Stability of human enteric viruses in seawater samples from mollusc depuration tanks coupled with ultraviolet irradiation.

AIMS: To evaluate the stability in seawater of human adenovirus (HAdV2), murine norovirus (MNV-1) and hepatitis A virus (HAV) in a shellfish depuration system with and without ultraviolet (UV) treatment. METHODS AND RESULTS: Seawater was seeded with viruses and disinfected using a 36 W lamp. Samples were collected at 24, 48, 72, 96 and 120 h; viruses were concentrated and the viral decay was evaluated using molecular and cell culture methods. Based on the molecular results, at 120 h of disinfection, there was a reduction of more than 3 log(10) for HAdV2 and HAV; MNV-1, a 4.5 log(10) reduction was observed at 72 h. Infectious MNV-1 was not detected after 72 h of treatment; while HAdV2 remained infectious. Seawater not treated demonstrated a progressive viral reduction for the three viruses tested. CONCLUSIONS: The UV reduced the number of viral particles, and the results indicate there is natural and gradual decrease of viral load and viability in seawater. SIGNIFICANCE AND IMPACT OF THE STUDY: UV irradiation is the method of choice for shellfish depuration in many countries; this work showed useful information about the viral stability in seawater and application of UV to water disinfection to be used in shellfish depuration tanks.

Microbiological and physicochemical analysis of the coastal waters of southern Brazil.

The aim of this study was to assess the impact of sewage discharge on coastal waters by evaluating the influence of physicochemical parameters on the presence of enteric microorganisms in seawater samples collected from 11 beaches in Florianopolis, Santa Catarina, Brazil, over a one-year period (August 2009 to July 2010). Samples were assessed for the presence of human adenoviruses (HAdV), polyomavirus (JCPyV), hepatitis A virus (HAV), and noroviruses (HuNoV GI and GII). Escherichia coli and physicochemical parameters (salinity, temperature, pH and dissolved oxygen) were also evaluated. From the 132 samples analyzed, 55% were positive for HAdV, 51.5% for HAV, 7.5% for HuNoV GI, 4.5% for HuNoV GII, and 3% for JCPyV. E. coli levels ranged from 8 to 1325 CFU/100mL at all sites. The overall results highlight the problem of sewage discharge into coastal waters and confirm that there is no correlation between viral presence and bacterial contamination.

Assessment of adenovirus, hepatitis A virus and rotavirus presence in environmental samples in Florianopolis, South Brazil.

AIMS: To assess the presence of human adenovirus (HAdV), hepatitis A (HAV) virus and rotavirus A (RV-A) in environmental samples from the Southern region of Brazil and to provide viral contamination data for further epidemiological studies and governmental actions. METHODS AND RESULTS: Water samples from various sources (seawater, lagoon brackish water, urban wastewater, drinking water sources-with and without chlorination and water derived from a polluted creek) and oysters of two growing areas were analysed by enzymatic amplification (nested PCR and RT-PCR), quantification of HAdV genome (qPCR) and viral viability assay by integrated cell culture-PCR (ICC-PCR). From June 2007 to May 2008 in a total of 84 water samples, 54 (64·2%) were positive for HAdV, 16 (19%) for RV-A and 7 (8·3%) for HAV. Viability assays showed nonpositive samples for HAV; though, infectious viruses were confirmed for RV-A (12·5%) and HAdV (88·8%). Oyster samples by PCR were positive for HAdV (87·5%) and RV-A (8·3%), but none for HAV. Quantitative PCR in oysters showed means loads in genomic copies (gc) of 9·1 × 10(4) gc g(-1) (oyster farm south) and 1·5 × 10(5) gc g(-1) (oyster farm north) and in waters ranging from 2·16 × 10(6) (lagoon water) to 1·33 × 10(7) gc l(-1) (untreated drinking water). CONCLUSIONS: This study has shown a widespread distribution of the analysed viruses in this particular region with high loads of HAdV in the environment which suggests the relevance of evaluating these viruses as positive indicators of viral contamination of water. SIGNIFICANCE AND IMPACT OF THE STUDY: The environmental approach in this study provides data concerning the prevalence, viability and quantification of enteric viruses in environmental waters and oysters in the South region of Brazil and has indicated that their presence might pose a risk to population in contact with the environmental samples searched.