Multi-parasite host susceptibility and multi-host parasite infectivity: A new approach of the Biomphalaria glabrata/Schistosoma mansoni compatibility polymorphism

Abstract

In this study, we analyze the degree of susceptibility/un-susceptibility of five strains of Biomphalaria glabrata from different geographical origins successively challenged with a panel of 4 Schistosoma mansoni strains. A total of 20 homopatric and heteropatric host-parasite combinations were tested with exposure doses of 1, 10, 20, 30 and 50 miracidia per individual host. By doing this, we characterized each B. glabrata strain by its "multi-parasite susceptibility phenotype" that reflects better the efficiency of their defense mechanism against not only one, but a diversity of schistosome stocks. In the same time, all the S. mansoni strains used were characterized, by their "multi-host infectivity phenotype" that reflects the level of infectivity they display when confronted to diverse snail populations. Based on these results it is possible to select different homogenous stocks of snails with different spectrum of susceptibility/un-susceptibility for several parasite strains. This will be a useful tool for future functional studies conducted to understand the genetics and molecular basis of the compatibility polymorphism in this host/parasite model.

A multistrain approach to studying the mechanisms underlying compatibility in the interaction between Biomphalaria glabrata and Schistosoma mansoni

“…Three independent experiments were performed. The data presented in the present manuscript correspond to the mean values obtained in a previous published work [43] and the data obtained from two other experiments performed in 2010 and 2012.…”

“…Miracidia from the parasite strains ( Sm BRE, Sm LE, Sm GH2 and Sm VEN) were recovered from infected mouse livers and intestines and transformed into sporocysts in vitro as previously described [19]. Compatibility trials between the strains of parasites and snails were conducted as previously described [43]. For all sympatric and allopatric combinations, we experimentally infected snails with 20 miracidia per snail, which was previously shown to yield a maximum infection rate regardless of the utilized strain [43].…”

“…Compatibility trials between the strains of parasites and snails were conducted as previously described [43]. For all sympatric and allopatric combinations, we experimentally infected snails with 20 miracidia per snail, which was previously shown to yield a maximum infection rate regardless of the utilized strain [43]. Two weeks later, we assessed the prevalence (percentage of infected snails) and intensity (number of developed parasites per infected snail) of infection.…”

Universal Stress Proteins as New Targets for Environmental and Therapeutic Interventions of Schistosomiasis

“…Compatibility is heritable, either for the resistant or susceptible snail or in the parasite’s ability to infect an intermediate snail host. It may also be strain specific in that snails susceptible to a particular schistosome strain might not be so susceptible to another strain [43]. Theron and co-workers were able to show that among five B. glabrata and five S. mansoni strains, some snails had greater ability in recognizing parasites and producing ROS thus having a more efficient and effective defence system [43].…”

“…It may also be strain specific in that snails susceptible to a particular schistosome strain might not be so susceptible to another strain [43]. Theron and co-workers were able to show that among five B. glabrata and five S. mansoni strains, some snails had greater ability in recognizing parasites and producing ROS thus having a more efficient and effective defence system [43]. Other biotic factors directly or indirectly having an impact on these schistosomal stages include natural predators like invertebrates and fish which may reduce miracidia population by feeding on them [38].…”