Biomphalaria alexandrina

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

Effect of biomphalaria alexandrina snails infected by bacillus thuringiensis kurstaki on three successive generations of schistosoma mansoni

Abstract: The effect of infection of Biomphalaria alexandrina snails with Bacillus thurin-giensis kurstaki on various stages of Schistosoma mansoni life cycle was studied for three successive generations. Thus, two groups of snails were exposed to a sublethal concentration of the bacteria (0.08 gm/L water) containing 32000 IU/mg, for one week and to schistosome miracidia. One group was exposed to the miracidia before bacterial infection, while the other group to the miracidia after the bacterial infec-tion. Cercariae produced from each group of snails were used to infect albino mice. The infection of snails and mice with the parasite was repeated for three generations of the parasite. In the first case, data obtained show that the schistosome infection rate of snails was considerably reduced being 60%, 18%, and 66.6% versus 90 % , 92% and 90% in untreated control snails in the three generations of the parasite, re-spectively. Meanwhile, the mean prepatent period was extended being 29.1  4.3 days, 33  1 days and 38.5  2.5 days versus 27 days in the control group. The num-ber of worms recovered from infected mice showed reduction of 52 %, 78.4% and 58.6%, respectively. In the second case, the infection rate of snails was 40%, 16% and 73.7% for the three successive parasite generations and the prepatent period was 32  1 days, 32  2.3 days and 35  2.8 days, respectively. The reduction percentage of the recovered worms was 34.8, 73.6 and 72.9 in the sccessive generations, respec-tively. The present results prove that infecting B.alexandrina snails with a sublethal concentration of B. thuringiensis kurstaki bacteria exhibits clear negative effect on the transmission of S. mansoni in three successive generations. So, it could be rec-ommended to use B. thuringiensis kurstaki as a potential biocontrol agent against S. mansoni.

Immune response of stimulated biomphalaria alexandrina snails with schistosoma mansoni infection.

Abstract: In this study, both digestive and hermaphrodite glands in Biomphalaria alexandrina snails were examined by light microscope (LM) and scanning electron microscopy (SEM) in a trial to clarify its immunological role as defense mechanism against the parasite infection. B. alexandrina snails used were exposed individually to Schistosoma mansoni miracidia; according to their responsq they were classified into infected snails (shed cercariae) and non-infected snails (failed to shed cercariae). Snails not exposed to S. mansoni miracidia used as control. LM showing great histological alteration in tissues, of the both glands in infected snails, these changes represented by degenerated both oocyte and spermatocyte in hermaphrodite gland in addition to degenerated digestive gland while non-infected snails showing mild degenerated ova with normal spermatocytes also degenerated miracidia. inside granuloma like structure with concentric layers of fibroblast and haemocyte could be observed. By SEM we could detect extensively damaged and fibrosed non-motile cilia with exfoliation of tegumental surface in in- fected B.alexandrina while non-infected ones showing attached numerous cilia with some ballooning of the folds.