Life cycle of Gnathostoma nipponicum Yamaguti, 1941

1992 ◽  
Vol 66 (1) ◽  
pp. 53-61 ◽  
Author(s):  
K. Ando ◽  
H. Tokura ◽  
H. Matsuoka ◽  
D. Taylor ◽  
Y. Chinzei

ABSTRACTThe life cycle of Gnathostoma nipponicum was examined by field survey and by experimental infection of animals with the larvae. Naturally infected larval G. nipponicum were found in loaches, catfish, and snakes. Experimentally, loaches, killifishes, frogs, salamanders, mice, and rats were successfully infected with the early third-stage larvae of G. nipponicum obtained from copepods (the first intermediate host), whereas snakes, quails, and weasels were not. Frogs, snakes, quails, and rats were experimentally infected with the advanced third-stage larvae (AdL3) from loaches. These results reveal that some species of fishes, amphibians and mammals can act as the second intermediate host and that some species of reptiles, birds and mammals can act as a paratenic host. The life cycle was completed in weasels, the definitive host, which were infected with AdL3 from loaches and started to evacuate eggs of G. nipponicum in faeces on days 65–90 postinfection.

1944 ◽  
Vol 22d (1) ◽  
pp. 6-16 ◽  
Author(s):  
Thomas W. M. Cameron

A trematode, widely distributed in Canada, and occurring in man and other fish-eating mammals, is described and its taxonomy discussed. Its life cycle has been worked out and it is shown to involve a snail, Amnicola limosa porata as first intermediate host and a fish, the common sucker (Catostomus commersonii) as the second intermediate host. The larval stages are described.


1978 ◽  
Vol 52 (3) ◽  
pp. 251-259 ◽  
Author(s):  
R. Madhavi

ABSTRACTThe life cycle of Genarchopsis goppo a hemiurid trematode found in the stomach of Channa punctata has been worked out in detail. The egg contains a fully developed miracidium at the time of liberation. The miracidium contains a ciliated covering, a long apical gland and a crown of spines at the anterior end. The snail Amnicola travancorica acts as the first intermediate host inside which the miracidium passes through sporocyst and redial generations. The cercaria is of cystophorous type and is identical to Cercariae Indicae Sewell XXXV. Metacercaria occurs in the ostracods Stenocypris malcolmsoni and Eucyoris capensis. The fish Aplocheilus panchax serves as the paratenic host. The entire developmental cycle from egg to egg producing adult takes 3 months.


Parasitology ◽  
1974 ◽  
Vol 68 (1) ◽  
pp. 1-12 ◽  
Author(s):  
R. A. Matthews

The cercaria and sporocyst of Bucephaloides gracilescens are described from Abra alba (Wood). Observations were made on the behaviour of the cercaria and the mechanism of release from the first intermediate host. The metacercaria was obtained experimentally for the first time using Ciliata mustela (L.), a species of Gadidae from rock pools, as second intermediate host. It has not previously been recorded from this fish. Unsuccessful attempts were made to infect species of fishes from three other families, namely, Bothidae, Pleuronectidae and Gobiidae, confirming the high degree of host specificity of the metacercaria to Gadidae. The metacercaria, its development and effect on the host are briefly discussed. It was linked with the adult on the basis of comparative morphology and ecology of the hosts.


1985 ◽  
Vol 33 (5) ◽  
pp. 715 ◽  
Author(s):  
TH Cribb

Opecoelus variabilis, sp. nov., is described from the intestine of 17 species of Australian freshwater fish. The highly variable anatomy of this species highlights the closeness of Opecoelus and Opegaster. Opegaster is made a synonym of Opecoelus and a new diagnosis is proposed for Opecoelus. The first intermediate host of O. variabilis is the prosobranch snail Posticobia brazieri, and the second intermediate hosts are five species of atyid, palaemonid and parastacid Crustacea. Features of the life cycle are the production of daughter sporocysts by the mother sporocyst when only one-quarter of its full size, and the further development of the metacercaria in the second intermediate host after becoming infective to the definitive host.


Author(s):  
Miriam Rothschild

If the number of infections with (a) trematode parthenitae and cercariae using Littorina neritoides as first intermediate host only, and (b) encysted metacercariae using L. neritoides as second intermediate host only, are plotted against the size of the snails, two different curves result. The first shows a low rate of infection in the small size groups, but a steep upward slope rising to 91% in the large size groups. The second shows a curve increasing uniformly to 87% infection.Possible interpretations are discussed, and it is concluded that the difference is probably due to the fact that primary infections cause accelerated growth in the host.


1987 ◽  
Vol 65 (10) ◽  
pp. 2491-2497 ◽  
Author(s):  
Murray J. Kennedy ◽  
L. M. Killick ◽  
M. Beverley-Burton

Life cycle studies of Paradistomum geckonum (Dicrocoeliidae) were attempted experimentally. The pulmonate gastropod Lamellaxis gracilis served as the first intermediate host; geckonid lizards (Cosymbotus platyurus, Gehyra mutilata, and Hemidactylus frenatus) served as definitive hosts. The life cycle of Mesocoelium sociale (Mesocoeliidae) was studied in naturally infected first intermediate hosts (L. gracilis, Huttonella bicolor) and experimentally in geckonid definitive hosts (C. platyurus, G. mutilata, and H. frenatus). Some naturally infected L. gracilis were infected concurrently with larval stages of both digeneans. Second intermediate hosts, presumed to be arthropods, were experimentally unnecessary. Metacercariae of P. geckonum were not found. Cercariae of M. sociale formed encysted metacercariae in the same individual snails.


1999 ◽  
Vol 73 (2) ◽  
pp. 143-145 ◽  
Author(s):  
A.M. McCarthy

The potential influence of second intermediate host species on the infectivity of metacercarial cysts of Echinoparyphium recurvatum to the definitive host Anas platyrhynchos was examined experimentally. Echinoparyphium recurvatum metacercarial cysts were obtained from the following experimentally infected second intermediate hosts 14 days post expsoure to cercariae: Lymnaea peregra; Physa fontinalis; L. stagnalis;Planorbis planorbis; Biomphalaria glabrata; tadpoles of the amphibian Rana temporaria. Metacercarial cysts from each of these hosts were fed, in doses of 50 cysts per individual, to separate groups composed of between four and eight, 3-day-old A. platyrhynchos ducklings. All A. platyrhynchos were necropsied 15 days post-infection and the number, size, and reproductive status of E. recurvatum worms in the intestine was recorded. Analyses of variance on the number (transformed log (x + 1)) and size of worms revealed no significant differences in worms originating from metacercariae formed in the different second intermediate hosts (worm number P > 0.05, and worm size P > 0.05). All worms recovered were found to be gravid. It is therefore concluded that the species of second intermediate host utilized does not influence the infectivity of the metacercarial cyst of E. recurvatum, nor the subsequent establishment and reproductive status of the parasite in A. platyrhynchos.


1992 ◽  
Vol 34 (4) ◽  
pp. 277-287 ◽  
Author(s):  
Dulcinéa Maria Barbosa Campos ◽  
Lindomar G. Freire Filha ◽  
Miguel Alípio Vieira ◽  
Julieta Machado Paçô ◽  
Moacir A. Maia

The life cycle of Lagochilascaris minor was studied using material collected from human lesion and applying the experimental model: rodents (mice, hamsters), and carnivorae (cats, dogs). In mice given infective eggs, orally, hatch of the third stage larvae was noted in the gut wall, with migration to liver, lungs, skeletal musculature and subcutaneous tissue becoming, soon after, encysted. In cats infected with skinned carcasses of mice (60 to 235 days of infection) it was observed: hatch of third stage larvae from the nodules (cysts) in the stomach, migration through the oesophagus, pharynx, trachea, related tissues (rhino-oropharynx), and cervical lymphonodes developing to the mature stage in any of these sites on days 9-20 post inoculation (P.I.). There was no parasite development up to the mature stage in cats inoculated orally with infective eggs, which indicates that the life cycle of this parasite includes an obligatory intermediate host. In one of the cats (fed carcass of infected mice) necropsied on day 43 P.I., it was observed the occurence of the self-infective cycle of L. minor in the lung tissues and in the cervical region which was characterized by the finding of eggs in different stages of development, third stage larvae and mature worms. It's believed that some component of the carnivorae gastrointestinal tracts may preclude the development of third stage larvae from L. minor eggs what explains the interruption of the life cycle in animals fed infective eggs. It's also pointed out the role of the intermediate host in the first stages of the life cycle of this helminth.


2005 ◽  
Vol 79 (2) ◽  
pp. 169-176 ◽  
Author(s):  
J.A. Shears ◽  
C.R. Kennedy

AbstractPrevious studies on the life history of the nematode eel specialist Paraquimperia tenerrima (Nematoda: Quimperiidae) have failed to determine whether an intermediate host is required in the life cycle. In the laboratory, eggs failed to hatch below 10°C, hatching occurring only at temperatures between 11 and 30°C. Survival of the free-living second stage larvae (L2) was also temperature dependent, with maximal survival between 10 and 20°C. Total survival of the free-living stages (eggs and L2) is unlikely to exceed a month at normal summer water temperatures, confirming that parasite could not survive the 6 month gap between shedding of eggs in spring and infection of eels in early winter outside of a host. Eels could not be infected directly with L2, nor could a range of common freshwater invertebrate species. Third stage larvae (L3) resembling P. tenerrima were found frequently and abundantly in the swimbladder of minnows Phoxinus phoxinus from several localities throughout the year and were able to survive in this host in the laboratory for at least 6 months. Third stage larvae identical to these larvae were recovered from minnows experimentally fed L2 of P. tenerrima, and eels infected experimentally with naturally and experimentally infected minnows were found to harbour fourth stage larvae (L4) and juvenile P. tenerrima in their intestines. Finally, the whole life cycle from eggs to adult was completed in the laboratory, confirming that minnows are an obligate intermediate host for P. tenerrima.


Parasitology ◽  
1982 ◽  
Vol 84 (1) ◽  
pp. 131-135 ◽  
Author(s):  
R. Vanoverschelde

SUMMARYThe influence of temperature and salinity on miracidial longevity and miracidial infectivity of the digenean,Himasthla militaris, has been examined. At 14, 25 and 30 °C the half-life of the miracidia was 1200, 630 and 420 min respectively, and infection of the first intermediate host,Hydrobia ventrosa, only occurred at 25 and 30 °C, for both temperatures 52% became infected. In the range 2·1 to 34‰ (2·1, 4·2, 8·5, 17 and 34‰) the miracidia had a minimal and maximal half-life of 60 and 630 min in water with a salinity of 2·1 and 17‰ respectively, while the infection of the snail host was possible only in water with a salinity of 8·5 and 17‰.


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