in diameter, were recognized. Other prominent features were minute lesions (we call them migration tract-like lesions) composed of lymphocytes, hemosiderin-laden macrophages and reactive astrocytes scattering throughout the cerebrum. In this study, we demonstrated ascarid larvae in only eight out of 23 animals diagnosed as B. procyonis larva migrans. Since it is not always possible to detect the larvae, the possibility of B. procyonis larva migrans must be given serious consideration to the characteristic lesions described above.

Several studies have confirmed that epidermal Langerhans' cells (LC) play a central role in the induction of skin-related immunological events. In order to assess the role of LC in Chagas' disease, guinea-pigs were infected intradermally with Trypanosoma cruzi, sacrificed at different time-points, and their tissues were processed for routine histology, electron microscopy and immunohistochemistry. Parasitaemia was observed earliest at day 6 p.i. with 2 peaks at days 9 and 28, and disappeared on day 56 p.i. Parasite-specific serum IgG and IgM were first detected on day 12 p.i. The level of IgG gradually increased by day 84 p.i. All the infected guinea-pigs showed significant alterations in the distribution and morphology of epidermal LC during parasitaemia. The number of LC had significantly decreased in the epidermis by day 3 p.i., only returning to normal levels by day 56 p.i., although the number of LC in the underlying dermis increased concomitantly. Parasites were carried to the regional lymph node, where clustering of parasite-laden dendritic cells (DC) with lymphocytes was seen by electron microscopy. This evidence suggests that LC might be involved in antigen presentation in Chagas' disease.

In an epidemiological survey for Echinococcus multilocularis in rodents and insectivores from the northernmost part of the central mainland of Japan (Honshu), two taeniid species, Taenia crassiceps and Taenia polyacantha, were found in Microtus montebelli and Apodemus argenteus, respectively. The latter is the first record of distribution in Japan, and the former is the second after its first recovery from the central part of Japan. Although we have found neither larval nor strobilar stage of E. multilocularis there, discovery of these taeniid species, having overlapping global distribution with E. multilocularis in red foxes Vulpes vulpes as well as multiple occurrences of hydatid patients having no history of visits to the endemic areas shows the possibility that the life-cycle of E. multilocularis might be maintained at least in the northernmost part of Honshu.

Using histochemical ATPase-staining of the guinea pig epidermal sheet, we have demonstrated remarkable accumulations of ATPase-positive cells after exposure to attenuated Schistosoma mansoni cercariae. To characterize further the cells accumulating in the skin after exposure to S. mansoni, we produced a panel of monoclonal antibodies (MAb) to guinea pig leukocytes. These were immunohistochemically classified into 15 types and included MAb to the major histocompatibility complex (MHC) Class I and Class II molecules, shared antigens of all lymph node cells or between lymph node cells and Langerhans' cells (LC), T cells and macrophages (M phi), and M phi including the large Tingible body M phi in the secondary follicle. Varied MAb to M phi, including commercially available MAb (MR-1), were negative with ATPase- and MHC Class II-positive cells accumulated in the skin exposed to S. mansoni. Three MAb (HUSM-30 and 46, and commercially available MSgp2) detected an identical staining profile of accumulated cells with epidermal LC, but two MAb (HUSM-12 and 42) positively stained accumulated cells but not resident LC. These results indicate that the cells accumulated in the guinea pig skin within a few days after exposure to attenuated cercariae of S. mansoni are closest to LC, not to Mø, and may be blood-borne LC/dendritic cells.

In an attempt to determine whether in vitro oviposition of adult S. mansoni reflects the fecundity status of worms in vivo, Mongolian gerbils and ICR, BALB/c and SCID mice were infected with about 100 cercariae and examined on an individual basis, 5-12 weeks later, for worm burden, counts of eggs in liver and small intestine, and for the rate of egg deposition of ex-vivo female worms cultured in vitro, singly or in pairs, over a 3-5 day incubation period. The percentage of egg-laying female worms and the number of eggs laid/female after 3 days in culture showed, like worm fecundity in vivo, wide inter-worm variability, especially in 5-, 6- and 12-week-old worms; varied significantly with the age of the parasite with a maximum level attained by worms of approximately 8 weeks of age; and differed in worms recovered from different host species and strains. The data taken together indicate that measuring the egg-producing ability of S. mansoni in vitro reflects the fecundity status of worms in vivo and additionally provides likely explanations for hitherto poorly understood findings on schistosome fecundity.

Among soil-transmitted parasitic diseases, alveolar hydatidosis due to the ingestion of Echinococcus multilocularis eggs is becoming a serious problem in Hokkaido, the northern most island of Japan. Dissemination of the infection far from the endemic areas can occur if motor vehicles transmit soil contaminated with eggs. No appropriate and validated method for recovering the taeniid eggs from soil is available. A modified sugar centrifugal flotation technique, using a sucrose solution of specific gravity 1.27 and 0.05% Tween-80, was evaluated as a method to successfully recover eggs from soil. Contamination levels as low as 10 eggs per gram could be detected. This method may be useful to determine the prevalence of E. multilocularis, its transmission, and the potential for by monitoring soil contamination with eggs.

Schistosoma mansoni cercariae attenuated with ultraviolet (UV) irradiation (254 nm) at a dose of 18 mJ/cm2 induced partial resistance against a homologous challenge in male ICR mice and male Hartley guinea pigs. The reduction in the adult worm burden was 51% and 37% +/- 13%, respectively. On the other hand, male and female Mongolian gerbils (Meriones unguiculatus) vaccinated with UV-attenuated cercariae exhibited marginal resistance (13% +/- 9% and 22% +/- 10%, respectively). This raises the possibility that gerbils might have an unknown immune-characteristic nature. The usefulness of UV-attenuated cercariae is discussed with respect to the control of the disease.

Intermediate filaments (IFs) make up the cytoskeleton of most eukaryotic cells. In vertebrates, a number of IF proteins have been identified, showing distributions unique to tissue or cell type. Information on helminth IFs is limited to some nematode species. To observe immunofluorescent localization of IFs in helminth tissues, we selected a murine hybridoma clone producing IgM antibody to multiple types of mammalian IF proteins and examined cross-reactivity to helminth proteins. The selected monoclonal antibody (HUSM-9) cross-reacted well with IFs from nematode species such as Toxocara canis, Dirofilaria immitis, Anisakis simplex, and Trichinella britovi; strong immunofluorescence on cryostat sections was detected in the hypodermis, cords, body muscle, smooth muscle of the uterus, and other epithelial structures. In platyhelminths, i.e., adult Schistosoma mansoni, larval Taenia taeniaeformis, adult Taenia crassiceps, and Echinococcus multilocularis protoscolex, the reactivity was weaker than in nematodes, and localized in the body wall muscle and subtegumental tissue. Western blotting of 8 M urea extracts of parasites with the antibody detected a pair of clear bands in nematodes but not in S. mansoni or the cestodes. These results might be explained by sparse distribution of IFs in platyhelminths, or low affinity of the used antibody to platyhelminth IF proteins, or both.

The immunoglobulin E (IgE) response, a hallmark of helminthic infection, is generally considered a major host defense against schistosomiasis mansoni. In support, it was reported that mice with a null mutation of the Ce gene, which are thus incapable of making IgE, developed Schistosoma mansoni worm burdens 2-fold greater than wild-type mice. However, in another study, reduction of the IgE response in mice to a primary S. mansoni infection by anti-IgE treatment resulted in decreased worm burden and fecundity, suggesting that IgE plays a detrimental, rather than beneficial, role for the host in schistosomiasis. In a third study, S. mansoni worm burden and egg production in normal and in IL-4-deficient mice that produce negligible IgE levels did not differ significantly, and it appeared that IgE did not affect parasite survival or fecundity. In an attempt to resolve these controversies, we examined hepatic worm load and egg production in the liver and small intestine of IgE-deficient (SJA/9) and control IgE-producing (SJL/J) mice, 8 wk after S. mansoni infection. No differences were observed in worm burden, total egg production, and number of eggs produced per female worm in the 2 mouse strains, confirming the data that imply that IgE does not play an essential role in primary S. mansoni infection.

Homologous challenge parasite attrition in gerbils, Meriones unguiculatus, chronically infected with Schistosoma mansoni, was investigated by the recovery technique of retrograde portal perfusion. Whereas the animals vaccinated with gamma- or UV-attenuated cercariae of S. mansoni showed a marginal level of resistance, the chronically infected gerbils exhibited significant parasite attrition against a homologous challenge infection. Our data do not corroborate a previous report suggesting a lack of resistance in gerbils with chronic S. mansoni infection. The gerbil represents an additional experimental host for evaluating acquired resistance to S. mansoni, including that induced by previous exposure to irradiated larvae on chronic infection.

Cystic hydatidosis (CH) caused by Echinococcus granulosus is an important zoonosis worldwide. Several serodiagnostic and ultrasound tests are currently used for screening asymptomatic CH. The sensitivity of the serodiagnostic tests has been demonstrated by several groups to be lower than ultrasonography (US). To explain the mechanism of the difference in sensitivity, a large-scale US survey combined with an IgG4-enzyme-linked immunosorbent assay test was conducted in Uruguay. Our results suggest that certain cyst images, e.g., multivesicular cysts, may be closely associated with a high antibody response regardless of the cyst size, whereas other hydatid lesions, e.g., solid images with/without rolled parasite membranes, have lower antibody responses with a close relationship to cyst size. Seropositivity of subjects who had been treated surgically for removal of hydatid cysts in the last 5 yr was closest to that of actual CH patients, albeit free from CH by US. These findings are important for the proper use of serodiagnostic tests and US for community-based epidemiological studies.

Five confirmed human cases of gnathostomiasis nipponica exhibiting creeping eruption and itching were found sporadically from the autumn of 1991 to the winter of 1992 in the northern region of the mainland of Japan. In all cases, a causative gnathostome with 3 transverse rows of hooklets on the head bulb was detected in biopsied skin. The morphological characteristics agreed with the advanced third-stage larvae of Gnathostoma nipponicum. Within a few weeks before development of symptoms, all patients had histories of eating raw freshwater fishes, kokanee (Salmo nerka nerka), carp (Cyprinus carpio), crucian carp (Carassius gibelio langsdorfi), or common ice-fish (Salangichthys microdon). However, they had never eaten raw loach, which is known as a source of human infections with G. nipponicum.

Utilisation d'œufs de S. japonicum fixes au formol pour le test de precipitation circum-ova dans la bilharziose

Compressed tissue autoradiography using [ 75 Se]selenomethionine labelled parasites has been used to investigate the migration potential of normal and radiation attenuated cercariae of Schistosoma mansoni in naive guinea pigs. By Day 14 after infection, 44% of normal parasites were detected as reduced silver foci in the liver; this value corresponded well with the number of liver parasites recovered by retrograde perfusion of the hepatic portal system on Day 42 (42% of the challenge). In contrast, cercariae subjected to 50 krad of gamma irradiation failed to migrate out of the skin. The migration capacity of 20 krad irradiated parasites was less severely affected in that about half of the challenge parasites reached the lungs, but virtually none moved to the liver. These data are discussed in relation to the kinetics of immunity induced in guinea pigs by infection or vaccination with normal or radiation attenuated parasites.

Dirofilaria immitis (Leidy, 1856) is widely distributed throughout the world and has a wide range of hosts including carnivores, ungulates, primates, etc. Human dirofilariasis has been reported, e.g., Beaver and Orihel (1965, Am. J. Trop. Med. Hyg. 14: 1010-1029). In human cases, most of the lesions were observed in lungs and subcutaneous tissue. We detected a lung nodule, similar to human pulmonary dirofilariasis, in a female 7-month-old laboratory rabbit. The animal was one of 172 rabbits used in a nonrelated toxicological study. The nodule was detected just beneath the dorsal surface of the right cranial lobe of the lung. It was sharply circumscribed from surrounding tissue. Neither necrotic nor hemorrhagic change was observed in any other part of the lung. Lung tissue, including the lesion, was fixed in 10% neutral formalin and embedded in paraffin. Sections were stained with hematoxylin-eosin and Heidenhain's azocarmine (Azan). A piece of formalin-fixed lung lesion was dissected carefully using stereoscopic microscopy and a fragment of worm was collected and treated with lactophenol solution. Although serum of this rabbit was examined immunologically by the Ouchterlony technique using crude D. immitis antigens, no pr cipitation was observed. Microscopically, the nodule was an organized embolus surrounding the worm in a pulmonary artery (Fig. 1). Several sections of parasite were surrounded by an organized

A rare instance of human infection with an acanthocephalan is reported. A species of Bolbosoma, class Palaeacanthocephala, was found at laparotomy in a 51-yr-old Japanese fisherman who complained of acute abdominal pain. The parasite probably was acquired by eating raw fish (sashimi), perhaps bluefin tuna. Infections of humans with Acanthocephala are rare. Most of the reported infections have been with Moniliformis and Macracanthorhynchus (class Archiacanthocephala). Only a few reports of infection of humans by other classes are avail- able (Golvan, 1969; Schmidt, 1971). This paper reports the finding of an acanthocephalan para- site, Bolbosoma sp., in a Japanese man admitted to a hospital for acute abdominal pain. CASE REPORT

The release of Schistosoma japonicum cercariae from Leytean Oncomelania quadrasi snails was observed under laboratory conditions. Two patterns of emergence were noted. The initial, nonperiodic emergence occurred immediately after submerging the snails in water and was followed by a periodic, diurnal emergence which peaked in the afternoon. The daily cercarial output of the periodic emergence appeared to be affected by exogenous light intensity. Furthermore, there was a cessation or reduction in cercarial output every 3rd or 4th day.