scholarly journals Copper toxicity to the endoparasitic trematode (Posthodiplostomum minimum) relative to physid snail and bluegill sunfish intermediate hosts

1998 ◽  
Vol 17 (12) ◽  
pp. 2512-2516 ◽  
Author(s):  
David J. Soucek ◽  
Gayle P. Noblet
Keyword(s):  
Copper Toxicity ◽  
Bluegill Sunfish ◽  
Intermediate Hosts ◽  
Posthodiplostomum Minimum

Fine Structure of Posthodiplostomum Minimum Metacercarial Cyst Wall

1973 ◽  
Vol 31 ◽  
pp. 490-491
Author(s):  
C. W. Mitchell
Keyword(s):  
Cyst Wall ◽  
Outer Wall ◽  
Digenetic Trematode ◽  
Ultrastructural Organization ◽  
Fresh Water Fish ◽  
Intermediate Hosts ◽  
Metacercarial Cyst ◽  
Posthodiplostomum Minimum ◽  
Water Fish ◽  
Host Origin

The metacercaria of the digenetic trematode Posthodiplostomum minimum inhabit the major visceral organs, e.g. liver, kidney or heart, of numerous species of fresh-water fish as second intermediate hosts. These larval trematodes establish a thin cyst wall which is composed of a cellular, outer wall of host origin and an inner, acellular layer of parasitic origin. This report describes some preliminary observations on the ultrastructural organization of the metacercarial cyst wall found within naturally infected sunfish liver.These observations represent the first strigeid cyst studied by electron microscopy. However, cyst structure resembled others encysted within tissues of an intermediate host. A primary wall, apparently secreted by the parasite, prevents host destruction of the metacercaria.

Effect of copper and zinc upon the survival and infectivity of Echinoparyphium recurvatum cercariae

Parasitology ◽  
1982 ◽  
Vol 85 (2) ◽  
pp. 295-303 ◽  
Author(s):  
N. A. Evans
Keyword(s):  
Copper Toxicity ◽  
Water Hardness ◽  
Hard Water ◽  
Parasite Transmission ◽  
Intermediate Hosts ◽  
Profound Influence ◽  
Copper And Zinc ◽  
Freshwater Habitats ◽  
Lower Effect ◽  
Effect Of Copper

SUMMARYAt concentrations ranging from 0·1 to 10·0 mg/l, copper and zinc reduced both the longevity and infectivity of Echinoparyphium recurvatum cercariae. Concentrations of 10·0 mg/l copper and zinc in hard water reduced the time to 50% mortality of cercariae from 30·5 h to 8·5 h and 15·5 h respectively. Copper-induced effects upon cercarial infectivity were particularly severe and exposures of cercariae to 0·5 mg/l of this metal for as little as 15 min caused significant reductions in their ability to infect molluscan 2nd intermediate hosts. Water hardness had a marked influence on copper toxicity but had a much lower effect on the toxicity of zinc. Metal concentrations found to exert a profound influence on parasite transmission in the present laboratory-based study have been found to occur in natural, albeit polluted, freshwater habitats.

Phylogeny and morphology of Ovipleistophora diplostomuri n. sp. (Microsporidia) with a unique dual-host tropism for bluegill sunfish and the digenean parasite Posthodiplostomum minimum (Strigeatida)

Parasitology ◽  
2017 ◽  
Vol 144 (14) ◽  
pp. 1898-1911 ◽  
Author(s):  
J. LOVY ◽  
S. E. FRIEND
Keyword(s):  
Lepomis Macrochirus ◽  
Aquatic Organisms ◽  
Fish Tissue ◽  
Surface Coat ◽  
Bluegill Sunfish ◽  
Microsporidian Parasite ◽  
Host Tropism ◽  
Posthodiplostomum Minimum ◽  
Close Relationship ◽  
Relationship Of

SUMMARYMicrosporidia are diverse opportunistic parasites abundant in aquatic organisms with some species hyperparasitic in digenean parasites. In the current study, we describe a unique microsporidian parasite, Ovipleistophora diplostomuri n. sp. that has a tropism for both the bluegill sunfish Lepomis macrochirus, and its digenean parasite Posthodiplostomum minimum. Though the microsporidium first infects a fish, the subsequent infection causes hypertrophy of the metacercarial wall and degeneration of the P. minimum metacercariae within the fish tissue. Genetic analysis placed this species within Ovipleistophora and ultrastructural characteristics were consistent with the genus, including the presence of dimorphic spores within sporophorous vesicles. Meronts did not have a surface coat of dense material, which has been previously reported for the genus. This is the first Ovipleistophora species described that does not have a tropism for ovary. Genetics demonstrated that O. diplostomuri n. sp. groups closely within fish microsporidia and not other species known to be hyperparasitic in digeneans, suggesting that it evolved from fish-infecting microsporidians and developed a secondary tropism for a common and widespread digenean parasite. The high genetic identity to Ovipleistophora species demonstrates the close relationship of this unique microsporidian with other microsporidia that infect ovary.

Ultrastructure of Cercarial Tails

1974 ◽  
Vol 32 ◽  
pp. 180-181
Author(s):  
Richard S. Demaree ◽  
Donald M. Wootton
Keyword(s):  
Schistosoma Japonicum ◽  
Intermediate Hosts ◽  
Suitable Host ◽  
Ultrastructural Studies ◽  
Tail Structure

Cercariae (juvenile trematodes with tails) emerge from mollusk intermediate hosts and swim toward definitive hosts or encystment objects. The locomotor power is furnished by the tail. Upon reaching a suitable host or encystment object, the tail is cast off and the cercariae penetrate and/or encyst. Ultrastructural studies of cercariae are sparse. There is even lessUltrastructural studies of cercariae are sparse. There is even less information about the tail structure; and body-to-tail morphology has been documented only for Acanthatrium oregonense and Schistosoma japonicum.

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