Author Fred Lewis
Introduction
Perhaps the most important component of rearing snails for any trematode life cycle is the quality of water that ensures growth and reproduction of the snails. Numerous water sources have been adopted by laboratories for rearing Biomphalaria spp. Water that is suitable for rearing Biomphalaria spp. is likely suitable for Bulinus and Oncomelania hupensis ssp. as well.
Recommendations
Among the water sources more frequently used is tap water that has been passed through an activated charcoal filter and “aged” a few days by bubbling air through the water column. This treatment usually reduces chlorine levels sufficiently to allow normal snail growth and reproduction. This water will commonly be referred to as “aged tap water” in many of the following SOPs.
Common alternatives to “aged tap water”
· Commercially available “spring” water (various sources). Spring water can be especially convenient for small life cycles where water requirements are not too large to make this an economically viable option.
· Chemically-defined solutions, such as the one described by Cohen et al (see below) can be attractive alternatives, especially in small-scale life cycles.
Whatever the source of water a laboratory uses, the water should be tested first to determine if it has an untoward effect on uninfected snails. Any negative effect(s) on the snails’ normal movement and feeding behavior will undoubtedly be noticed within a few hours or days.
References
Cohen, L. M., Neimark, H., and Eveland, L.K. 1980. Schistosoma mansoni: response of cercariae to a thermal gradient. Journal of Parasitology 66: 362-364.
Lewis, F.A., Stirewalt, M.A., Souza, C.P., and Gazzinelli, G. 1986. Large-scale laboratory maintenance of Schistosoma mansoni, with observations on three schistosome/snail host combinations. Journal of Parasitology 72: 813-829.
Tucker, M. S., Karunaratne, L. B., Lewis, F. A., Frietas, T. C., and Liang, Y-S. 2013. Schistosomiasis, in Current Protocols in Immunology 19.1.1-19.1.57, John Wiley and Sons, Inc., (R. Coico, Ed). Published online November 2013 in Wiley Online Library (wileyonlinelibrary.com). doi: 10.1002/0471142735.im1901s103.
