The Life Cycle and Biology of Opecoelus Variabilis, Sp.nov. (Digenea: Opecoelidae).

1985 ◽  
Vol 33 (5) ◽  
pp. 715 ◽  
Author(s):  
TH Cribb
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Intermediate Hosts ◽  
Full Size ◽  
Second Intermediate Host ◽  
New Diagnosis ◽  
Australian Freshwater ◽  
Further Development ◽  
First Intermediate Host ◽  
Prosobranch Snail

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.

The Life-Cycle and Morphology of Stemmatostoma-Pearsoni, Gen Et Sp-Nov, With Notes on the Morphology of Telogaster-Opisthorchis Macfarlane (Digenea, Cryptogonimidae)

1986 ◽  
Vol 34 (2) ◽  
pp. 279 ◽  
Author(s):  
TH Cribb
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Freshwater Fish ◽  
Oral Sucker ◽  
Intermediate Hosts ◽  
Redial Generation ◽  
Adult Morphology ◽  
Mother Sporocyst ◽  
First Intermediate Host ◽  
Prosobranch Snail

Stemmatostoma pearsoni, gen. et sp. nov., is described from the intestine of Leiopotherapon unicolor (Gunther) and Macquaria novemaculeata (Steindachner) in Queensland. Stemmatostoma is placed within the Neochasminae and is distinguished by its long oesophagus, compact ovary, short caeca, pre-ovarian vitellaria, simple gonotyl and funnel-shaped oral sucker. The diagnosis of the Neochasminae is emended excluding Parspina Pearse. Telogaster opisthorchis Macfarlane is recorded from the intestine of Anguilla reinhardtii Steindachner from Victoria. The spinose oral suckers of S. pearsoni and T. opisthorchis are capable of being retracted into tegumental pockets. It is postulated that this arrangement may be widespread amongst spinose cryptogonimids. The first intermediate host of S. pearsoni is Posticobia brazieri (Smith), a prosobranch snail. The second intermediate hosts are freshwater fish: Hypseleotris galii (Ogilby), H. compressus (Krefft), Mogurnda mogurnda (Richardson), M. adspersa (Castelnau), Philypnodon grandiceps (Krefft), Gobiomorphus australis (Krefft), and Pseudomugil signifer Kner. Within the snail there is a mother sporocyst generation, a redial generation and a cercarial generation. Development of the mother sporocyst is similar to that described for other opisthorchioids. Cryptogonimid cercariae are characterized by 16 flame-cells, pre-vesicular penetration glands, dorso-ventral caudal finfolds and absence of body pigmentation. On the basis of cercarial and adult morphology it is proposed that Pseudexorchis Yamaguti be excluded from the Cryptogonimidae.

Life cycle studies on two Digenea, Paradistomum geckonum (Dicrocoeliidae) and Mesocoelium sociale (Mesocoeliidae), in geckonid lizards from Indonesia

1987 ◽  
Vol 65 (10) ◽  
pp. 2491-2497 ◽  
Author(s):  
Murray J. Kennedy ◽  
L. M. Killick ◽  
M. Beverley-Burton
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Intermediate Hosts ◽  
Larval Stages ◽  
Hemidactylus Frenatus ◽  
Pulmonate Gastropod ◽  
First Intermediate Host

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.

Experimental studies on the transmission dynamics of the cercariae of Echinoparyphium recurvatum (Digenea: Echinostomatidae)

Parasitology ◽  
1983 ◽  
Vol 87 (1) ◽  
pp. 167-174 ◽  
Author(s):  
N. A. Evans ◽  
D. M. Gordon
Keyword(s):  
Life Span ◽  
Intermediate Host ◽  
Experimental Studies ◽  
Intermediate Hosts ◽  
Maximum Life Span ◽  
Age Dependent ◽  
Second Intermediate Host ◽  
The Mean ◽  
The Relationship ◽  
First Intermediate Host

SUMMARYAge-dependent survival and infectivity characteristics are described for the cercariae of Echinoparyphium recurvatum. At 18 °C the maximum life-span of the cercariae was 48 h and 50% survival occurred at 30·5 h. Infectivity of cercariae to the second intermediate host, Lymnaea peregra was maximal approximately 2 h after emission from the first intermediate host and it subsequently declined to zero at 19 h. It is suggested that the period of sub-maximal infectivity at the beginning of the cercarial life-span may represent a phase during which dispersal is an important function of the larvae. The relationship between infective stage density and establishment success was linear up to densities equivalent to 5000 cercariae/1. At higher cercarial densities the proportion of parasites establishing in second intermediate hosts declined progressively with increasing cercarial density. The mean number of parasites establishing/host increased linearly with increasing host size.

Temporal variation of Meiogymnophallus minutus infections in the first and second intermediate host

2010 ◽  
Vol 84 (4) ◽  
pp. 362-368 ◽  
Author(s):  
J. Fermer ◽  
S.C. Culloty ◽  
T.C. Kelly ◽  
R.M. O'Riordan
Keyword(s):  
Temporal Variation ◽  
Intermediate Host ◽  
Seasonal Patterns ◽  
Intertidal Flat ◽  
Infection Rates ◽  
Intermediate Hosts ◽  
Cerastoderma Edule ◽  
Scrobicularia Plana ◽  
Second Intermediate Host ◽  
First Intermediate Host

AbstractIn order to study seasonal patterns of Meiogymnophallus minutus infections in its intermediate hosts, bivalve samples were collected monthly between April 2008 and March 2009 from a high intertidal flat at Courtmacsherry Bay, Ireland. Infection rates in the first intermediate host Scrobicularia plana did not fluctuate significantly with season. Completely developed M. minutus cercariae appeared in daughter sporocysts from June and prevailed from July to October, indicating that transmission of M. minutus from its first to its second intermediate host is confined to this period of the year. All analysed individuals of the second intermediate host Cerastoderma edule were found to be infected with metacercariae. Infection levels significantly increased in September, suggesting recent cercarial invasions. Throughout the year, the majority of metacercariae were hyperinfected by the pathogenic microsporidian Unikaryon legeri. Spreading of hyperinfections was confined to spring and summer. Newly settled metacercariae were not affected by hyperparasitism and presumably retained their infectivity for half a year. Our findings suggest that the spreading of hyperinfections is correlated with higher water temperatures and that the entire metacercarial population has to rebuild every year as a consequence of hyperparasite-induced mortality.

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
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Experimental Infection ◽  
Definitive Host ◽  
Field Survey ◽  
Paratenic Host ◽  
Third Stage ◽  
Second Intermediate Host ◽  
First Intermediate Host

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.

THE MORPHOLOGY, TAXONOMY, AND LIFE HISTORY OF METORCHIS CONJUNCTUS (COBBOLD, 1860)

1944 ◽  
Vol 22d (1) ◽  
pp. 6-16 ◽  
Author(s):  
Thomas W. M. Cameron
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Intermediate Host ◽  
Larval Stages ◽  
History Of ◽  
Second Intermediate Host ◽  
The Common ◽  
First Intermediate Host

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.

The life-cycle of Bucephaloides gracilescens (Rudolphi, 1819) Hopkins, 1954 (Digenea: Gasterostomata)

Parasitology ◽  
1974 ◽  
Vol 68 (1) ◽  
pp. 1-12 ◽  
Author(s):  
R. A. Matthews
Keyword(s):  
Life Cycle ◽  
Intermediate Host ◽  
Host Specificity ◽  
Comparative Morphology ◽  
Rock Pools ◽  
Second Intermediate Host ◽  
High Degree ◽  
First Time ◽  
First Intermediate Host

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.

Digenean metacercariae (Timoniellaspp.,Labratrema minimusandCryptocotyle concava) from the flounder,platichthys flesus, in the tidal Thames

1999 ◽  
Vol 73 (2) ◽  
pp. 103-113 ◽  
Author(s):  
H.E.M. El-Darsh ◽  
P.J. Whitfield
Keyword(s):  
Intermediate Host ◽  
Detailed Examination ◽  
Nursery Ground ◽  
Intermediate Hosts ◽  
Thames Estuary ◽  
Platichthys Flesus ◽  
Second Intermediate Host ◽  
Temporal And Spatial Characteristics ◽  
First Time ◽  
First Intermediate Host

A detailed examination of the abundant flatfish speciesPlatichthys flesus, the flounder, in the tidal Thames has revealed the presence of four digenean metacercarial parasites,Cryptocotyle concava(Creplin, 1825),Timoniella imbutiforme(Molin, 1859),T. praeterita(Looss, 1901) andLabratrema minimus(Stossich, 1887). Flounders were recorded as a new second intermediate host forT. praeteritaandL. minimus. They were also recorded as second intermediate hosts for the first time in British waters forT. imbutiforme. The temporal and spatial characteristics of these infections were examined and were believed to provide indirect parasitological evidence of the movement patterns of flounders during their utilization of the Thames Estuary as a nursery ground. From these data it was also surmised that the first intermediate host ofT. imbutiforme,T. praeteritaandC. concavawas probably the molluscan speciesHydrobia ulvaein the lower Thames Estuary, whereasL. minimuswas most likely to occur in the molluscan hostCerastoderma edule, also present in the lower estuary.

scholarly journals Do three-spined sticklebacks avoid consuming copepods, the first intermediate host ofSchistocephalus solidus? — an experimental analysis of behavioural resistance

Parasitology ◽  
1996 ◽  
Vol 112 (4) ◽  
pp. 371-383 ◽  
Author(s):  
C. Wedekind ◽  
M. Milinski
Keyword(s):  
Intermediate Host ◽  
Gasterosteus Aculeatus ◽  
Alternative Prey ◽  
Intermediate Hosts ◽  
Predator Prey ◽  
High Prevalence ◽  
Behavioural Resistance ◽  
Prey Interaction ◽  
Second Intermediate Host ◽  
First Intermediate Host

SUMMARYMany parasites that use intermediate hosts are transmitted to the next host through predation. If the next host's fitness is strongly reduced by the parasite, it is under selection either to recognize and avoid infected intermediate hosts or to exclude that prey species from its diet when alternative prey are available. We investigated the predator-prey interaction between laboratory bred three-spined sticklebacks (Gasterosteus aculeatus), the second intermediate host of the cestodeSchistocephalus solidus, from 2 parasitized and 1 unparasitized population, and different prey types: infected and uninfected copepods and size-matchedDaphniaas alternative prey. Copepods with infective procercoids were more active, had a lower swimming ability and were easier to catch than uninfected controls. The sticklebacks preferred moving copepods. Therefore parasitized copepods were preferentially attacked and consumed. There was no effect of the sticklebacks' parent population being parasitized or not. The sticklebacks switched fromDaphniato (uninfected) copepods in the course of a hunting sequence; this switch occurred earlier in smaller fish. With this strategy the fish maximized their feeding rate:Daphniawere easier to catch than copepods but increasingly difficult to swallow when the stomach was filling up especially for smaller fish. However, there was no indication that sticklebacks from infected populations either consumedDaphniarather than copepods or switched later in the hunting sequence to consuming copepods than fish from an uninfected population. Thus, sticklebacks did not avoid parasitized prey althoughS. solidususually has a high prevalence and causes a strong fitness reduction in its stickleback host.

scholarly journals The Effect of Trematode Parasites on the Growth of Littorina Neritoides (L.)

1941 ◽  
Vol 25 (1) ◽  
pp. 69-80 ◽  
Author(s):  
Miriam Rothschild
Keyword(s):  
Intermediate Host ◽  
Large Size ◽  
Size Groups ◽  
Second Intermediate Host ◽  
Upward Slope ◽  
Accelerated Growth ◽  
The Difference ◽  
First Intermediate Host ◽  
Low Rate ◽  
Trematode Parasites

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.

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