Effect of the pesticides carbofuran [Carbamate] and Profenophos [Organophosphorus] on Biomphalaria alexandrina and on its infection with Schistosoma mansoni miracidia

Carbofuran [carbamate pesticide] and Profenophos [organophosphorus pesticide] showed molluscicidal effect on Biomphalaria alexandrina snails, with the LC[50] 1.42 ppm and 1.29 ppm, respectively Maintaining Biomphalaria alexandrina at sublethal concentrations of these compounds [0.5, 0.75, and 1.0 ppm] reduced the snail survival rate and net reproductive rate [R[0]] [E L[x]M[x]] compared with the control snail group. The percentage reduction in R[0] was 86.9, 90.8, and 93.9 for the tested concentrations of Carbofuran and 86.8, 82.9 and 88.5 for the tested concentrations of Profenophos, respectively. The susceptibility of Biomphalaria snails to infection with Schistosoma mansoni miracidia and further infectivity of this parasite were also reduced. Increasing the pesticide concentration increased the magnitude of reduction reaching 80.7% and 89.3% for the two pesticides, respectively. Pesticide may be considered one of the factors contributing in the disappearance of snail vectors on reaching water bodies as residues from pesticidal activities and consequently hindering schistosomiasis transmission

Effects of double infection with Echinostoma liei and Schistosoma mansoni on hemoglobin content and circulating hemocytes in the hemolymph of the host snail Biomphalaria Alexandria

Three groups of hemocyte cells were identified in the hemolymph of B. alexandrina snails. These are granulocytes, hyalinocytes and undifferentiated [round] cells. Granulocytes are most common. Exposure of B. alexandrina to S. mansoni and E. Liei miracidia significantly increased the number of circulating hemocytes in one-week post miracidial exposure. Meanwhile, the increase in cell number counted at two and three weeks post exposure was not statistically significant. The percentage of hemocyte categories were changed in the exposed groups of snails one week and two-weeks post exposure. In one week post exposure group, snails had significantly higher percentages of undifferentiated cells than controls. While, in two weeks post miracidial exposure group, the percentage of granulocytes significantly increased. Infection of B. alexandrina with S. mansoni and E. liei significantly reduced the hemoglobin content in their hemolymph during first-, second and third weeks post miracidial exposure

Effect of infection with fasciola gigantica on protein, lipid contact and some enzymes of the intermediate host snail lymneae natalensis

Total protein and lipid contents were estimated in hemolymph of Lymnaea natalensis snails infected with Fasciola gigantica. There was significant reduction in total protein content, while the lipid content in infected snails showed a significant elevation. Also, there was a significant increase in the activity of hexokinase [HK] by 48.9% and glucose phosphate isomerase [GPI] by 40% and a decrease in lactate dehydrogenase [LDH] by 53.7% in infected snails when compared to control snail group