Number Of Hooklets Research Articles

Infection Status of Gnathostoma spinigerum Larvae in Asian Swamp Eels, Monopterus albus, Purchased from Local Markets in Cambodia.

Present study was performed to know the infection status of Gnathostoma sp. larvae in swamp eels from Cambodia. We purchased total 30 Asian swamp eels, Monopterus albus, from local markets in Pursat and Takeo Provinces and Phnom Penh on May and November 2017 and May 2018. All collected eels were transferred to our laboratory with ice and each of them was examined by artificial digestion method. A total of 15 larval gnathostomes (1–5 larvae) were detected from 55.6% (5/9) swamp eels in Pursat Province. No larval gnathostomes were found in 21 swamp eels in Takeo Province and Phnom Penh. The advanced third-stage larvae (AdL3) detected were 2.575–3.825 (3.250) mm in length and 0.375–0.425 (0.386) mm in width. They had the characteristic head bulb (av. 0.104×0.218 mm) with 4 rows of hooklets, long muscular esophagus (1.048 mm), and 2 pairs of cervical sacs (0.615 mm). The number of hooklets in 4 rows on the head bulb was 41, 44, 47, and 50. In scanning electron microscopy, characteristic features were 4 rows of hooklets on the head bulb, cervical papillae, tegumental spines regularly arranged in transverse striations, and anus. The larval gnathostomes were identified as AdL3 of Gnathostoma spinigerum based on the morphological characters. By the present study, it has been confirmed that G. spinigerum larvae are infected in Asian swamp eels, M. albus, in Pursat Province, Cambodia.

Stenochironomus munteanpurin sp. n., a new leaf-mining species from Brazil (Diptera: Chironomidae).

Stenochironomus munteanpurin sp. n. is described and illustrated in all life stages, except eggs, from Brazil. The male is very similar to Stenochironomus quadrinotatus Borkent, 1984 due to same overall pattern of pigmentation. The new species can be distinguished from the other related species principally in immature stages: larva with labral lamella arranged in two groups with one or two conical-shaped teeth, spicules of pecten epipharyngis arranged in a row, unequal and irregularly distributed sizes, SI bifurcated, SII pinnate, SIII pinnate setae and, larval exuviae is compacted; pupa with shagreens being in all TI, less number of hooklets in TII, TVII without shagreens and presence of shagreen in conjunctive III/IV and IV/V. Adult male is very similar to the one of S. quadrinotatus but can be distinguished by combination of the TIX with more than 25 setae medially and phallapodeme curved anteriorly. The new species were collected in the following Brazilian states: Rio de Janeiro, Santa Catarina, Bahia and Acre.

Halysioncum kishiense sp. n. and Echinobothrium parsadrayaiense sp. n. (Cestoda: Diphyllidea) from the banded eagle ray, Aetomylaeus cf. nichofii off the Iranian coast of the Persian Gulf

Two new species of two genera of the order Diphyllidea van Beneden in Carus, 1863, Halysioncum Caira, Marques, Jensen, Kuchta et Ivanov, 2013 and Echinobothrium van Beneden, 1849 sensu stricto are described from Aetomylaeus cf. nichoffi (Bloch et Schneider) off the Iranian coast of the Persian Gulf. Halysioncum kishiense sp. n. differs from all other congeners in the number of apical hooks with the exception of H. hoffmanorum (Tyler, 2001) and H. pigmentatum (Ostrowski de Núñez, 1971). Halysioncum kishiense sp. n. can be easily differentiated from H. hoffmanorum and H. pigmentatum by the number of hooklets and testis numbers. Echinobothrium parsadrayaiense sp. n. is differentiated from all its congeners except for E. acanthinophyllum Rees, 1961 by its hook formula. The number of spines per column on the cephalic peduncle, the number of testes and possession of a thick-walled rather than thin-walled vagina distinguish E. parsadrayaiense sp. n. from E. acanthinophyllum. To date, with these two new species, five species of Diphyllidea have been reported from the Persian Gulf.

Description of Three New Species of Echinobothrium (Cestoda: Diphyllidea) from Indo-Pacific Elasmobranchs of the Genus Glaucostegus (Rajiformes: Rhinobatidae)

Three new species of diphyllidean cestodes are described from rhinobatid elasmobranchs of the genus Glaucostegus from the Indian and Pacific Oceans. All 3 new species have 11 apical hooks (6 type-A and 5 type-B hooks) and, therefore, differ in this feature from all but 5 of the 39 valid species of Echinobothrium. In addition, Echinobothrium tetabuanense n. sp. from Glaucostegus cf. typus in the Sulu Sea, Borneo differs from all of its congeners in the number and arrangement of hooklets, number of spines on the cephalic peduncle, and the number and distribution of testes. Echinobothrium sematanense n. sp. from Glaucostegus thouin in the South China Sea, Borneo, can be distinguished from its congeners based on the following combination of characters, i.e., small size (worms less than 1 mm long), number of hooklets, spines per column on the cephalic peduncle, and number of testes. Echinobothrium weipaense n. sp. from northern Australia is unique in the position of the cirrus sac and genital pore, both structures being well posterior and not overlapping the ovary. An emended description of the microthrix pattern on the scolex of Echinobothrium chisholmae from G. typus in Australia is also presented.

Discovery of LarvalGnathostoma nipponicumin Frogs and Snakes from Jeju-do (Province), Republic of Korea

A survey was performed to find out the intermediate hosts of Gnathostoma nipponicum in Jeju-do (Province), the Republic of Korea. In August 2009 and 2010, a total of 82 tadpoles, 23 black-spotted pond frogs (Rana nigromaculata), 7 tiger keelback snakes (Rhabdophis tigrinus tigrinus), 6 red-tongue viper snakes (Agkistrodon ussuriensis), and 2 cat snakes (Elaphe dione) were collected in Jeju-do and examined by the pepsin-HCl digestion method. Total 5 gnathostome larvae were detected in 3 (50%) of 6 A. ussuriensis, 70 larvae in 3 of 7 (42.9%) R. tigrinus tigrinus, and 2 larvae in 2 of 82 (8.7%) frogs. No gnathostome larvae were detected in tadpoles and cat snakes. The larvae detected were a single species, and 2.17×0.22 mm in average size. They had characteristic head bulbs, muscular esophagus, and 4 cervical sacs. Three rows of hooklets were arranged in the head bulbs, and the number of hooklets in each row was 29, 33, and 36 posteriorly. All these characters were consistent with the advanced third-stage larvae of G. nipponicum. It has been first confirmed in Jeju-do that R. nigromaculata, A. ussuriensis, and R. tigrinus tigrinus play a role for intermediate and/or paratenic hosts for G. nipponicum.

Three new species of Echinobothrium (Cestoda: Diphyllidea) from Indo-Pacific stingrays of the genus Pastinachus (Rajiformes: Dasyatidae)

Three new species of diphyllidean cestodes are described from stingrays of the genus Pastinachus from the Indian and Pacific Oceans. All three new species differ from all but 10 of the 36 valid species of Echinobothrium van Beneden, 1849 in that they bear lateral hooklets arranged in a continuous band across each lateral surface of the rostellum joining the groups of dorsal and ventral apical hooks, rather than arranged in distinct dorsal and ventral groups, on each side of the apical hooks. Echinobothrium nataliae sp. n. ex Pastinachus solocirostris off Borneo differs from other relatives in the following combination of characters: number of spines in each column on the cephalic peduncle, number of lateral hooklets and number of apical hooks. Echinobothrium reginae sp. n. ex Pastinachus cf. sephen off Madagascar differs from all congeners in the following combination of characters: number of hooklets and number of spines on the cephalic peduncle. Echinobothrium vojtai sp. n. from an undescribed species of Pastinachus off Borneo differs from its congeners in the following combination of characters: number of hooklets, number of apical hooks and number of spines in each column on the cephalic peduncle. The hook formula was modified to accommodate species with lateral hooklets arranged in a continuous band as follows: {(LH) AH(A)/AH(B)}, where (LH) is the total number of lateral hooklets in a band. A table of all nominal species of Echinobothrium, showing their taxonomic status, type host and locality, number of peduncle spines in a column and hook formula, is presented. Macrobothridium djeddensis and Macrobothridium sinensis are transferred to Echinobothrium. In addition, Echinobothrium deeghai is considered as a species inquirenda.

Description and development of the early third-stage larva of Gnathostoma turgidum Stossich, 1902 (Nematoda: Gnathostomatidae) and contributions to its life cycle

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.

Detection of Gnathostoma spinigerum Third-Stage Larvae in Snakeheads Purchased from a Central Part of Myanmar

To examine the infection status of freshwater fish with Gnathostoma spp. larvae in Myanmar, we purchased 15 snakeheads, Channa striatus, from a local market in a suburban area of Naypyidaw, the new capital city. Two larval gnathostomes were collected using an artificial digestion technique, and observed by a light microscope and a scanning electron microscope. The size of an intact larva was 2.65 mm long and 0.32 mm wide. The characteristic morphology of the larvae included the presence of a long esophagus (0.80 mm long), 2 pairs of cervical sacs (0.43 mm long), and a characteristic head bulb with 4 rows of hooklets. The number of hooklets in the 1st, 2nd, 3rd, and 4th row was 45, 48, 50, and 52, respectively. Based on these morphological characters, the larvae were identified as the advanced 3rd-stage larvae of Gnathostoma spinigerum. This is the first report of detection of G. spinigerum 3rd-stage larvae in the central part of Myanmar. Our study suggests that intake of raw meat of snakehead fish in Myanmar may result in human gnathostomiasis.

Human gnathostomiasis caused by Gnathostoma doloresi, with particular reference to the parasitological investigation of the causative agent

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.

Echinobothrium notoguidoi n. sp. (Cestoda: Diphyllidea) from Mustelus schmitti (Chondrichthyes: Carcharhiniformes) in the Argentine Sea

A new cestode, Echinobothrium notoguidoi n. sp., is described from the spiral intestine of the shark Mustelus schmitti, from coastal waters off Mar del Plata, Argentina. This species is distinguished from all others in the genus by a rostellar armature consisting of 2 apical groups of 31 large hooks each, arranged in 2 rows (16 anterior, 15 posterior) with 13 hooklets per side, a wide corona of 8-11 rows of spines posterior to the rostellum, 8 rows of 24-26 spines on the cephalic peduncle, and 11-15 testes per proglottid. The new species most closely resembles 2 congeners that also parasitize sharks, Echinobothrium musteli and Echinobothrium scoliodoni, on the basis of the armature of the rostellum and cephalic peduncle and the presence of a corona of small spines. Echinobothrium notoguidoi can be differentiated from E. musteli by the number of hooklets (3) and testes (22), and from E. scoliodoni by the number of large hooks (10-13), spines on the cephalic peduncle (> 100), and segments (40-50). Echinobothrium notoguidoi is clearly distinguished from Echinobothrium pigmentatum described previously from Zapteryx brevirostris in Argentine waters by the following combination of characters: corona of hooks lacking, possession of fewer apical hooks (20), hooklets in a continuous row instead of separate groups, fewer spines in the cephalic peduncle (9-13 per row), and fewer testes (5-7) per proglottid.

Early third-stage larvae of Gnathostoma hispidum in cyclops

Surface structures of the early third-stage larvae were examined by scanning electron microscopy. There were hemispherical head-bulbs at the apical ends. These bulbs could be clearly distinguished from the bodies. The head-bulbs (52 X 29 micron) had four transverse rows of sharp hooklets. The number of hooklets in each row was 37, 36, 38, and 43, posteriorly. The larvae posessed a pair of lateral lips in the head-bulb. Each of the lips had two labial papillae and an amphid between the papillae. Small unidentate cuticular spines were present along the entire length of larvae on their transverse striations. The number of these cuticular striations was 175-217. A pair of cervical papillae and an excretory pore were present on the anterior part of the body. Another pair of papillae was detected laterally on the posterior one-third of the body. The shape of the posterior body papillae resembled that of cervical papillae. The cuticular spines were absent around the anus.