Viruses in water. Standard method XP T90-451: 1996.
This test is performed according to French Standard XP T90-451: 1996 and used to detect viable virus in cell culture with the corresponding quantification of the virions present, and to detect viral genome by RT-PCR tests or PCR .
With this procedure the concentration of viruses present in the volume of water is desired (recommended minimum 20 liters), by adsorption to glass wool disposed in pressure filtration systems. Once filtered water volume, the virus filter glass can elute, concentrated by flocculation of bacteria and decontaminated by membrane filtration. The obtained virus suspension, is quantified by calculating the TCID50 performing seeding dilutions eluate in 12 replicates BGM cell culture for each dilution tested, calculating the number of virions present using the formula Spearman-Karber.
This can be quantified only virions causing a cytopathic effect on the cell monolayers used, as are most Enterovirus, but not all types and species can be detected by inoculation of cell culture. The type of virus found is identified by test PCR (polymerase chain reaction) followed by sequencing. Moreover, other viruses that do not cause cytopathic effect on the normal cell cultures (hepatitis A virus, hepatitis E virus, Norovirus, ......) by RT-PCR tests in the eluate can be detected adsorbed during the filtration.