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Human gnathostomiasis is a harmful foodborne parasitic infection caused by nematodes of the genus Gnathostoma. Here, we report an unusual case of gastric gnathostomiasis seen in a hospital in Thailand along with the clinical characteristics, treatment, and outcome. A 39-year-old man presented with complaints of epigastric pain, dizziness, and history of passing dark, tarry stools for 2 days. The patient had a history of consuming raw freshwater fish. Supplementary differential diagnosis was performed via rapid serological testing, and presence of the causative agent was confirmed based on video gastroscopy, morphology of the removed parasite, and molecular identification. After its surgical removal from the stomach, the parasite was morphologically identified as Gnathostoma species. Molecular identification was performed via DNA extraction from the recovered worm, and amplification and sequencing of the second internal transcribed spacer (ITS2) region and partial cytochrome c oxidase subunit I (cox1) gene. The ITS2 and cox1 sequences were consistent with those of Gnathostoma spinigerum. Clinicians in endemic areas should therefore be aware of the rare clinical manifestations and use of supplementary serological tests to facilitate early diagnosis and treatment of gastric gnathostomiasis.

Chinese edible frogs, Hoplobatrachus rugulosus, were examined to estimate the potential risks of human gnathostomiasis and sparganosis in Myanmar. A total of 20 frogs were purchased in a local market of Yangon and examined with naked eyes and the artificial digestion method after skin peeling in June 2018 and June 2019. Larvae of gnathostomes and Spirometra (=spargana) were detected in 15 (75.0%) and 15 (75.0%) frogs with average intensities of 10.5 and 6.3 larvae per infected frog, respectively. Gnathostome larvae were 2.75-3.80 (av. 3.30) mm long and 0.29-0.36 (0.33) mm wide. They had a characteristic head bulb with 4 rows of hooklets, a muscular long esophagus, and 2 pairs of cervical sac. The mean number of hooklets were 41, 44, 47, and 50 on the 1st, 2nd, 3rd, and 4th row, respectively. Collected spargana were actively moving, particularly with the scolex part, and have ivory-white color and variable in size. Conclusively, it has been first confirmed that Chinese edible frogs, H. rugulosus, are highly infected with larval gnathostomes and spargana in this study. Consuming these frogs is considered a potential risk of human gnathostomiasis and sparganosis in Myanmar.

Gnathostomes are of interest because of their unique appearance and medical importance. Among 13 valid species of the genus Gnathostoma Owen, 1836 (Nematoda: Spirurida), two species, G. doloresi Tubangui, 1925 and G. hispidum Fedtschenko, 1872, are parasites of pigs but their larvae can infect humans to cause gnathostomiasis. In this study, we collected adults of Gnathostoma sp. from the stomach of domestic pigs (Sus scrofa domesticus Linnaeus) from Dien Bien Province, northern Vietnam. Morphologically, nematodes found here are most similar to G. doloresi with a slight difference in the spicules of males. In contrast, they are genetically distinct from G. doloresi and other species of Gnathostoma in both ITS2 and cox1 sequences. The findings of the present study suggest that specimens of Gnathostoma sp. found in Dien Bien are likely a new species and emphasise the need of further studies on the taxonomy and phylogenetic relationship of species of Gnathostoma. Special attention should also be paid to swine and human gnathostomiasis in Dien Bien Province, Vietnam and the neighbouring areas of China and Laos.

Gnathostomiasis is a zoonotic parasitosis endemic in many Asian and some Latin American countries. Most human infections are caused by Gnathostoma spinigerum in Asia and Gnathostoma binucleatum in the Americas, and recently, imported cases have been increasing among travelers returning from endemic regions. Confirmation of the clinical diagnosis relies largely on serologic tests, with a G. spinigerum-antigen-based immunoblot currently being the diagnostic method of choice. However, we repeatedly experienced that sera from patients with clinically suspected American gnathostomiasis gave negative results in this assay. Therefore, we used homologous methods to prepare G. spinigerum- and G. binucleatum-antigen-based immunoblot assays, and evaluated the cross-reactivity of the two assays. The results show incomplete cross-reactivity between the two assays: the G. spinigerum-antigen-based immunoblot apparently only detects Asian gnathostomiasis caused by G. spinigerum, whereas the G. binucleatum-antigen-based immunoblot is apparently capable of detecting American as well as Asian gnathostomiasis., (© The American Society of Tropical Medicine and Hygiene.)

The present study was performed to determine the infection status of swamp eels with Gnathostoma sp. larvae in Myanmar. We purchased total 37 Asian swamp eels, Monopterus albus, from a local market in Yangon in June and December 2013 and 2014. All collected eels were transferred with ice to our laboratory and each of them was examined by the artificial digestion technique. A total of 401 larval gnathostomes (1-96 larvae/eel) were detected in 33 (89.2%) swamp eels. Most of the larvae (n=383; 95.5%) were found in the muscle. The remaining 18 larvae were detected in the viscera. The advanced third-stage larvae (AdL3) were 2.3-4.4 mm long and 0.25-0.425 mm wide. The characteristic head bulb (0.093 × 0.221 mm in average size) with 4 rows of hooklets, muscular long esophagus (1.025 mm), and 2 pairs of cervical sacs (0.574 mm) were observed by light microscopy. The average number of hooklets in the 1st, 2nd, 3rd, and 4th rows was 41, 45, 48, and 51, respectively. As scanning electron microscopic findings, the characteristic 4-5 rows of hooklets on the head bulb, a cervical papilla, tegumental spines regularly arranged in the transverse striations, and an anus were well observed. Based on these morphological characters, they were identified as the AdL3 of Gnathostoma spinigerum. By the present study, it has been confirmed for the first time that Asian swamp eels, M. albus, from Yangon, Myanmar are heavily infected with G. spinigerum larvae.

Adult gnathostomes were discovered in the stomach of the Jeju weasel, Mustela sibilica quelpartis, road-killed in Jeju-do (Province). Their morphological characters were examined to identify the species. Total 50 gnathostome adults were collected from 6 out of 10 weasels examined. In infected weasels, 4-6 worms were grouped and embedded in each granulomatous gastric tumor, except 1 weasel. Male worms were 25.0×1.4 mm in average size, and had a tail with pedunculate papillae, a spicule, and minute tegumental spines. Females were 40.0×2.5 mm in average size, and had a tail without tegumental spines. Pointed and posteriorly curved hooklets were arranged in 8-10 rows on the head bulb. Tegumental spines were distributed from behind the head bulb to the middle portion of the body. The spines were different in size and shape by the distribution level of the body surface. Fertilized eggs were 65.5×38.9 µm in average size, and had a mucoid plug at 1 pole. These gnathostomes from Jeju weasels were identified as Gnathostoma nipponicum Yamaguti, 1941. By the present study, it was confirmed for the first time that G. nipponicum is distributed in Jeju-do, the Republic of Korea, and the Jeju weasel, M. sibilica quelpartis, plays a crucial role for its definitive host.

The egg and larval stages of Gnathostoma turgidum were examined using light microscopy. Fertilized uterine eggs are 65.97 long and 32.28 wide, oval, brownish, with two cap-like thickenings. The eggshell surface is covered with numerous irregularly shaped pits of various sizes and depths. A sheathed second-stage larva emerges from the egg, measures 178 x 9; the sheath measures 243 x 21. Development to early third-stage larva in the coelomic cavity of cyclopoid copepods is similar to that described for other gnathostome species. After 10 days at 27 degrees C, the larvae undergo a molt (the second for gnathostomes) and develop to early third stage. The body of this stage measures 412.3 x 40.1, with evident hemispherical cephalic bulbs. Cephalic bulbs measure 25 x 40, armed with four transverse rows of sharp hooklets. The average number of hooklets in each row is 31, 34, 37, and 42, respectively. The whole body is covered with 193 transverse rows of small single-pointed cuticular spines. One pair of cervical papillae and an excretory pore are present on the anterior part of the body. On the other hand, potential species-specific features regarding the latter larval stage are discussed. Finally, some G. turgidum life cycle considerations are portrayed.

Two female advanced third-stage larvae of Gnathostoma turgidum recovered from the liver of one naturally infected four-eyed opossum Philander opossum pallidus collected in Oaxaca, Mexico, were morphologically examined. Because of some characteristics, the larvae do not fit into the typical advanced third-stage. The body shows a size at least three times larger than expected and rows of spines only in the anterior part of the body surface. Consequently, in this research, we document for the first time the precocity in third-stage larvae of G. turgidum, and we also highlight some facts about the fourth larval stage occurring in spirurins.

Morphological abnormalities were observed on the cephalic bulb hooklets of advanced third-stage larvae (AdvL(3)) of genus Gnathostoma. The larvae were obtained from the fish "Mexican rivulus" Millerichthys robustus collected from a seasonal pond near Tlacotalpan, Veracruz, Mexico. The abnormalities involved (1) extra rudimentary hooklets, located between the four rows and after the fourth row, (2) branched or lobulated hooklets, and (3) fragmented hooklets not uniformly disposed in rows. The alterations observed on the cephalic bulb hooklets do not represent intraspecific variations, and they may be considered as a potential tool for assessing the presence of pollutants or stressors located within the ecosystem.

Gnathostoma turgidum is a nematode that parasitizes the stomach of opossums, Didelphis virginiana. Despite its wide distribution in the Americas, its natural life cycle is poorly understood. Recently, we found an endemic area for G. turgidum infection in Sinaloa, Mexico (Diaz-Camacho et al., 2009). Based on sporadic surveys for several years, the prevalence was apparently high in summer and extremely low in winter. To confirm that this is really a seasonal variance, we conducted a longitudinal survey on G. turgidum infection in opossums from November 2007 to November 2008. The results showed amazing seasonal changes in the prevalence, with synchronized migration and maturation of worms in opossums. Between February and March, many juvenile worms, with occasional AL3, were found in the liver, but no worms were found in the stomach. Mature adult worms began to appear in the stomach around April and rapidly increased in number toward July, when all worms resided in the stomach. Then, the worms disappeared almost completely by November. These results suggest that G. turgidum is an annual parasite of the opossum, D. virginiana, in Mexico.

In order to clarify the role of Gnathostoma turgidum as an etiological agent involved in human gnathostomiasis in Mexico, establish the taxonomic identity of the advanced third-stage larvae (AdvL(3)), and contribute to the knowledge of its life cycle, experimental host infections, examination of potential natural hosts, and morphological comparisons were carried out. Examination of ten species of potential hosts at San Pedro las Playas and Tres Palos Lagoon in Guerrero state, Mexico revealed that two (Kinosternon integrum and Rana zweifeli) were infected by 15 AdvL(3) of G. turgidum. A specific identity was obtained comparing these larvae with those recovered from hosts experimentally infected. The AdvL(3) measured 1.6 mm in length, with two cervical papillae (both in 12th row) and an excretory pore on the 19th row. The average of cephalic hooklets, from first to fourth row, was 30.8, 34.0, 36.7, and 39.6, respectively. This is the first record of AdvL(3) of G. turgidum in America, and it represents a significant contribution for the understanding of the life cycle of this species.

Six specimens of freshwater stingrays from the French Guiana belonging to the genus Potamotrygon [S.W. Garman, On the pelvis and external sexual organs of selachians, with special reference to the new genera Potamotrygon and Disceus, Proc. Bost. Soc. nat. Hist. 19 (1877) 197-215], do not present characters that are typically shown by species to which they have been attributed. Five belong to a new species here named Potamotrygon marinae n. sp. This species is differentiated from the others by the feebly development of the prepelvic process, the development of the postorbital process as an enlarged blade, the unsegmented angular cartilage, the dorsal surface coloration composed of wide circular patches themselves formed by smaller pale patches, the almost dark coloration of the ventral surface tessellated with pale patches, and the small sized spiny tubercles situated in the middorsal region, before the caudal sting.

Advanced third-stage larvae of Gnathostoma sp. corresponding to 6 morphotypes, distinguished on the basis of the shape of the cephalic hooklets, were collected from the muscle tissue of 5 species of freshwater fish (i.e., Dormitator latifrons, Eleotris picta, Gobiomorus maculatus, Ariopsis guatemalensis, and Cichlasoma trimaculatum) in Tres Palos Lagoon, Guerrero, Mexico. Principal components analysis of 4 morphological characters cluster all samples in a single taxonomic group. A minimum amount of variation was observed among ITS2 sequences of 3 morphotypes and Gnathostoma binucleatum obtained from GenBank (0-0.84%). The observed variation among morphotypes 1, 2, and 3 is the result of intraspecific variability of G. binucleatum supported by morphology and DNA. Morphotypes 4, 5, and 6 belong to the same taxon on the basis of morphology of the hooklets only. For an accurate morphological diagnosis of the causative agent of gnathostomiasis, it is necessary to develop similar studies with other species of the genus.

Expansion in international travel and increases in immigration have resulted in an increased number of persons in Europe and other Western countries who have returned from foreign travel with parasitic infections rarely seen previously in the United States. Among the diseases caused by helminthic parasites is gnathostomiasis, a disease caused by Gnathostoma spp. Once confined primarily to Southeast Asia, it now is a public health concern in Mexico and other countries. This article reviews the causes and epidemiology of gnathostomiasis, the life cycle of the helminth, the clinical picture and diagnosis of gnathostomiasis, and the treatments for and means of avoiding the disease.

An analysis with SEM of the mouth parts of 16 species belonging to 10 genera of Gnathostomulida resulted in the following new characters and conclusions: 1) At least in the genus Haplognathia, jaw teeth that are visible by conventional light microscopy are composed of the same aggregated needle-like denticles that are found, often in large numbers, on the basal plates of many filospermoid species. 2) Other new ultrastructural tooth features include the tricuspid basal plate teeth in Problognathia minima, tripartite teeth in Austrognathia and Austrognatharia, and the clear separation, in the Gnathostomula basal plate, of a mediodorsal set of teeth from a more extensive rostroventral set. 3) Three rows of teeth, as typical for Gnathostomulidae and Austrognathiidae, are also present in the filospermoid Haplognathia filum. 4) The wide range of geographic variation in Haplognathia ruberrima is confirmed by significant differences in jaw teeth between specimens from Belize and Bermuda. 5) A compartmentalized involucrum is present in Labidgonathia longicollis. 6) A pair of lamellae addentales, until now only known from Valvognathia pogonostoma, was found in Tenuignathia rikerae, Problognathia minima, and probably also Labidognathia rikerae. 7) In all gnathostomulids, the lamella symphysis is composed of identical rods that are considered homologous with those in the mouth parts of Rotifera and Micrognathozoa., (Copyright 2002 Wiley-Liss, Inc.)

Gnathostomiasis is common in Southeast Asian countries and can be found sporadically in other parts of the world mainly due to human migration. The definitive diagnosis can be given either by identification of the parasite isolated from the patient or through histologic section of the lesion. It is therefore important for pathologists to be familiar with the morphology of parasitic larvae which varies according to the levels of section-cutting so that the diagnosis will not be misled. We present three cases of gnathostomiasis with different features of parasitic morphology and compare these with the reference adult worm.

Premolt, molting, and postmolt worms of Gnathostoma doloresi (Nematoda: Gnathostomatoidea) recovered from the stomach wall of naturally infected wild boars Sus scrofa leucomystax in Miyazaki, Japan, were examined morphologically. The only molt observed was that from the advanced third-stage to the adult stage. It is strongly suggested that the gnathostomes molt only once in the definitive host.

A new microscopic aschelminth-like animal, Limnognathia maerski nov. gen. et sp., is described from a cold spring at Disko Island, West Greenland, and assigned to Micrognathozoa nov. class. It has a complex of jaws in its pharynx, and the ultrastructure of the main jaws is similar to that of the jaws of advanced scleroperalian gnathostomulids. However, other jaw elements appear also to have characteristics of the trophi of Rotifera. Jaw-like structures are found in other protostome taxa as well-for instance, in proboscises of kalyptorhynch platyhelminths, in dorvilleid polychaetes and aplacophoran mollusks-but studies of their ultrastructure show that none of these jaws is homologous with jaws found in Gnathostomulida, Rotifera, and Micrognathozoa. The latter three groups have recently been joined into the monophylum Gnathifera Ahlrichs, 1995, an interpretation supported by the presence of jaw elements with cuticular rods with osmiophilic cores in all three groups. Such tubular structures are found in the fulcrum of all Rotifera and in several cuticular sclerites of both Gnathostomulida and Micrognathozoa. The gross morphology of the pharyngeal apparatus is similar in the three groups. It consists of a ventral pharyngeal bulb and a dorsal pharyngeal lumen. The absence of pharyngeal ciliation cannot be used as an autapomorphy in the ground pattern of the Gnathifera because the Micrognathozoa has the plesiomorphic alternative with a ciliated pharyngeal epithelium. The body of Limnognathia maerski nov. gen. et sp. consists of a head, thorax, and abdomen. The dorsal and lateral epidermis have plates formed by an intracellular matrix, as in Rotifera and Acanthocephala; however, the epidermis is not syncytial. The ventral epidermis lacks internal plates, but has a cuticular oral plate without ciliary structures. Two ventral rows of multiciliated cells form a locomotory organ. These ciliated cells resemble the ciliophores present in some interstitial annelids. An adhesive ciliated pad is located ventrally close to a caudal plate. As in many marine interstitial animals-e.g., gnathostomulids, gastrotrichs, and polychaetes-a special form of tactile bristles or sensoria is found on the body. Two pairs of protonephridia with unicellular terminal cells are found in the trunk; this unicellular condition may be the plesiomorphic condition in Bilateria. Only specimens with the female reproductive system have been found, indicating that all adult animals are parthenogenetic females. We suggest that 1) jaws of Gnathostomulida, Rotifera, and the new taxon, Micrognathozoa, are homologous structures; 2) Rotifera (including Acanthocephala) and the new group might be sister groups, while Gnathostomulida could be the sister-group to this assemblage; and 3) the similarities to certain gastrotrichs and interstitial polychaetes are convergent., (Copyright 2000 Wiley-Liss, Inc.)

To investigate the distribution of Gnathostoma spp in Ho Chi Minh City (HCM city), 1,081 eels were purchased from a local market twice a month from March 1998 to February 1999. Infective larvae of Gnathostoma spp detected from the flesh and liver of eels by the press preparation technique were examined and identified. Three hundred and fifty advanced third-stage larvae were recovered from liver, none from the flesh. The average rate of infection was 0.11; a high rate of infection was found from August to November and a low rate of infection from February to May. The average number of larvae/eel was 2.9; the greatest number of larvae/eel was in January whereas the lowest was in March and April. There was a marked decrease in both prevalence and intensity of infection from February to May, followed by a rise from June. The finding suggests that in HCM city, the infection rate abruptly decreases soon after the end of the rainy season and starts to rise when the rain comes and reaches its peak at the end of the rainy season. All recovered larvae were identified as G. spinigerum.

Gnathostomiasis caused by Gnathostoma doloresi Tubangui was observed in a 46-year-old Japanese man, a clerk, who resided in the Fukuoka prefecture of Kyushu district, in southern Japan. The first symptom noted by the patient was epigastric pain, which occurred 3 days after he had consumed the raw flesh of a brook trout, Oncorhynchus masou masou (Brevoort), from a trout farm in neighbouring Kumamoto prefecture. Three days later, he developed creeping eruptions on his trunk. The eruptions spread and the patient was admitted to hospital 18 days after eating the trout. No nematode larvae were found in any of four skin biopsies collected on admission. However, vesicles appeared on the lower abdomen of the patient 20 days after he had eaten the trout, and a small nematode was removed from one of them. One day after the nematode had been excised, a cutaneous swelling suddenly occurred on the patient's lower left jowl and this persisted for a week. All the skin abnormalities gradually decreased from day 25 post-ingestion and had disappeared by day 30. The isolated nematode was identified as an advanced third-stage larva of G. doloresi, based on its morphology and the number of hooklets on its head-bulb.

Human gnathostomiasis is well known to be caused by Gnathostoma spinigerum, G. hispidum, G. doloresi and G. nipponicum in Japan. In the present reported cases, skin biopsies were performed on three Japanese patients. As a result, cross sections of the larvae were clearly observed in the biopsied specimens. All cross sectioned larvae had an intestinal canal, which consisted from 25-35 cells. A large nucleus was observed at the center of each intestinal cell. The morphological features completely correlated with the characteristics of larval G. hispidum. Based on these findings, all three human cases were thus determined to be confirmed cases of gnathostomiasis caused by G. hispidum.

One thousand advanced third-stage larvae of Gnathostoma spinigerum from laboratory infected mice, two to five weeks after being fed with infected cyclops, were examined specifically for the morphology of their cephalic hooklets. Among these, only the 15-day old (early hepatic-stage) larvae and the 30-day old (late hepatic-stage) larvae were measured for the size of their body and hooklets. The average body size of the 15-day old and 30-day old larvae were 3.4 +/- 0.4 x 0.4 +/- 0.04 mm and 4.9 +/- 0.4 x 0.5 +/- 0.04 mm, respectively. The average size of the hooklets from rows one to four of the 15-day old larvae was 14.6 +/- 1.7 x 6.8 +/- 0.6 microm, 15.6 +/- 2.0 x 7.2 +/- 0.5 microm, 16.0 +/- 1.8 x 7.4 +/- 0.6 microm and 15.9 +/- 1.9 x 7.3 +/- 0.6 microm, respectively. Those of the 30-day old larvae were 15.1 +/- 1.7 x 7.1 +/- 0.6 microm, 16.3 +/- 1.6 x 7.5 +/- 0.7 microm, 16.5 +/- 1.7 x 7.8 +/- 0.6 microm and 16.3 +/- 1.7 x 7.6 +/- 0.8 microm, respectively. The average number of cephalic hooklets from rows one to four of the two- to five-week old larvae were 42.8 +/- 2.6, 45.3 +/- 2.8, 46.9 +/- 2.8 and 50.2 +/- 2.9, respectively. Several types of morphological variation and abnormality of the cephalic hooklets were observed. The most common ones were extra rudimentary hooklets below row four or within the four rows of hooklets (10.8%), the present of a fifth row of hooklets (1.9%), abnormal hooklets in only row four (1.2%), lobed or branched hooklets (0.5%), spiral arrangement of the four rows of hooklets (0.4%), and fragmented hooklets (0.4%).

The viscera of swamp eels were obtained from a local market in Bangkok twice a month from June 1996 to May 1997. The livers were separated, weighed and counted. Gnathostome larvae were recovered from the livers by the digestion technic, examined, identified, and counted. A total of 12,278 Gnathostoma larvae were obtained from 18,561.1 g (15,264 pieces) of eel livers. The overall average number of larvae/g liver and the overall average number of larvae/liver are 0.91 and 0.94, respectively. The greatest number of larvae/g liver (on average) was in December (high levels of infection during the months of October to December) whereas the lowest was in April (lowest levels of infection during the months of March to April). Thus there was a marked decrease in the average number of larvae/g liver during January to April, which then started to rise in May. This finding suggests that the level of infection abruptly decreases soon after the completion of the rainy season, starts to rise when the rain has come, and reaches its peak when the amount of rainfall is highest. More than 99% of the total gnathostome larvae recovered were identified to be G. spinigerum, and 25.4% of the entire larvae recovered bore variant or abnormal cephalic hooklets. The most common unusual feature was that there were extra rudimentary hooklets above row one, below row four and in between the four rows of hooklets which comprised 21.4%. In addition, the body size and the number of cephalic hooklets of G. spinigerum are also discussed.

To investigate the distribution of gnathostome worms in central Thailand, the infective larvae of Gnathostoma spp were examined from the flesh and liver of swamp eels, Fluta alba. Seven hundred and eighty-eight eels were purchased from markets in 11 provinces; Ang Thong (30), Ayutthaya (36), Chachoengsao (30), Lop Buri (30), Nakhon Nayok (437), Pathum Thani (30), Prachin Buri (48), Ratchaburi (53), Saraburi (30), Samut Prakan (30) and Suphan Buri (34). The highest rate of gnathostome infection was observed in swamp eels from Nakhon Nayok (68.7%). The infection rates in Ayutthaya, Ang Thong, Prachin Buri, Ratchaburi, Saraburi and Lop Buri were 33.3%, 26.7%, 25.0%, 18.9%, 13.3% and 10.0% respectively. Gnathostome larvae were not found in swamp eels from Chachoengsao, Pathum Thani, Samut Prakan and Suphan Buri. Among the 9,573 larvae recovered, almost all were the advanced third stage larvae of G. spinigerum, except one larva from Nakhon Nayok and two larvae from Ratchaburi which were identified as the advanced third stage larvae of G. vietnamicum and G. hispidum respectively. This study is the first report of swamp eels as natural intermediate hosts of G. vietnamicum and G. hispidum.

We observed the morphological characteristics and identified the species of gnathostome larvae obtained from the imported Chinese loaches. The early third-stage larvae (EL3) were collected from viscera of the loaches and a part of them were infected to mice. The advanced third-stage larvae [AdL3] were recovered from the mice at 4 weeks post-infection, both larval worms were fixed with 10% formalin, cleared in alcohol-glycerin solution, mounted with glycerin-jelly, and observed. A total of 369 EL3 were collected from viscera of 9,493 Chinese loaches. The whole body of EL3 was covered with about 190 transverse rows of minute cuticular spines and 0.624 x 0.101 mm in average size. A pair of lips were protruded at the anterior end, and the muscular esophagus and brownish intestine were followed. The characteristic head bulb was provided with 4 rows of hooklets. The average number of hooklets in the respective row was 36.7, 39.5, 41.6 and 44.3 posteriorly. AdL3 was 2.660 x 0.346 mm in average size, and retained the esophagus (about 0.755 mm length) and cervical sac (about 0.355 mm length). The average number of hooklets in the respective row on the head bulb was 39.0, 41.9, 43.9 and 45.6, posteriorly. On the basis of the morphological characteristics, they were identified as the third-stage larvae of Gnathostoma hispidum.

Five advanced third-stage larvae of a newly identified type of genus Gnathostoma were collected from freshwater eels, Fluta alba, which were purchased at a market in Nakhon Nayok, central Thailand. The most remarkable characteristic of the newly identified larvae was the larger body size compared with any other larva of Gnathostoma spp. They were also distinguishable from other species by the shape of their hooklets, which branched in a complex manner at the base: this had not been previously observed in any other larval Gnathostoma. The newly described larvae had an average number of 44.5, 45.0, 49.0 and 55.1 hooklets on the head-bulb from the first to the fourth rows, respectively, which were comparable to those of larval G. spinigerum. However, the average number of nuclei in each intestinal cell was 2.21 and fewer than those of the larvae of G. spinigerum. These results suggest that the new type of larvae belong to either G. vietnamicum, G. malaysiae, or constitute a new species of the genus Gnathostoma.

Six early third-stage larvae of Gnathostoma nipponicum were recovered from the muscle of 376 loaches, Misgurnus anguillicaudatus, imported from China. They were 614 x 114 microns in average size, almost colorless except brownish intestine, and encircled by about 229 transverse rows of minute cuticular spines. Their head bulbs provided with 3 rows of hooklets, of which average number were 34.5 on the first, 36.7 on the second and 39.7 on the third. Accordingly, it is revealed that the Chinese loach is a natural second intermediate host of G. nipponicum and G. nipponicum has been distributed somewhere in China. This parasite may infect human when the imported loaches are consumed raw.

Human gnathostomiasis is most frequently caused by the nematode Gnathostoma spinigerum. This disease is endemic to Southeast Asia, particularly Thailand and Japan. The clinical presentation is most commonly characterized by localized, intermittent, migratory swellings of the skin and subcutaneous tissues, often in association with localized pain, pruritus, and erythema. Since this worm can migrate to deeper tissues, any organ system may become involved. Characteristically, patients with gnathostomiasis have a moderate to severe elevation of the peripheral eosinophil count, with values not uncommonly exceeding 50% of the total white blood cell count. With modern-day travel and immigration, cases of gnathostomiasis are being diagnosed with increased frequency in the United States. Because of its rarity in this country, however, gnathostomiasis often is not included in an initial differential diagnosis despite the characteristic triad of intermittent migratory swelling, a history of travel to Southeast Asia, and eosinophilia. We report a case of cutaneous gnathostomiasis diagnosed in the United States, and we present a clinical review of the English-language literature on human gnathostomiasis.

A male Gnathostoma spinigerum was removed from the abdominal wall of a 29-year-old woman, who was in the habit of eating "naniura", a dish containing raw carp (Cyprinus carpio). After the removal of the worm she still had pain in her chest and noticed intermittent swelling of her right lower arm. Probably the patient still had one or more Gnathostoma worms migrating in her body.

Two human cases of gnathostomiasis from ingestion of raw native Japanese loaches, Misgurnus anguillicaudatus, are reported. Seven early third-stage larval Gnathostoma nipponicum were recovered from 3,098 loaches in the same district in which 2 human patients had obtained and eaten raw loaches. Encapsulated G. nipponicum larvae were also recovered from loaches infected under laboratory conditions. All 6 weasels captured in the same district in which the naturally infected loaches were found and where the humans had become infected were infected with adult worms of the same species. This is the first report of M. anguillicaudatus serving as a second intermediate host of G. nipponicum.

Since 1975, increasing numbers of patients with inflammatory, migrant, recidivant nodules were observed in the towns of Temazcal, state of Oaxaca, Tierra Blanca, Veracruz and others along the Papaloapan river. Larvae of Gnathostoma sp. have been obtained from some of them. The local species, although not completely identified, must be very close to G. spinigerum. Infection is related to ingestion of "ceviche", a very popular mexican delicacy made with raw Cyclid fishes of the Miguel Aleman dam. Ecological and social changes provoked by the construction of the dam and hypotheticaly related to the dissemination of the parasite are described. As the Temazcal Fish Culture Center has delivered tilapia fishes to many secondary culture centers, it is feared that the infection could spread through the country, so signs and symptoms of the disease are described in order to help Mexican doctors make the diagnosis if they were to encounter the disease.

A mass found in the stomach of a 10-year old cat contained a female worm of the genus Gnathostoma. The mass was described as a muscular pseudogranuloma induced by the worm. Although the worm species could not be ascertained, it was concluded that the cat served as an aberrant host for a Gnathostoma sp that usually infects wild mammals in the area.

Gnathostomiasis, usually caused by larvae of Gnathostoma spinigerum, is a significant cause of morbidity in the Far East. We report a case of gnathostomiasis involving a male Thai residing in Kuwait who presented with acute pain in the right iliac fossa. A resection of the terminal ileum and cecum was performed. Microscopic examination showed a parasite in an eosinophilic abscess. The nematode was identified as an immature male G. spinigerum based on size, morphology, and distribution of cuticular spines.

A 42-year-old Thai man from central Thailand came to Ramathibodi Hospital with the complaint of abdominal pain. Physical examination revealed localized tenderness in the right lower quadrant. The clinical impression was acute appendicitis and an operation was performed, revealing a large mass in the cecum. A right hemicolectomy was done for what was thought to be a carcinoma of the colon. The resected colon showed subserosal thickening on the antimesenteric side of the ascending colon with a constricted area at the middle portion. An immature adult Gnathostoma spinigerum was identified in the thickened subserosa of the cecum. Microscopic examination of the involved bowel showed a heavy infiltration of eosinophils, fibroblasts and histiocytes, and mild to moderate edema. The findings were consistent with eosinophilic granuloma of the gastrointestinal tract, and the presence of the parasite in the affected bowel suggested that it was the etiologic agent.

A living adult male Gnathostoma spinigerum was coughed up by a 33-year-old Thai married woman. The expectorated worm may have emerged from the pharynx. Pork is a possible source of infection in this case. The significant symptoms of her illness were migratory joint pain, chest pain, palpitation, and itchy throat, progressively. She has never had swellings.

Indirect fluorescent antibody test (IFAT) was performed on sections of Gnathostoma spinigerum advanced third-stage larva with gnathostomiasis, angiostrongyliasis, trichinosis, strongyloidiasis and cysticercosis sera. Positive fluorescence was observed with the first three sera. Fluorescence was associated with the anterior part of the esophagus, surface of the cuticle and cytoplasmic granules of the intestine. Absorption of sera with gnathostome antigen did not elicit fluorescence. The results suggest that substances secreted from the esophagus and intestine constitute antigens in excretory-secretory products of the larva.

Gnathostoma malaysiae Miyazaki and Dunn, 1965 was found in the stomach wall of Rattus surifer, captured in Phuket Island and Khao Yai National Park of Thailand. This is the first to be recorded in Thailand and the second discovery after the first description of Miyazaki and Dunn (1965). Pathological findings of infected animals were also described. Some new morphological descriptions were added to the original.

The recovery of six adult Gnathostoma spinigerum Owen, 1936 from a civet cat, Prionodon linsang Hardwick, constitutes the second reported record of this parasite and the first authenticated case of adult worms found in a wild animal from Malaysia. The food habits of the infected P. linsang as an important link in the transmission of G. spinigerum in the intermediate and definitive hosts together with the probable distribution of this parasite are discussed.

A male Gnathostoma spinigerum was removed from the cervix of a 29-year-old Jakarta resident who suffered from chronic cervicitis. The worm was 6.7 mm in length and had eight rows of spines on the cephalic bulb. This is the third case of gnathostomiasis reported from Indonesia.

A total of 23 gnathostome specimens different stages from the Hospital for Tropical Diseases, other general hospitals and medical clinics in Bangkok metropolitan area and central Thailand were identified as G. spinigerum. The various stages were as follows: Five advanced third-stage larvae (22.0%) of various sizes; 2.20-3.50 mm X 0.40-0.63 mm were removed from the skin, mucous membrane and the eyeball, of which the smallest measured 2.20 X 0.40 mm. Fourteen immature worms of both sexes were from the skin and mucous membrane, one spontaneously voided in the urine. The sizes varied from 4.63-9.35 mm X 0.60- 1.05 mm (8 male worms), and 3.83-16.25 mm. X 0.83-1.0 mm (6 female worms). All these immature worms had 8 rows of complete cephalic-hooklets with the exception of two with 6 and 7 rows of complete cephalic-hooklets. Four mature males size ranged from 9.9-12.5 mm X 1.0-1.25 mm. The smallest was removed from the abdominal skin of a newly born 7-day old baby evidently the case was prenatally transmitted.