Biomphalaria snails and larval trematodes , Biomphalaria snails and larval trematodes , کتابخانه مرکزی دانشگاه علوم پزشکی تهران

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Biomphalaria snails and larval trematodes

This chapter describes the methods used by the current authors and numerous other investigators to optimize conditions for successfully growing and maintaining both uninfected and infected Biomphalaria glabrata in the laboratory, with particular emphasis on the optimal physical, chemical, and biological factors that affect successful snail rearing and/or breeding, and the ways that they can be measured. Consideration is also given to incidental organisms that can alter aquarium ecology and affect both the snails and their intended trematode parasites. Various methods of infecting snails and maintaining snail tissues and cells in vitro are also described. The goal of this chapter is to aid researchers who have the need or desire to maintain the life cycle of this pulmonate and its trematode parasites in the laboratory.

Laboratory Rearing of Biomphalaria glabrata Snails and Maintenance of Larval Schistosomes In Vivo and In Vitro

Flame atomic absorption spectrometry was performed to determine the alteration of calcium concentration in the soft parts and shells of Biomphalaria alexandrina and Bulinus truncatus due to the infection with Schistosoma mansoni and S. haematobium, respectively. The results showed significant lowering in the calcium content of the shells of cercariae shedding B. alexandrina and B. truncatus relative to the calcium content in the shells of uninfected ones. In contrast, the calcium content in the soft parts of cercariae shedding snails was higher than in the soft parts of uninfected snails; the differences were statistically significant. Generally, calcium content was significantly higher in the shells than in the soft parts of the snails, regardless infected or uninfected. The results obtained and the hypothesis of hypercalcification in shells of infected snails were discussed.

Effects of Schistosoma mansoni and Schistosoma haematobium infections on calcium content in their intermediate hosts.

The forecasts of increasing global temperature and sea level rise have led to concern about the response of parasites to anthropogenic climate change. Whereas ecological studies of parasite response to environmental shifts are necessarily limited to short time scales, the fossil record can potentially provide a quantitative archive of long-term ecological responses to past climate transitions. Here, we document multi-centennial scale changes in prevalence of trematodes infesting the bivalve host Abra segmentum through multiple sea-level fluctuations preserved in brackish Holocene deposits of the Po Plain, Italy. Prevalence values were significantly elevated (p < 0.01) in samples associated with flooding surfaces, yet the temporal trends of parasite prevalence and host shell length, cannot be explained by Waltherian facies change, host availability, salinity, diversity, turnover, or community structure. The observed surges in parasite prevalence during past flooding events indicate that the ongoing global warming and sea-level rise will lead to significant intensification of trematode parasitism, suppressed fecundity of common benthic organisms, and negative impacts on marine ecosystems, ecosystem services, and, eventually, to human well-being.

Surges in trematode prevalence linked to centennial-scale flooding events in the Adriatic.

The aim of this chapter is to provide a clearer understanding of the complex relationship between Biomphalaria snails and larval schistosome parasites This chapter describes the numerous changes in host physiology, biochemistry, and behavior brought about by infection Specifically, the effects of larval schistosomes on host mortality, growth, metabolism, reproduction, organic and inorganic elements, and behavior are focused on The chapter concentrates on three Biomphalaria species; B glabrata, B alexandrina, and B pfeifferi and one species of schistosome, Schistosoma mansoni

Effects of Larval Schistosomes on Biomphalaria Snails

Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to study element ions in whole bodies of uninfected Biomphalaria glabrata snails and those experimentally infected with larval Schistosoma mansoni trematodes. Infected snails were analysed 8 weeks post-infection. Cohort snails that were left uninfected were analysed at the same time as the infected snails. Sixteen elements (aluminum, boron, barium, calcium, cadmium, copper, iron, potassium, magnesium, manganese, sodium, nickel, lead, selenium, tin and zinc) were found to be present in infected and uninfected whole bodies at concentrations above the detection limit of the ICP-AES analysis. Of these, calcium, cadmium, manganese and sodium were present in significantly higher amounts (Student's t-test, P < 0.05) in whole infected versus whole uninfected snails. Variations in the present results compared with other studies reflect intrinsic differences in the larval trematode-snail systems used.

G.L. Bosavage

Papers

Effects of Schistosoma mansoni infection on inorganic elements in the snail Biomphalaria glabrata