Hepatitis A virus in environmental water samples from the Amazon Basin

142

To assess the presence of the four main viruses responsible for human acute gastroenteritis in a hydrographic network impacted by a disordered urbanization process, a 1-year study was performed involving water sample collection from streams in the hydrographic basin surrounding the city of Manaus, Amazonas, Brazil. Thirteen surface water sample collection sites, including different areas of human settlement characterized as urban, rural, and primary forest, located in the Tarumã-Açu, São Raimundo, Educandos, and Puraquequara microbasins, were defined with a global positioning system. At least one virus was detected in 59.6% (31/52) of the water samples analyzed, and rotavirus was the most frequent (44.2%), followed by human adenovirus (30.8%), human astrovirus (15.4%), and norovirus (5.8%). The viral contamination observed mainly in the urban streams reflected the presence of a local high-density population and indicated the gastroenteritis burden from pathogenic viruses in the water, principally due to recreational activities such as bathing. The presence of viral genomes in areas where fecal contamination was not demonstrated by bacterial indicators suggests prolonged virus persistence in aquatic environments and emphasizes the enteric virus group as the most reliable for environmental monitoring.Although water is recognized as the most precious natural resource on our planet, human activities disregard this fact by continually polluting freshwater bodies. Increasing worldwide awareness of the poor quality of potable water has occurred mainly due to the significant increase in human morbidity and mortality. More than 2.2 million people die every year from diseases associated with poor quality water and sanitary conditions, mostly in developing countries. The presence of pathogenic enteric microorganisms in aquatic environments reveals how human health can be affected by contamination from sewage discharge into surface waters.

Section: Vol 74 2008 Gastroenteritis Viruses In the Water Streams Osupporting

confidence: 57%

Molecular Detection and Characterization of Gastroenteritis Viruses Occurring Naturally in the Stream Waters of Manaus, Central Amazônia, Brazil

Miagostovich

Ferreira

Guimarães

et al. 2008

142

“…This may be due to the nature of our samples, or it could be due to the qPCR assay used in this study, which could target two main types of HPyV (polyomaviruses JC and BK [JCPyV and BKPyV]), whereas the assay used in the previous study mainly targets JCPyV. Even though some studies have reported the presence of HAV in environmental water media (8,13,40,48), no HAV was detected in any of our biosolid samples. The occurrence of HAV indicates that the risk of transporting HAV from landapplied biosolids to the natural environment is minimal.…”

Section: Discussionmentioning

confidence: 86%

Quantification of Enteric Viruses, Pathogen Indicators, and Salmonella Bacteria in Class B Anaerobically Digested Biosolids by Culture and Molecular Methods

Wong

Onan

Xagoraraki

2010

The most common class B biosolids in the United States are generated by mesophilic anaerobic digestion (MAD), and MAD biosolids have been used for land application. However, the pathogen levels in MAD biosolids are still unclear, especially with respect to enteric viruses. In this study, we determined the occurrence and the quantitative levels of enteric viruses and indicators in 12 MAD biosolid samples and of Salmonella enterica in 6 MAD biosolid samples. Three dewatered biosolid samples were also included in this study for purposes of comparison. Human adenoviruses (

“…Filtration on the scale of 100-liter samples is difficult to accomplish in the field, and many methods require expensive, expendable filters that cannot be reused. A number of recent studies have taken the optional approach of concentrating 1-to 2-liter volumes of surface water by membrane filtration to test for human viruses (6,20,21,27,33,(44)(45)(46)(47)(48); however, few comparisons of method effectiveness for virus recovery have been carried out. Hence, we compared the performance of three relatively simple virus concentration methods to determine their efficiency in recovering two viral MST markers (HAdVs and HPyVs) in tap and river water samples spiked with raw sewage.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Concentration Methods for Quantitative Detection of Sewage-Associated Viral Markers in Environmental Waters

Ahmed

Harwood

Gyawali

et al. 2015

118

dPathogenic human viruses cause over half of gastroenteritis cases associated with recreational water use worldwide. They are relatively difficult to concentrate from environmental waters due to typically low concentrations and their small size. Although rapid enumeration of viruses by quantitative PCR (qPCR) has the potential to greatly improve water quality analysis and risk assessment, the upstream steps of capturing and recovering viruses from environmental water sources along with removing PCR inhibitors from extracted nucleic acids remain formidable barriers to routine use. Here, we compared the efficiency of virus recovery for three rapid methods of concentrating two microbial source tracking (MST) viral markers human adenoviruses (HAdVs) and polyomaviruses (HPyVs) from one liter tap water and river water samples on HA membranes (90 mm in diameter). Samples were spiked with raw sewage, and viral adsorption to membranes was promoted by acidification (method A) or addition of MgCl 2 (methods B and C). Viral nucleic acid was extracted directly from membranes (method A), or viruses were eluted with NaOH and concentrated by centrifugal ultrafiltration (methods B and C). No inhibition of qPCR was observed for samples processed by method A, but inhibition occurred in river samples processed by B and C. Recovery efficiencies of HAdVs and HPyVs were ϳ10-fold greater for method A (31 to 78%) than for methods B and C (2.4 to 12%). Further analysis of membranes from method B revealed that the majority of viruses were not eluted from the membrane, resulting in poor recovery. The modification of the originally published method A to include a larger diameter membrane and a nucleic acid extraction kit that could accommodate the membrane resulted in a rapid virus concentration method with good recovery and lack of inhibitory compounds. The frequently used strategy of viral absorption with added cations (Mg 2؉) and elution with acid were inefficient and more prone to inhibition, and will result in underestimation of the prevalence and concentrations of HAdVs and HPyVs markers in environmental waters. Discharges from sewage treatment plants (STPs), storm water drains, improperly designed septic systems, and fecal contamination from livestock and wildlife are known to degrade environmental water quality in terms of elevating fecal indicator bacteria and possibly pathogen concentrations (1-5). Fecal indicator bacteria such as Escherichia coli and Enterococcus spp. have been widely used as an indirect measure of microbial risk associated with environmental waters. However, identifying the health risks associated with enteric viruses and protozoa by monitoring fecal indicator bacteria has been questioned (5-8).The risk of infectious disease associated with recreational water use may well be of viral etiology (9). The transmission of these viruses occurs via the fecal-oral route, nasal mucosa or the conjunctiva and the infected individual may shed up to 10 11 viral particles/gram of feces (10). Some of these viruses are more res...