Concentration of viruses from water in alginate membranes and the mussel Dreissena polymorpha.

Human enteric viruses are normally present in natural waters in low numbers and therefore sensitive techniques are required for their isolation. In this study two techniques were investigated, one quantitative, alginate ultrafiltration, and the other qualitative, the mussel Dreissena polymorpha. In the first part of the study the alginate technique was investigated in the laboratory and in the field. In the laboratory the influence of parameters affecting the efficiency of the membrane for concentrating virus was investigated as well as factors which influenced the recovery of virus from the membrane. The alginate method was found to be reasonably reproducible over a wide range of parameters such as temperature, initial virus concentration and type of enterovirus but was sensitive to pH above pH8 and an optimum volume of sodium citrate was critical for maximum recovery of the virus. A significant amount of the virus was never recovered and attempts to trace this failed. The application of alginate filtration to the recovery of virus from samples of sewage effluent and river water indicated that the method was very sensitive as it was possible to detect less than 1PFU/L. In the second part of the study the mussel D. polymorpha was tested for its capacity to concentrate viruses in the laboratory and in the field. Factors which influenced the concentration efficiency included temperature and the type of turbidity (organic or inorganic) present in the water. In the majority of experiments the mussel concentrated the virus to a level ten times that in the water but unfortunately this was insufficient for the detection of virus in the natural samples of river water. Both concentration techniques were discussed in relation to each other, to other concentration techniques and to the type of water from which viruses are to be isolated