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1.
Neodiplostomula from the European grass snake Rhabdophis tigrina, in the Republic of Korea, were thought to represent 2 species: Pharyngostomum cordatum (large-sized neodiplostomula), an intestinal trematode of cats, and Neodiplostomum seoulense (small-sized neodiplostomula), an intestinal trematode of humans and rodents. The present study describes N. leei n. sp. (Digenea: Neodiplostomidae) on the basis of adult flukes recovered from the small intestines of chicks experimentally infected with small-sized neodiplostomula from the grass snake. The new species differs from N. seoulense in terms of the more extensive distribution of vitellaria, the more severe bilobation of 2 testes (each having a dumbbell shape), the absence of a genital cone, and the smaller size of the tribocytic organ and eggs. Neodiplostomula of the new species and N. seoulense are almost indistinguishable. The new species develops into an adult in chicks, whereas N. seoulense matures in mice and rats. Neodiplostomula of the new species migrate to the liver in mice and rats, without maturing. Results show that there are at least 3 species of neodiplostomid trematodes in the grass snake in the Republic of Korea, i.e.. P. cordatum, N. seoulense and N. leei n. sp. 相似文献
2.
Three species of neodiplostomula are known to inhabit the European grass snake, Rhabdophis tigrina, in the Republic of Korea: Pharyngostomum cordatum (large-sized neodiplostomula), an intestinal trematode of cats; Neodiplostomum seoulense (small-sized neodiplostomula), an intestinal trematode of humans and rodents; and Neodiplostomum leei (small-sized neodiplostomula), which migrates to the livers of rodents and is an intestinal trematode of birds. The present study describes a fourth species, Neodiplostomum (Conodiplostomum) boryongense n. sp. (Digenea: Neodiplostomidae), based on adult flukes recovered from the small intestines of chicks experimentally infected with small-sized neodiplostomula from the grass snake. The new species differs from 13 previously known species. It also differs from N. seoulense in its larger body size, severely bilobed testes, and smaller genital atrium, and from N. leei in its larger body size, smaller ventral sucker, presence of a genital cone, and vitelline follicles distributed chiefly in the forebody. The new species does not migrate to the livers of rodents nor does it develop to adulthood in the rodent intestines. However, the neodiplostomula of the new species are indistinguishable from those of the other 2 species. Results show that at least 4 species of neodiplostomula inhabit the grass snake in the Republic of Korea. 相似文献
3.
Extraintestinal migration patterns of Pharyngostomum cordatum (Digenea: Neodiplostomidae) were studied in experimental rodents such as mice, rats, and hamsters. When metacercariae isolated from grass snakes were infected orally to rodents, they penetrated the intestinal wall at days 2-3 post-infection (p.i.) and were discovered mainly in the diaphragm, intercostal muscles, and vital organ such as the lungs at days 7-28 p.i., without morphological changes. Interestingly, from several rodents which died suddenly at days 2-9 p.i., small to considerable numbers of metacercariae were found, not only in the lungs, but also in the heart and brain. Within the tissues, worms were freely motile until day 7 p.i., but later they were surrounded by host cells, and finally tissue cysts were formed. When metacercariae harvested from the snakes and intercostal muscles of rodents were infected orally to cats, they developed into adult flukes in the small intestine. The results show that P. cordatum undergoes considerable extraintestinal migration including the vital organs of its rodent hosts. 相似文献
4.
A total of 19 species of food-borne intestinal trematodes have been reported in humans in the Republic of Korea. They include 12 species of the Heterophyidae, Metagonimus yokogawai, M. takahashii, M. miyatai, Heterophyes nocens, H. heterophyes (imported), H. dispar (imported), Heterophyopsis continua, Pygidiopsis summa, Stellantchasmus falcatus, Centrocestus armatus, Stictodora fuscata, and S. lari; four species of the Echinostomatidae, Echinostoma hortense, E. cinetorchis, Echinochasmus japonicus, and Acanthoparyphium tyosenense; and one species each of the Neodiplostomidae, Neodiplostomum seoulense, Plagiorchiidae, Plagiorchis muris, and Gymnophallidae, Gymnophalloides seoi. Fresh water fish harbor the metacercarial stage of M. yokogawai, M. takahashii, M. miyatai, C. armatus, E. hortense, E. cinetorchis, E. japonicus, or P. muris. Brackish water fish serve as the second intermediate hosts for H. nocens, H. continua, P. summa, S. falcatus, S. fuscata, and S. lari. Brackish water bivalves are the source of infection with A. tyosenense. Tadpoles and frogs are the second intermediate hosts for N. seoulense, but the major source of human infection is the grass snake Rhabdophis tigrina, a paratenic host. The metacercariae of G. seoi are observed in oysters. The natural definitive hosts are, in most cases, mammals such as rats, cats and dogs. However, several species (C. armatus, S. lari, E. japonicus, A. tyosenense, and G. seoi) have birds as natural definitive hosts. Host-parasite relationships, pathogenesis and pathology, immunity, clinical aspects, differential diagnosis, treatment, prevention and control of these intestinal trematodes are briefly discussed. 相似文献
5.
蛇胸腺胚胎发育的组织学研究 总被引:1,自引:0,他引:1
该文应用光镜、电镜和细胞计数技术对胚胎发育期虎斑颈槽蛇胸腺的发育分化进行了研究。在胚胎发育11期,胸腺原基内出现前淋巴细胞。从胚胎发育12期至出生前(16期),淋巴细胞不断增殖分化,小淋巴细胞逐渐增多,而淋巴母细胞和中淋巴细胞逐渐减少。胸腺皮质和髓质形成于16期。巨噬细胞以及肌样细胞和胸腺APUD细胞分别形成于胚胎发育14期和15期,随后数量有所增加,分别分布于胸腺皮质和髓质。 相似文献
6.
Shin EH Kim IM Kim JL Han ET Park YK Nawa Y Kook J Lee SH Chai JY 《The Journal of parasitology》2006,92(2):223-229
Of morphologically indistinguishable small-sized neodiplostomula in the grass snake Rhabdophis tigrina in the Republic of Korea, some, such as Neodiplostomum seoulense, mature into adults in the intestines of rodents, whereas others, such as Neodiplostomum leei, migrate to rodent livers and mature in the intestines of chicks. In the present study, we aimed to observe in more detail the extraintestinal migration and development of N. leei by using various animal models, i.e., mice, rats, hamsters, rabbits, cats, and chicks. In mammals, small-sized neodiplostomula (N. leei) inoculated orally penetrated the intestinal wall, entered the peritoneal cavity, and oriented to the liver without passing through any other organ. In rodent livers, the neodiplostomula were surrounded by host inflammatory cells and fibrotic tissues from day 10 postinfection (PI); the worms were found dead by day 56 PI. When neodiplostomula from rodent livers were transferred orally to mammals, they reoriented to the liver, although they were able to develop into adults in the chick intestine by day 6-7 PI. The possibility of human infections, i.e., liver migration, by N. leei neodiplostomula, among snake consumers, warrants investigation. 相似文献
7.
This study was performed to observe the susceptibility of dogs and cats as definitive hosts of Paragonimus iloktsuenensis. The metacercariae of this fluke were obtained from Sesarma dehaani collected at a focus near the mouth of Sumjin river in November, 1986 and February, 1987. The larvae isolated from the crabs were introduced per os into 7 albino rats, 2 dogs and 3 cats. The adults were recovered from the experimental animals, and they were morphologically observed and measured. The results were as follows: 1. The recovery rate of adult worms at 42 days after infection was 53.3% from three albino rats, 21.0% from a dog and 12.7% from two cats. Most of the worms were recovered from the worm capsules in the lungs. 2. The size of worms recovered from albino rats, a dog, and cats 42 days after infection averaged 6.3 x 3.2 mm, 6.3 x 3.0 mm, or 6.2 x 3.5 mm, respectively. There were little differences in the morphology of worms by different experimental animals. 3. The size of eggs from a dog was 88.9 x 49.3 microns, and that from cats was 84.3 x 53.7 microns on average. Dogs and cats were good definitive hosts of P. iloktsuenensis. This fact suggests that human infection by this fluke may be possible if the metacercariae were ingested. 相似文献
8.
The surface ultrastructure of advanced third-stage larvae (AL3) of Gnathostoma nipponicum was studied using scanning electron microscopy. The larvae were recovered from the grass snake Rhabdophis tigrina in the Republic of Korea. Parasites had a globular head bulb with a pair of lips at the anterior end and 2 labial papillae and an amphid on each lip. The head bulb was characteristically armed with 3 transverse rows of hooklets, averaging 36, 38, and 43 in number, increasing posteriorly. A total of 213-232 minute unidentate cuticular spines were present along the entire length of the larvae, forming the transverse striations. Two pairs of cervical papillae were located between the 8th and 12th transverse striations, and a pair of body papillae was seen laterally on the posterior third of the body. A pair of caudal phasmids was recognized near the posterior extremity. The surface ultrastructure of AL3 of G. nipponicum is unique compared with that of other species. 相似文献
9.
To investigate the relationship between structure and function of the deferens ducts in the Chinese rat snake (Zaocys dhumnades), morphological changes within an annual cycle were observed by routine histological techniques. Also, the correlation of androgen receptor (AR), estrogen receptor (ER), progesterone receptor (PR) and aromatase (Ar) expressions in the vas deferens and testis were studied immunohistochemically. To confirm that the sperm and the spherical structure existed in deferens ducts, we also used routine histological technique observed deferens ducts in the Striped-tailed rat-snake (Elaphe taeniura), Red-banded snake (Dinodon rufozonatum), and Tiger-spotted neck-troughed snake (Rhabdophis tigrina lateralis). The results showed that the deferens ducts of the Chinese Rat Snake were composed of efferent duct, epididymal duct and vas deferens. Efferent duct contained sperm from August-October, and the sperm were observed in the epididymal duct from August-the following January. Throughout the year (except July) a large number of sperm were present in the vas deferens where a previously unreported spherical structure formed by spermatids was observed, which showed no significant differences in the IOD values of AR-, ER-, PR- and Ar-immunoreactivities. Since the spermatids in the spherical structure were undergoing spermatogenesis and this phenomenon also existed in the Striped-tailed rat-snake and Red-banded snake, the term, seminiferous spherule, was named for this spherical structure This study demonstrated that the testis was the main site for snake spermiogenesis, and the seminiferous spherule in vas deferens was the other Both the epididymis and vas deferens stored sperm; however, the vas deferens was the main organ for sperm storage. 相似文献
10.
Laboratory-reared planarians, Dugesia tigrina, were exposed to cercariae of Echinostoma trivolvis or Echinostoma caproni. Of 100 D. tigrina exposed to 2,750 cercariae of E. trivolvis, 29 were infected with a total of 85 encysted metacercariae 24 hr postinfection (PI). None of 40 D. tigrina exposed to 1,100 cercariae of E. caproni was infected with metacercariae 24 hr PI. Cyst structure of E. trivolvis from the parenchyma of D. tigrina varied from normal to abnormal. Metacercariae removed from planarians could be excysted in an alkaline trypsin-bile salts medium. Cercariae of E. trivolvis were not attracted to dialysate material from D. tigrina. Cercariae of E. trivolvis that penetrated, but did not encyst in planarians, voided the contents of their paraesophageal glands. Cercariae of E. caproni lack paraesophageal glands. Secretions of those glands probably are involved in tissue penetration of D. tigrina by E. trivolvis cercariae. 相似文献
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Shigehisa Habe Pham Ngoc Doanh Shinichiro Yahiro Nanthasane Vannavong Hubert Barennes Peter Odermatt Gilles Dreyfuss Yoichiro Horii Yukifumi Nawa 《The Korean journal of parasitology》2013,51(6):683-687
Among Paragonimus species, P. paishuihoensis is one of the most mysterious and poorly understood species. Metacercariae are characterized by having a unique dendritically branched excretory bladder. However, the morphology of the adult worm remains unknown. To date, metacercariae of this species have been reported only in China and Thailand. In this study, we first found P. paishuihoensis metacercariae in freshwater crabs, Potamon lipkei, in Hinheub District, Vientiane, Lao PDR, with a prevalence of 77.7% and the average intensity of 10.3 (range 1-28) metacercariae per crab. The molecular data based on ITS2 and CO1 markers indicated that P. paishuihoensis from Laos and Thailand were almost completely identical and were close to members of the Paragonimus bangkokensis/Paragonimus harinasutai complex. Attempts to infect experimental animals (cats, dogs, and rats) with P. paishuihoensis were unsuccessful, suggesting that these animals might be unsuitable definitive hosts for the species. Further studies are necessary to elucidate the taxonomic status and life cycle of P. paishuihoensis. 相似文献
13.
虎斑颈槽蛇是中国数量较多、分布最广的蛇类之一,但一直被当作无毒蛇而忽视。为了使人们对虎斑颈槽蛇有一个全面、正确的认识,也为以后的相关研究奠定一定的理论基础,从虎斑颈槽蛇的分布,形态,生活习性以及毒腺的研究等方面加以综述。 相似文献
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A study was made to observe the effect of cobalt-60 irradiation on the viability of Paragonimus westermani metacercariae in Sinopotamon chekiangense crabs. The crabs were collected in mountain regions of the Zhejiang Province of China in which paragonimiasis is endemic. Adult cats and albino mice were infected with metacercariae irradiated at different doses. Dissection of the host animals was conducted 90 or 30 days, respectively, after infection for recovery of lung flukes. Anti-metacercariae antibody in infected mice was measured by enzyme-linked immunosorbent assay (ELISA). Results showed that metacercariae were unable to grow into adult worms in cats after exposure to gamma irradiation at a dose of 0.10 kGray. However, a small number of metacercariae exposed to a dose of 2.0 kGray excysted and survived in 1 mouse for 30 days. No worm was recovered from mice when the metacercariae were irradiated at a dose of 2.5 kGray. Seropositive results by ELISA were obtained when the mice were infected with metacercariae irradiated at doses ranging from 2.0 to 3.5 kGray. 相似文献
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The life-cycle of Pleurogenoides ovatus Rao, 1977, infecting the frogs, Rana tigrina and R. cyanophlyctis has been elucidated. All the life-cycle stages from egg to egg-producing adults were successfully established in the laboratory. The life-cycle took about 80 days for completion. Cercariae were found in the freshwater snail. Digoniostoma pulchella, collected from paddy fields at Chelembra, Malappuram district of Kerala, during the monsoon months. Cercariae are of the virgulate xiphidiocercous type. Metacercariae occurred in the connective tissues, hepatopancreas and musculature of the freshwater crab, Paratelphusa hydrodromous. The growth and development of the metacercariae in P. hydrodromous have been studied in detail. Frogs became infected when they fed on infected crabs. The prepatent period is 10 days. 相似文献
18.
长期以来,人们仅把具有沟牙和管牙的蛇视为毒蛇,然而,近年来发现游蛇科中的虎斑颈槽蛇、红脖颈槽蛇、颈棱蛇、赤链蛇等既无管牙,也无沟牙,却频频发生这类蛇咬伤人后引起中毒的事例,甚至出现被咬伤致严重出血休克死亡的事件。经深入研究后发现,这些蛇虽没有沟牙和管牙,但却具有产生毒性分泌物的毒腺—杜氏腺(Duvernoy′s gland)及皮下腺,且不同的毒腺具有不同的毒性作用,可表现为出血不止、溶血、呼吸困难、肾损害等。这类蛇与毒腺的导管有联系的上颌牙明显粗大,上颌牙与上颌骨、横骨连接牢固,毒腺里的毒液可顺着粗大的上颌牙流入伤口,因此,应视为"后毒牙类毒蛇"。 相似文献
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