The influence of some physico-chemical factors on the host-finding capacity of Fasciola hepatica miracidia

1978 ◽  
Vol 52 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Niels Ørnbjerg Christensen ◽  
Peter Nansen ◽  
Flemming Frandsen
Keyword(s):  
Fasciola Hepatica ◽  
Host Finding ◽  
Salinity Level ◽  
Low Salinity ◽  
Physico Chemical ◽  
Lymnaea Truncatula ◽  
Turbidity Level ◽  
Chemical Factors ◽  
High Turbidity ◽  
Ph Range

ABSTRACTA study was made on the host-finding capacity of Fasciola hepatica miracidia in relation to time, number of miracidia per snail, and several physico-chemical environmental factors. Specimens of Lymnaea truncatula were exposed to radiolabelled miracidia and the subsequent snail-bound radioactivity was used to measure the host-finding capacity of the larvae.Maximum snail-bound radioactivity was achieved after 45–60 minutes exposure to miracidia in a volume of 80 ml water. The efficiency of the snail-location was unaltered up to a volume of 4.5 liters. A linear proportionality was demonstrated between the number of miracidia and the amount of radioactivity obtained in exposed snails. After 4 hours exposure snails placed in darkness took up the same amount of radioactivity as snails placed in bright illumination. Additional experiments showed that miracidia preferentially scan the lighted zone of a given environment, but if no snails are available in this zone, snails in shade are also effectively located.The host-finding capacity was unaltered up to a salinity level of 3.79%. At 4.74% and 5.68% the snail-location proceeded at a slower rate, but the final levels reached after 3 hours were comparable to that obtained at low salinity. The over-all host-finding capacity was reduced at a salinity level of 7.58% and at 9.47% the capacity had ceased. The host-finding capacity was unaltered in the pH range 5.4 to 8.4, but it was reduced at pH 8.9. Further studies showed that the host-finding capacity was clearly inhibited in water with a high turbidity level.

Interference with Fasciola hepatica snail finding by various aquatic organisms

Parasitology ◽  
1977 ◽  
Vol 74 (3) ◽  
pp. 285-290 ◽  
Author(s):  
Niels Ørnbjerg Christensen ◽  
Peter Nansen ◽  
Flemming Frandsen
Keyword(s):  
Fasciola Hepatica ◽  
Daphnia Pulex ◽  
Aquatic Organisms ◽  
Host Finding ◽  
Host Snail ◽  
Predatory Behaviour ◽  
Lymnaea Truncatula

Previous studies using radioactive miracidia have shown that a number of non-host snails and bivalves, interposed as ‘decoys’ in linear test channels, may interfere with the capacity of Fasciola hepatica miracidia to infect Lymnaea truncatula. Applying similar experimental principles, the role of several other potential interferents have been analysed in the present study. Daphnia pulex (Cladocera) and larvae of Corethra sp. (Diptera) exercised significant interfering effects by protecting ‘target’ snails from infection. Evidence suggested that this effect was a result of their normal predatory behaviour. Other organisms including Herpobdella testacea and Helobdella stagnalis (Hirudinea), Acellus aquaticus (Isopoda), Planaria lugubris (Turbellaria) and L. Truncatula egg clusters failed to interfere with miracidial host-finding. Nor did P. lugubris and L. truncatula ‘conditioned water’ interfere with the capacity of the miracidia to infect their host snail.

Molluscs interfering with the capacity of Fasciola hepatica miracidia to infect Lymnaea truncatula

Parasitology ◽  
1976 ◽  
Vol 73 (2) ◽  
pp. 161-167 ◽  
Author(s):  
Niels Ørnbjerg Christensen ◽  
Peter Nansen ◽  
Flemming Frandsen
Keyword(s):  
Infection Rate ◽  
Fasciola Hepatica ◽  
Host Finding ◽  
Decoy Effect ◽  
Bithynia Tentaculata ◽  
Lymnaea Truncatula

Fasciola hepatica miracidia labelled with radioselenium were used to study aspects of their host-finding capacity by determining radioactivity subsequently taken up by exposed ‘target’ snails (Lymnaea truncatula). Possible interfering effects exercised by a number of non-host snails and bivalves were examined in linear test channels. The infection rate (radioactivity) among ‘target’ snails was markedly lowered when non-host Lymnaea species (L. pereger, L. palustris, L. stagnalis) were interposed as ‘decoys’. The prosobranch Bithynia tentaculata and the bivalve Sphaeriwm corneum exhibited a slight decoy effect whereas pulmonate species like Anisus vortex, Gyraulus albus, Planorbis planorbis, Physa fontinalis did not interfere with miracidial host-finding.Other experiments showed that miracidia are more strongly attracted towards L. truncatula than L. pereger. Miracidia are not able to penetrate intact egg clusters of L. truncatula.

Decoy effect and host infection by miracidia within snail communities

Parasitology ◽  
1993 ◽  
Vol 106 (3) ◽  
pp. 265-276 ◽  
Author(s):  
N. H. Chipev
Keyword(s):  
Developmental Stages ◽  
Fasciola Hepatica ◽  
Host Finding ◽  
Specific Component ◽  
Host Snail ◽  
Decoy Effect ◽  
Individual Host ◽  
Lymnaea Truncatula ◽  
Host Infection ◽  
Distance Response

SUMMARYThe effect of experimental non-host snail (NHS) communities on the infection of Lymnaea truncatula with Paramphistomum daubneyi and Fasciola hepatica miracidia was studied. The results obtained indicated that NHS had variable effects on basic population parameters of host infection. Specifically, NHS were able to produce aggregation of sporocyst number/snail in the experimental host populations. Proposed hypotheses for decoy effect mechanisms failed to explain completely the experimental results. A new mechanism is suggested, based on a distance response of miracidia to snail chemo-attractants, to explain effects of NHS on miracidial host finding behaviour. It is assumed that miracidia have evolved the ability to discriminate among individual snail chemical attractants in a community already at a distance. This attribute of miracidial behaviour allows NHS to induce variations in the effectiveness of individual host localization by miracidia. The resulting aggregation of successful infections/host is assumed to be the specific component of snail decoy effect at the community level. It was also established that NHS affected trematode reproduction in the host inducing a compensatory increase in the intramolluscan population. Intraspecific competition among developmental stages is suggested to be the mechanism of this compensatory reaction.

scholarly journals Response of toxigenicVibrio cholerae01 to physico-chemical stresses in aquatic environments

1984 ◽  
Vol 93 (3) ◽  
pp. 475-495 ◽  
Author(s):  
Christopher J. Miller ◽  
Bohumil S. Drasar ◽  
Richard G. Feachem
Keyword(s):  
Stress Response ◽  
Strain Variation ◽  
Cation Composition ◽  
Optimal Salinity ◽  
Low Salinity ◽  
Physico Chemical ◽  
All Solutions ◽  
High Concentrations ◽  
Ph Range ◽  
Stressful Environments

SummaryThe survival and growth of toxigenicVibrio cholerae01 in water under various conditions of salinity, pH, temperature and cation composition and concentration were studied in an extensive series of laboratory experiments. Inter- and intra-strain variation in stress response (of 01 and non-01 strains) and the ability ofV. choleraeto adapt to stressful environments were also studied. ToxigenicV. cholerae01 were able to survive for at least 70 days at 25 °C in solutions of sea salt. The optimal salt concentration was 2·0% though all solutions in the range 0·25–3·0% gave good support. Substrains with enhanced capacity to persist at sub-optimal salinity (0·1%) were demonstrated. A great degree of inter-strain variation in stress response at low salinity (0·05%) was found among 59 strains, and this variation was unrelated to serogroup (01 or non-01), source (clinical or environmental) or country of origin (Tanzania or Bangladesh). At optimal salinity, inter-strain variation was less and 18 out of 20 strains remained viable at high concentrations for at least 40 months at 25 °C.V. cholerae01 could not survive beyond 45 days at 4 °C and optimal salinity, either with or without nutrients. The optimal pH range for survival at 25 °C was 7·0–8·5 at optimal salinity, and 7·5–9·0 at low salinity.V. cholerae01 require Na+for survival in the absence of nutrients, and for enhanced growth in their presence. The presence of Ca2+or Mg2+, in addition to Na+, further enhanced survival. These, and other results reported in this paper, suggest that toxigenicV. cholerae01 are able to survive for extended periods in warm water containing no nutrients but having a salinity of 0·25–3·0% and a pH of around 8·0. With added nutrients and under the same conditions, rapid growth is possible. The implications of these findings for the identification of putative aquatic reservoirs ofV. cholerae01, and for the epidemiology of cholera, are considerable.

SYSTEM PENDETEKSI KELAYAKAN KOLAM IKAN NILA MENGGUNAKAN METODE SAW (SIMPLE ADDITIVE WEIGHTING) BERBASIS IoT (INTERNET OF THINGS)

2021 ◽  
Vol 14 (1) ◽  
pp. 22-32
Author(s):  
Anderias Eko Wijaya ◽  
Aldi Riyadi
Keyword(s):  
Internet Of Things ◽  
Water Temperature ◽  
Body Shape ◽  
Fish Ponds ◽  
Weighting Method ◽  
Method Calculation ◽  
Turbidity Level ◽  
High Turbidity ◽  
Simple Additive Weighting ◽  
The Internet Of Things

Tilapia (Oreochromis niloticus) is a type of freshwater fish consumption with elongated and flattened body shape laterally and blackish white color. Tilapia originated from the Nile River and surrounding lakes. Now this fish has spread to countries on five continents with tropical and subtropical climates. Whereas in cold climates, tilapia cannot live well. ideal water temperature in tilapia enlargement ponds ranges between 27.7-29.3 ° C, where fish will grow optimally at water temperatures around 25-32 ° C.for the pH of the tilapia enlargement ponds range between 6, 4-8.5 and turbidity range of 3-19 NTU, because this high turbidity level has an effect on the amount of tilapia mortality. With the system that the researchers created, it was easier to determine a suitable fish pond to maintain as a life of tilapia with the help of the Internet of Things network system and reduce the failure rate in breeding and implementation of Thingspeak as a platform to display the results of data obtained by sensors and calculated with method calculation. This system takes data with temperature sensors, pH and Turbidity, to find water temperature, acidity and alkalinity in water and turbidity of water. Then the data obtained is sent to the ESP8266 module network and sent to the thingspeak platform, the data that appears is inputted into the database to be processed using the SAW method, the results of the SAW method calculation are displayed by the system. Implementation of the SAW (Simple Additive Weighting) Method for Detecting the Feasibility of Iot-Based Fish Ponds (Internet of Things) has been successfully implemented. So that it can rank tilapia ponds based on parameters of temperature, pH, turbidity.

scholarly journals Water Salinity Should Be Reduced for Irrigation to Minimize Its Risk of Increased Soil N2O Emissions

2018 ◽  
Vol 15 (10) ◽  
pp. 2114 ◽  
Author(s):  
Qi Wei ◽  
Junzeng Xu ◽  
Linxian Liao ◽  
Yawei Li ◽  
Haiyu Wang ◽  
...  
Keyword(s):  
Saline Water ◽  
N2o Emission ◽  
Salinity Level ◽  
N2o Emissions ◽  
Low Salinity ◽  
Nitrogen Inputs ◽  
Salinity Levels ◽  
N2o Fluxes ◽  
Moisture Dynamics ◽  
Irrigated Soils

To reveal the effect of irrigation salinity on soil nitrous oxide (N2O) emission, pot experiments were designed with three irrigation salinity levels (NaCl and CaCl2 of 1, 2.5 and 4 g/L equivalence, Ec = 3.6, 8.1 and 12.7 ds/m), either for 0 kg N/ha (N0) or 120 kg N/ha (N120) nitrogen inputs. N2O emissions from soils irrigated at different salinity levels varied in a similar pattern which was triggered by soil moisture dynamics. Yet, the magnitudes of pulse N2O fluxes were significantly varied, with the peak flux at 5 g/L irrigation salinity level being much higher than at 2 and 8 g/L. Compared to fresh water irrigated soils, cumulative N2O fluxes were reduced by 22.7% and 39.6% (N0), 29.1% and 39.2% (N120) for soils irrigated with 2 and 8 g/L saline water, while they were increased by 87.7% (N0) and 58.3% (N120) for soils irrigated with 5 g/L saline water. These results suggested that the effect degree of salinity on consumption and production of N2O might vary among irrigation salinity ranges. As such, desalinating brackish water to a low salinity level (such as 2 g/L) before it is used for irrigation might be helpful for solving water resources crises and mitigating soil N2O emissions.

scholarly journals Diurnal vertical migration of some cladocerans in relation to the physico-chemical factors in a fish pond

1970 ◽  
Vol 20 (2) ◽  
pp. 147-154 ◽  
Author(s):  
AS Bhuiyan ◽  
S Akhter ◽  
MMA Quddus
Keyword(s):  
Key Words ◽  
Vertical Migration ◽  
Fish Pond ◽  
Chemical Parameters ◽  
Surface Layers ◽  
Diurnal Vertical Migration ◽  
Physico Chemical ◽  
Chemical Factors ◽  
Diurnal Movement ◽  
The Relationship

Diurnal vertical migration of four genera of cladocerans, namely Diaphanosoma sp., Daphnia sp., Moina sp. and Bosmina sp., during March to December, 2007 showed that the number of Diaphanosoma sp. was 501 units/1 in the surface layers, 172 units/l in the middle layers and 190 units/l in the bottom layers. The yearly number of Daphnia sp. in surface, middle and bottom layerss was 362 units/l, 46 units/l and 189 units/l respectively. In surface, bottom and middle layers, the number of Moina sp. was 159, 71 and 32 units/l, respectively. Bosmina sp. was 78 units/l in surface, 31 units/l in the middle and 33 units/l in the bottom layers. The number of Diaphanosoma sp., Daphnia sp., Moina sp., Bosmina sp., were 455, 149, 259 and 358 units/l, respectively in the morning, 63, 176, 142, 43 units/l at noon and 107, 55, 28, 59 units/l, respectively in the evening. Throughout the study period the cladocerans were always abundant near the surface during morning and evening. Among the factors responsible for the diurnal movement of cadoceran, light played the most important factor. The relationship between the physico-chemical factors and the cladoceran occurrence in the pond was also explored. Key words: Cladocera; Diurnal migration; Physico-chemical parameters; Fish pond DOI: http://dx.doi.org/10.3329/dujbs.v20i2.8975 DUJBS 2011; 20(2): 147-154

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