RESUMO
Appropriate interpretation of a positive reverse transcription-PCR is an important issue for virus-related health hazard assessment because viral genomes and infectious viruses exhibit different behavior patterns in water. In this context, using Poliovirus 1 and Feline calicivirus f9 as examples of enteric viruses, first we demonstrated that the stability of infectious viruses is greatly affected by the temperature of mineral water (10, 20, and 35 degrees C) and that, in contrast, temperature has little effect on the corresponding genomes. Second, we demonstrated that infectious particles are degraded more rapidly than viral genomes at all temperatures studied. At 35 degrees C, Poliovirus 1 infectivity was reduced 4 logs after only 19 days, while an equivalent reduction would have taken 75 years (according to the model applied) for the viral genome. Contradictory conclusions can also be drawn concerning the sensitivity of viral serotypes depending on whether the infectious virus or the viral genome is considered. The Feline calicivirus f9 genome is more resistant than the Poliovirus 1 genome, whereas the opposite is true for the corresponding infectious viruses. Thus, we concluded that a positive test for a viral genome in mineral water must be interpreted with utmost caution because of the lack of a correlation between the presence of viral genomes and viral infectivity. Detection of viral genomes may be necessary to identify infectious risk for the human population, but it cannot be considered sufficient.
Assuntos
Genoma Viral , Águas Minerais/virologia , Vírus de RNA/isolamento & purificação , Vírus de RNA/patogenicidade , RNA Viral/metabolismo , Animais , Calicivirus Felino/genética , Calicivirus Felino/isolamento & purificação , Calicivirus Felino/patogenicidade , Gatos , Linhagem Celular , Criança , Efeito Citopatogênico Viral , Humanos , Vírus Norwalk/genética , Vírus Norwalk/isolamento & purificação , Poliovirus/genética , Poliovirus/isolamento & purificação , Poliovirus/patogenicidade , Vírus de RNA/genética , RNA Viral/genética , RNA Viral/isolamento & purificação , TemperaturaRESUMO
Some bacteriophages found in human faeces are being evaluated as possible indicators of viral contamination of water. These bacteriophages include somatic coliphages and Bacteroides fragilis phages. The aims of this study were to determine the occurrence and concentrations of somatic coliphages and Bacteroides fragilis phages in the stools of a human population residing in eastern France (n = 193). Somatic coliphages were detected in 68% of the stools at a mean concentration of 4.3 x 10(3) PFU.g-1 and Bacteroides fragilis phages were detected in 11% of the stools at a mean concentration of 7 x 10(1) PFU.g-1. Statistical analysis showed no correlation between the phage concentration and the age or sex of the human subject.
