An improved method for concentrating rotavirus from water samples

A modified adsorption-elution method for the concentration of seeded rotavi rus from water samples was used to determine various factors which affected the virus recovery. An enzyme-linked immunosorbent assay was used to detec t the rotavirus antigen after concentration. Of the various eluents compare d, 0.05M glycine, pH 11.5 gave the highest rotavirus antigen recovery using negatively charged membrane filtration whereas 2.9% tryptose phosphate bro th containing 6% glycine; pH 9.0 was found to give the greatest elution eff iciency when a positively charged membrane was used. Reconcentration of wat er samples by a speedVac concentrator showed significantly higher rotavirus recovery than polyethylene glycol precipitation through both negatively an d positively charged filters (p-value <0.001). In addition, speedVac concen tration using negatively charged filtration resulted in greater rotavirus r ecovery than that using positively charged filtration (p-value = 0.004). Th irty eight environmental water samples were collected from river, domestic sewage, canals receiving raw sewage drains, and tap water collected in cont ainers for domestic use, all from congested areas of Bangkok. In addition, several samples of commercial drinking water were analyzed. All samples wer e concentrated and examined for rotavirus antigen. Coliforms and fecal coli forms (0->1,800 MPN/100 ml) were observed but rotavirus was not detected in any sample. This study suggests that the speedVac reconcentration method g ives the most efficient rotavirus recovery from water samples.