One of the difficulties in measuring viral contamination in water is that viruses may be present at a very low concentration yet still make people ill. Even a single enteric virus can infect a human and cause gastroenteritis, and these viruses can survive for a long time in water.
Researchers from Tohoku University and Hokkaido University used activated sludge, produced during sewage treatment by aerating the sewage and allowing bacteria to breakdown organic material, as starting material in their search for a protein able to bind to enteric viruses. Using PCR the researchers isolated the gene coding for one of the subunits of GroEL from sludge DNA. GroEL is a 14 subunit 'chaperone' protein which ensures that proteins are folded correctly during their manufacture.
Using biochemical and enzymatic assays the subunit was found to be able to capture enteric viruses. GroEL is able to bind to hydrophobic amino acids on the surface of proteins and it is thought that the newly isolated EVBP similarly binds to hydrophobic areas on the surfaces of viruses and viral fragments.
Dr Daisuke Sano from Hokkaido University explained, "Unlike virus-specific and expensive antibodies, EVBP bound all the enteric viruses we tested (norovirus, rotavirus and poliovirus). Once developed this easy-to-use method could be used to detect low concentrations of viruses in the clinic or environment."