Chemoattraction and penetration of Echinostoma trivolvis and E. caproni cercariae in the presence of Biomphalaria glabrata , Helisoma trivolvis , and Lymnaea elodes dialysate

1997 ◽  
Vol 83 (2) ◽  
pp. 193-197 ◽  
Author(s):  
B. Fried ◽  
Betsy A. Frazer ◽  
Aditya Reddy
Keyword(s):  
Biomphalaria Glabrata ◽  
Helisoma Trivolvis ◽  
Lymnaea Elodes ◽  
Echinostoma Trivolvis

Evidence from two planorbid snails of a complex and dedicated response to digenean (echinostome) infection

Parasitology ◽  
1999 ◽  
Vol 119 (4) ◽  
pp. 395-404 ◽  
Author(s):  
C. M. ADEMA ◽  
L. A. HERTEL ◽  
E. S. LOKER
Keyword(s):  
Staphylococcus Epidermidis ◽  
Biomphalaria Glabrata ◽  
The Other ◽  
Digenetic Trematode ◽  
Snail Species ◽  
Helisoma Trivolvis ◽  
General Ability ◽  
Digenean Species ◽  
Reactive Plasma ◽  
Echinostoma Trivolvis

The planorbid snail Biomphalaria glabrata responded to exposure to either the compatible digenetic trematode Echinostoma paraensei or the incompatible species Echinostoma trivolvis by producing increased amounts of several distinctive plasma polypeptides. These polypeptides characteristically precipitated from plasma when mixed with secreted–excreted products (SEP) of sporocysts or rediae from either digenean species. In contrast, control snails, or snails that had been wounded or infected with bacteria (Serratia marcesens or Staphylococcus epidermidis) showed no obvious plasma alterations and no precipitates formed when their plasma was mixed with SEP. Another planorbid species, Helisoma trivolvis, which displays reverse compatibility for the echinostome species used, also responded to exposure to both echinostomes by increased production of plasma polypeptides that precipitated in the presence of SEP. With some individual variation, these 2 snail species synthesized SEP-reactive plasma polypeptides forming diffuse bands centred at 53, 65, 80–120 and 200 kDa (the latter absent in Helisoma trivolvis). The 53 kDa polypeptides had not been observed before, whereas the others have been noted from B. glabrata. The diffuse 65 kDa band was strongly bound by anti-fibrinogen antibodies, supportive of earlier studies indicating it contains fibrinogen-related domains. The other specified polypeptides were also bound by these antibodies raising the possibility that they too contain fibrinogen domains. The results are suggestive of a general ability of these 2 planorbid snails to detect the presence of echinostomes even if the latter are subsequently incapable of development. The complex response they then mount, one not evoked by other challenges such as wounding or bacterial infection, may represent a dedicated response to a frequently encountered group of pathogenic parasites, the digeneans (echinostomes).

Maintenance of Helisoma trivolvis naturally infected with Echinostoma trivolvis in spring water at 4°C for 300 days

1998 ◽  
Vol 72 (1) ◽  
pp. 91-92 ◽  
Author(s):  
K.A. Schmidt ◽  
B. Fried ◽  
A. Reddy
Keyword(s):  
Snail Host ◽  
Spring Water ◽  
Helisoma Trivolvis ◽  
Intermediate Snail Host ◽  
Significant Difference ◽  
Parasite Survival ◽  
The Mean ◽  
Echinostoma Trivolvis ◽  
Cercarial Emergence

AbstractHelisoma trivolvis (Pennsylvania strain) snails naturally infected with Echinostoma trivolvis larvae were maintained for 10 months (300 days) at 4°C in artificial spring water to determine the effects of storage on parasite survival. Three of 20 snails were alive at 10 months and when isolated in spring water at 22−24°C released active cercariae. The mean number of cercariae released in 2 h from each stored snail was significantly less than that from freshly collected snails. Infectivity of cercariae from stored hosts to experimentally infected, laboratory-raised Helisoma trivolvis (Colorado strain) snails was significantly less than that of cercariae from fresh hosts based on cyst recoveries in the Colorado strain of H. trivolvis within 24 h p.i. There was no significant difference in the redial number or the number of cercariae per redia in stored versus fresh snails. In conclusion, some reduction in cercarial emergence and decrease in cercarial infectivity to a second intermediate snail host occurred following storage of H. trivolvis naturally infected with E. trivolvis in ASW at 4°C for 10 months.

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