Biomphalaria alexandrina

About: Biomphalaria alexandrina is a research topic. Over the lifetime, 413 publications have been published within this topic receiving 3781 citations.

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.

Variation of transaminases and lactate dehydrogenase in irradiated Biomphalaria alexandrina snails.

Abstract: Effect of ultraviolet and gamma radiations on the activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LD) in Biomphalaria alexandrina snails, the specific intermediate host of schistosomiasis, was investigated. Changes in the electrophoretic pattern of LD in the species under study were also taken as a measured parameter and the effect of gamma-irradiation on the glutathione content in the haemolymph of the snails have been included.

Deteriorations in biological and biochemical aspects of biomphalaria alexandrina snails exposed to methanol extract of callistemon citrinus leaves

Abstract: Schistosomiasis is one of the deleterious parasitic diseases in many developing countries. One important approach to control the disease is to eliminate its intermediate hosts. Therefore, methanol extract from Callistemon citrinus leaves was evaluated against biological & biochemical aspects of Schistosoma mansoni infected and uninfected B. alexandrina snails,in addition to examination the histological changes in tissues of the snails’ digestive gland. The plant extract exhibited considerable molluscicidal potency against B. alexandrina snails. The egg-laying capacity and reproductive rate (R0) of S. mansoni infected and uninfected snails were suppressed post exposure to LC25 of methanol extract for 24h/week for 4 successive weeks. Reduction rate of R0 for snails infected only and those infected treated with LC25 were 65.8% and 70.9%, respectively. Infection rates of B. alexandrina snails with S. mansoni and cercarial production/infected snail were reduced as a reflection of their exposure to LC10 of the plant extract either pre-, during or post their exposure to miracidia. The total number of hemocytes of S. mansoni infected and uninfected snails was elevated post 24h of exposure to the plant extract. However, it was reduced after 4 weeks of successive exposure to the extract, but the large granulocytes were elevated. Also, exposure of B. alexandrina snails (infected and uninfected) to the plant extract caused deleterious morphological changes in their hemocytes. The activities of antioxidant enzymes LPO, CAT & SODwere elevated in tissue homogenate of uninfected snails after one week of exposure to the extract, while that of GSH was decreased. Moreover, the plant extract deteriorated the histological characters of digestive gland cells in treated snails ranged from degeneration and necrotic of its tubules, atrophy of different cell types and hyaline substance in enlarged digestive lumen..

Assessment of Infected Biomphalaria alexandrina Snails by Detecting Schistosoma mansoni Antigen and Specific Gene.

Abstract: To control spread of Schi s t o soma mansoni infection, rapid and accurate inves tigation of infected Biomphalaria alexandrina snails that surveyed from any suspected area is required. Routine assays for assessment of infected snails are time consumin g and may not be able to detect prepatent schis tosomal infections . In the present s tudy two methods were evaluate d for assessment of infected s n a ils . The firs t was detection of S. mansoni soluble egg antigens (SEA) in snail hemolymp h u s in g two murine monoclonal antibodies (MAbs) in sandwich ELISA assay. The S. mansoni antigens measured in the h e molymph of infected snails at intervals 1, 2, 3 weeks pos t exposure to miracidia, at early shedding snails (4,5) weeks a n d after the infected snails s topped shedding. Although the pos itivity, sens itivit y a n d specificity were 100% in the infected control group of snails , the detection of antigen (s ) was only poss ible after the second we a k o f miracidial infection. In the second method, genomic DNA of infected snails in addition to non infected (as negative control) we re s u b je c t e d to nes ted polymerase chain reaction PCR u s in g primers specific to S. mansoni fructose -1,6bis phosphate aldolase (SMALDO) g e n e . PCR was able to detect infection (100% sens itivity) at the 3rd day pos t infection. In spite of the superiority and the higher specificity of the immunodetection for larg scale detection of prepatency of B. alexandrina snails infected with S mansoni, the nes ted PCR assay revealed much higher sens itivity which enables 100% detection o f S . ma n soni infection down to 3 days pos t infection. So this assay provided higher efficiency for determin a t io n of infection prevalence in snails and schis tosomias is transmiss ion.