R Gabrieli

Depuration of Mytilus galloprovincialis experimentally contaminated with hepatitis A virus

Mussels (Mytilus galloprovincialis) were contaminated with known amounts of laboratory strains of hepatitis A virus and Poliovirus 1 and the effectiveness of a self-cleansing mechanism was studied using a pilot depuration system. Both viruses were rapidly bioaccumulated by mussels and the maximal concentration of about 10(4) TCID50/ml was reached within 1.5 hours. Depuration was carried out up to 24 h; infectivity titer decreased to 10(2) TCID50/ml and 10(3.2) TCID50/ml within 6 h in hepatitis A virus and Poliovirus 1 contaminated mussels, respectively, but only a very slight further decrease was obtained after 24 h. E. coli was used as a control; within 24 h the concentration decreased from 40 to 2 bacteria/ml of mussel (MPN). The elimination of bacteria is not a reliable parameter to control the effectiveness of viral depuration.

Norovirus Detection in Groundwater

Waterborne disease outbreaks associated with groundwater consumption have been reported in different countries. Noroviruses are considered emerging pathogens, which cause gastroenteritis in all age groups worldwide and numerous outbreaks of noroviral gastroenteritis have been ascribed to contaminated drinking water. In Italy, few data on viral contamination of water environment and groundwater in particular are available. In this study, the presence of Norovirus GG I and GG II was investigated, using reverse transcription-polymerase chain reaction (RT-PCR) test, applied to groundwater samples collected in the Latium region in central Italy. Four out of 26 samples were positive (15.38%). Our results show both the presence of Norovirus in groundwater and the possibility to apply the RT-PCR tests for virus analysis.

Identification and Sequence Analysis of Hepatitis A Virus Detected in Market and Environmental Bivalve Molluscs

In Italy in 1998, hepatitis A virus (HAV) was responsible for an infectious disease transmitted by contaminated bivalve molluscs. To determine the presence of HAV in the bivalves collected during a 1-year follow-up study, hepatitis A RNA was extracted and amplified by a nested reverse transcriptase-PCR method overlapping the VP1/2A region. The HAV genome was detected in 24 (14.1%) of 170 samples: 19 clams (Tapes decussates and Tapes semidecussatus), 1 oyster (Crossostea gigas), and 4 mussels (Mytillus galloprovincialis). Eleven positive samples were collected from marketing areas, and 13 positive samples were collected from growing areas. Seventeen of the 24 positive samples had been taken from domestic products, and 7 had been imported. Sequence analysis showed the presence of genotypes IA and IB. Our results suggest significant presence of HAV in bivalves from both marketing (public consumption) and environmental (growing) areas.

Evaluation of the wastewater treatment plant of Rome airport

The wastewater plant of Rome airport, which receives all the sewage from the airport as well as the cess from aeroplanes, was analysed for microbiological parameters. From the bacteriological point of view, in the water and sludge samples the densities of the faecal indicator of pollution and the presence of Salmonella spp and Vibrio cholerae as bacteriological pathogens were determined. At the same time, samples were analysed for the presence of enteric viruses and phages. Overall, the mean reduction of the faecal coliforms was 96%, E. coli 92% and faecal streptococci 99%. Salmonella spp was identified in all but one of the final effluents and V. cholerae in 2/10. Enteric viruses were identified in all but one of the raw waters and in three samples of final effluent. Bacteriophages (somatic coliphage, F-plus phage and B40-8), were found in all the samples but irregularly. Phages and enteric viruses were also found in the prefilter membranes used for prefiltering the raw water samples.

Occurrence of Legionella in showers at recreational facilities

Critical environments, including water systems in recreational settings, represent an important source of Legionella pneumophila infection in humans. In order to assess the potential risk for legionellosis, we analyzed Legionella contamination of water distribution systems in 36 recreational facilities equipped with swimming pools. One hundred and sixty water samples were analyzed from shower heads or taps located in locker rooms or in bathrooms. By culture method and polymerase chain reaction, 41/160 samples were positive for Legionella from 12/36 recreational centers. Hotels (57.1%) and sports centers (41.2%) were the most contaminated. L. pneumophila serotypes 2-14 (25/41) were more frequently found than serotype 1 (10/41). Samples at temperature ≥30 °C were more frequently positive than samples at temperature <30 °C (n = 39 vs n = 2, p < 0.00001). The presence of L. pneumophila was investigated by comparison with heterotrophic plate count (HPC), an indicator of water quality. The presence of L. pneumophila was associated more frequently with high and intermediate HPC load at 37 °C, therefore should be considered a potential source when HPC at 37 °C is >10 CFU/mL. Maintenance, good hygiene practices, interventions on the hydraulic system and regular controls must be implemented to minimize exposure to L. pneumophila infection risk.

Concomitant poliovirus infection during an outbreak of hepatitis A

AIM OF THE STUDY The present study was designed to evaluate the possible co-infection, with other enteric viruses, during an outbreak of hepatitis A (HA). MATERIAL AND METHODS Forty-two stool samples and sera were collected during an outbreak of hepatitis A. Sera were analysed by the Abbott test for IgG-IgM anti-HAV antibodies. Stool samples were used to identify the presence of enteric viruses. HAV genome was identified by a RT-PCR test, other enteric viruses were identified, after cell passage and seroneutralization test on BGM cells, by RT-PCR and RFLP assay. RESULTS The samples were obtained from 27 employees of an industrial plant, nine household contacts and six non-employee controls. The attack rate was 12.5%, whereas the overall prevalence was 63%. In the employee group, 12 out of 27 stool samples were positive for the presence of HAV by reverse transcriptase polymerase chair reaction (RT-PCR). All the other samples (30) were negative. Five samples from employees, three from household contacts and one from non-employees were also found positive for enteroviruses. These viruses were classified by seroneutralization as poliovirus and RFLP assay as Sabin poliovirus type 1. Four samples were positive both for HAV and poliovirus. CONCLUSIONS This study confirms co-infection with different enteric viruses may occur and also emphasizes the wide circulation of HAV and the existence of silent infection with poliovirus.