Showing papers on "Biomphalaria alexandrina published in 2020"

Cystoseira barbata marine algae have a molluscicidal activity against Biomphalaria alexandrina snails supported by scanning electron microscopy, hematological and histopathological alterations, and larvicidal activity against the infective stages of Schistosoma mansoni

Abstract: Schistosomiasis is one of the neglected tropical diseases. Biomphalaria spp. is the intermediate host of Schistosoma mansoni. The aim of this study is to evaluate the molluscicidal activity of the ethanolic extract of Cystoseira barbata marine algae on Biomphalaria alexandrina snails. The present results indicated that HPLC of C. barbata ethanolic extract contained 20 flavonoids, 20 phenolic compounds and 10 saccharides. It has a molluscicidal activity on B. alexandrina snails at LC50 175.04 mg L− 1 after 48 h of exposure. Scanning electron microscope of the head foot region of B. alexandrina snails exposed to 2 LC50 (175.04 mg L− 1) of the ethanolic extract shows the rough surface and damaged cilia in the tentacles and the foot region; the mantle contained erosion in its tegmental surface. Exposure to LC50 of the ethanolic extract caused ovicidal, miracidicidal and cercaricidal effects. Examinations of the hemocytes monolayers of the exposed snails showed that hyalinocytes had a shrunken nucleus and granulocytes had irregular cell membrane, forming pseudopodia. Histopathological changes occurred in the head foot region after exposure to LC50 of the extracted algae, where, vacuoles, shrinkage in the mucous secreting glands and splitting of the oblique muscle fibers were present. Also, histopathological alterations occurred in the digestive gland where the digestive cells were ruptured, vacuolated and there was a marked increase in the number of the secretory cells and these alterations were concentration dependent. Conclusively, C. barbata ethanolic extract contains bioactive molecules that could be developed as molluscicides for the control of freshwater intermediate hosts for schistosomiasis.

Preliminary Phytochemical Screening, Total Phenolic Content, In Vitro Antioxidant and Molluscicidal Activities of the Methanolic Extract of Five Medicinal Plants on Biomphalaria Alexandrina Snails

Abstract: Schistosomiasis is a neglected tropical disease caused by blood flukes. Freshwater snails of genus Biomphalaria are the intermediate hosts of Schistosoma mansoni. The present study aimed to...

Semi-field and field trials to control Biomphalaria alexandrina and Bulinus truncatus, intermediate host snails of schistosomiasis in Egypt by the plant molluscicide Luowei/TDS 4%

Abstract: Controlling the snail intermediate hosts of schistosomiasis is an efficient and rapid method for reducing or eliminating the transmission of this disease. The present study aimed to assess the molluscicidal activity of Luowei/TDS 4% against Biomphalaria alexandrina and Bulinus truncatus under semi-field and field conditions in Egypt. Moreover, its effect on Schistosoma mansoni miracidial viability and infectivity to B. alexandrina snails and on cercarial production from infected snails were evaluated. In the present study, miracidia of Schistosoma mansoni and S. haematobium were exposed to sublethal concentrations of Luowi/TDS 4% and miracidial mortality rates in the test and control groups were recorded. The effect of exposure to LC10 and LC25 of Luowei/TDS 4% after 1, 2 and 3 weeks of B. alexandrina infection with miracidia on their cercarial production was determined. The molluscicidal activity of 2LC90Luowei/TDS 4% against B. alexandrina and B. truncatus was tested under semi-field and field conditions. Luowei/TDS 4% exhibited a promising molluscicidal potency against B. alexandrina and B. truncatus as their LC90 values were considerably low, 2.851 and 1.936 mg/L, respectively, after 24 h of exposure. Moreover, infection rates of B. alexandrina with S. mansoni and cercarial production from snails exposed to LC10 and LC25 of Luowei/TDS 4% post miracidial exposure were reduced. Moreover, Luowei/TDS 4% at semi-field and field trials proved to be a potent molluscicidal agent against schistosomiasis intermediate host snails as mortality rates of free and caged sentinel snails from these trials were considerably high ranging from 87% to 100% after 24 h of treatment with 5.702 mg/L (2LC90 for B. alexandrina snails). Luowei/TDS 4% should be considered as a candidate molluscicide in schistosomiasis control programs. Implementation of this plant molluscicide in operational schistosomiasis control strategies will minimize the ecological side-effects associated with replacing synesthetic chemicals.

Morphology and kinetics of susceptible and resistant Biomphalaria alexandrina hemocytes during the first week of exposure to Schistosoma mansoni miracidia

Abstract: Background: Few studies concerning Biomphalaria alexandrina (B. alexandrina) snail hemocytes’subpopulations, and their relation to the compatibility with Schistosoma mansoni (S. mansoni)’ miracidiawere performed. Manipulation of parasite development inside these snails could be applied as a controlmeasure against schistosomiasis.Objectives: Knowing that the snail hemocytes temporarily bind to the parasites, allowing the developmentof cercariae that are infective to the definitive host. This study aimed at studying the morphology andkinetics of diverse hemocytes of susceptible and resistant B. alexandrina and their participation in thesnail early immune response after challenge by S. mansoni.Material and Methods: Giemsa stained hemocytes were characterized using light microscopy. Total anddifferential hemocyte counts (THC and DHC) were calculated in the hemolymph of two groups composedof 60 susceptible and 60 resistant snails. Each group was further subdivided as 12 control pre-exposuresnails (PE) and 48 post-exposure snails (PO) to S. mansoni at different time points (6 h, 1, 3 and 7 days).THC and DHC counts were recorded by a snail hemogram.Results: Results revealed that granulocytes constituted the most common population all through theexperiment with the large dense-granulated granulocytes subpopulation being the largest-sized cellsdetected. The highly reactive subpopulations that increased in number upon exposure to S. mansoni werethe few-granulated and the large-granulated granulocytes, suggesting their possible participation in earlyparasite destruction.Conclusion: The resulting hemograms helped determine the participation of hemocyte populations andsubpopulations in the defense against S. mansoni, aiding in understanding snail compatibility patterns.Further studies to propagate transgenic B. alexandrina snails abundant in large granular granulocytesutilizing (gene editing) CRISPR-Cas9 technique are recommended. This would be required to spreadschistosome resistance traits in snail populations, thus, contributing to reduced schistosomiasistransmission in the long run.

Evaluation of Fentonʼs Reagent Toxicity to Biomphalaria Alexandrina Snails

Abstract: Fentonʼs reagent is considered a promising disinfecting agent as it has antimicrobial activity. In the present study, effective antifungal Fenton concentrations were investigated on Biomphalaria alexandrina snails as bio indicators of toxicity. Generally, they resulted in low mortality rate of snails, as only 20% mortality was recorded after 60 min of exposure. Also the activities of two antioxidant enzymes; catalase (CAT) and superoxide dismutase (SOD) in snails’ tissues were investigated at different time intervals. Although the activities of both enzymes were different from control group, there was not a pronounced enhancement or inhibition. In conclusion, certain Fenton concentrations can be used as inexpensive and environmentallyfriendly disinfecting agents as they are safe on snails which are good bioindicators of toxicity.

Effect of some medicinal plant extracts as molluscicidal and apoptotic agents on Biomphalaria alexandrina snails

Abstract: ARTICLE INFO Article History: Received: March 8, 2020 Accepted: March 30, 2020 Online: April 3, 2020 _______________

Resistance of Biomphalaria alexandrina to Schistosoma mansoni and Bulinus truncatus to Schistosoma haematobium Correlates with Unsaturated Fatty Acid Levels in the Snail Soft Tissue.

Abstract: Only a fraction of the Biomphalaria and Bulinus snail community shows patent infection with schistosomes despite continuous exposure to the parasite, indicating that a substantial proportion of snails may resist infection. Accordingly, exterminating the schistosome intermediate snail hosts in transmission foci in habitats that may extend to kilometres is cost-prohibitive and damaging to the ecological equilibrium and quality of water and may be superfluous. It may be more cost effective with risk less ecological damage to focus on discovering the parameters governing snail susceptibility and resistance to schistosome infection. Therefore, laboratory bred Biomphalaria alexandrina and Bulinus truncatus snails were exposed to miracidia of laboratory-maintained Schistosoma mansoni and S. haematobium, respectively. Snails were examined for presence or lack of infection association with soft tissue and hemolymph content of proteins, cholesterol, and triglycerides, evaluated using standard biochemical techniques and palmitic, oleic, linoleic, and arachidonic acid, assayed by ultraperformance liquid chromatography-tandem mass spectrometry. Successful schistosome infection of B. alexandrina and B. truncatus consistently and reproducibly correlated with snails showing highly significant (up to P < 0.0001) decrease in soft tissue and hemolymph content of the monounsaturated fatty acid, oleic acid, and the polyunsaturated fatty acids, linoleic, and arachidonic acids as compared to naive snails. Snails that resisted twice infection had soft tissue content of oleic, linoleic, and arachidonic acid similar to naive counterparts. High levels of soft tissue and hemolymph oleic, linoleic, and arachidonic acid content appear to interfere with schistosome development in snails. Diet manipulation directed to eliciting excessive increase of polyunsaturated fatty acids in snails may protect them from infection and interrupt disease transmission in a simple and effective manner.

Efficiency of Three Extracts of Carica papaya as Molluscicidal and Anti-schistosomal Agents against Biomphalaria alexandrina and Schistosoma mansoni by Flow Cytometry

Abstract: Schistosomias is a prevalent parasitic disease in tropical and sub-tropical areas, which comes in the second place in terms of socioeconomic and public health burden. Around 600 million people in 74 countries are infected yearly, predominantly in the developing world. The aim of this work was to assess the efficiency of three extracts from Carica papaya (methanol, ethanol and butanol extracts) for their molluscicidal and anti-schistosomal activities. The LC50 of methanol, ethanol and butanol extracts of Carica papaya against B. alexandrinea were 180, 499.3 and 509.1 mg/L while the respective LC90 values were 220.3, 700.6, 769.6 mg/L respectively. The effect of these extracts on Biomphalaria alexandrina snails and larval stages of Schistosma mansoni, for miracidia the LC50 of methanol, ethanol and butanol extracts of Carica papaya against miracidia were 3.4, 15.4 and 8.1 mg/L, respectively, while the respective LC90 values were 8.4, 38.2, 11.2 mg/L, and for cercariae the LC50 of methanol, ethanol and butanol extracts of Carica papaya were 2, 20 and 4 mg/L, while the respective LC90 values were 13.5, 80.5, 18.5 mg/L respectively was evaluated, in addition to flowcytometric analysis of CD4, CD25, FOXP3 and TGF-β levels during S. mansoni infection in mice. The in-vivo results showed that the three extracts have variable potential against snails and miracidia and cercariae of S. mansoni. The mortality rate in B. alexandrina snails for methanol, ethanol and butanol extracts of Carcia papay were 86%, 45% and 64%, respectively. While it was 83%, 35% and 66%, respectively in miracidia and 92%, 40% and 70%, respectively in cercariae. The results indicated that methanol extract from Carica papaya recorded higher activity against snails, miracidia and cercariae. The levels of CD4, CD25, FOXP3 regulatory T (Treg) cells were decreased significantly (p<0.001) in infected mice compared to healthy controls. However, there was a significant (p<0.001) increase in levels of TGF-β. A significant increase in the levels of CD4, CD25, and FOXP3 Treg in Carica papaya treated group compared to infected control group, with a significant (p<0.001) decrease in TGF-β level than infected group. In conclusion, methanol extract was more effective at concentration of LC50 180 and LC90 220.3 than ethanol and butanol extracts of Carica papaya therefore controlling B. alexandrina snails by methanol extract is a promising way as it is an eco-friendly strategy in rural areas of developing countries, where schistosomiasis is endemic. Moreover, the increased immune defense mechanism in treated group with the same extracts is a promising target for new immune modulatory strategies against schistosomiasis.

Efficacy of Miltefosine and Artemether on Infected Biomphalaria Alexandrina Snails with Schistosoma Mansoni: Immunological and Histological Studies.

Abstract: Biomphalaria alexandrina snails have received much attention due to their great medical importance as vectors for transmitting Schistosoma mansoni infection to humans. The main objective of the present work was to assess the efficacy of miltefosin a synthetic molluscicidal drug and artemether a natural molluscicidal drug. The correlation between immunological and histological observations from light and electron microscopy of the hemocytes of B. alexandrina post treatment with both drugs was also evaluated. LC50 and LC90 values were represented by 13.80 ppm and 24.40 ppm for miltefosine and 16.88 ppm and 27.97 ppm for artemether, respectively. The results showed that the treatment of S. mansoni-infected snails and normal snails with sublethal dose of miltefosine (LC25=8.20 ppm) and artemether (LC25=11.04 ppm) induced morphological abnormalities and a significant reduction in hemocytes count.

Assessment of metallothionein expression in Biomphalaria alexandrina snails and Oreochromis niloticus Fish as a biomarker for water pollution with heavy metals.

Abstract: Heavy metals are natural elements present in the environment (Wegwu et al., 2010). They are usually present in trace amounts in natural waters but many of them are toxic even at very low concentrations (Herawati et al., 2000). The accumulation of metals in an aquatic environment has a direct impact on the sustainability of the ecosystem. The bioavailability of any particular metal in the aquatic organisms or fish that are being ARTICLE INFO ABSTRACT Article History: Received: March 1, 2020 Accepted: March28, 2020 Online: April 1, 2020 _______________

Reproductive and developmental alterations in Biomphalaria alexandrina snails exposed to three phenolic compounds

Abstract: The present work aims to assess the reprotoxicity in Biomphalaria alexandrina snails and developmental and hatchability alterations of their eggs after exposure to three phenolic compounds, viz., s...