Epidemiological surveillance of human enteric viruses by monitoring of different environmental matrices.
ABSTRACT In the aim of studying possible relations between viruses detected in clinical specimens and the ones found in different environmental matrices, in the period May 2004 to April 2005, the collection of faecal samples from gastroenteritis cases and the monthly monitoring of raw and treated wastewater, river water, seawater and mussels were carried out. The viruses considered for environmental monitoring were adenovirus, rotavirus, enterovirus, norovirus, hepatitis A virus (HAV) and Torque teno virus (TTV): they were searched for with PCR and RT-PCR and confirmed by gene sequencing. Faecal coliforms and somatic coliphages' counts were also determined. The surveillance of case detected 45 positive faecal samples out of 255 (17.6%) while 35 of 56 environmental samples (62.5%) resulted positive for at least one of the considered viruses. The detection of the same viral strain in the faeces of gastroenteritis cases and in water was possible for adenovirus and rotavirus, which were also predominant in environmental matrices; thus they could be considered as a reference for risk assessment.
- SourceAvailable from: Marco Verani[Show abstract] [Hide abstract]
ABSTRACT: The purpose of wastewater treatment is to minimize chemical and microbial contamination of recipient waters. The present study evaluated the impacts of meteorological variables, such as temperature and rainfall, on the removal of human viruses and indicators by a wastewater treatment plant servicing Pisa, Italy. Data were obtained during four sampling campaigns from 2007 to 2010. Wastewater sewage samples were analyzed for human adenovirus (HAdV) and norovirus using quantitative molecular techniques. In parallel, Escherichia coli, enterococci and somatic coliphages were measured, and meteorological and chemical data were recorded. We detected a continuous presence of HAdV in both influent and effluent samples with an average removal rate of 2.01 log Genomic Copies/l. An association between meteorological parameters and viral removal rates was detected only for rainfall and HAdV removal during a specific sampling campaign. No correlation was found between viral data and microbial, chemical and physical ones. Viral removal rates were not strongly influenced by meteorological conditions and were unrelated to other process indicators routinely monitored. Our results suggest that HAdV is a suitable parameter to assess the viral removal efficiency of wastewater treatment plants, particularly in the case of heavy rainfall.Food and Environmental Virology 03/2013; 5(1):69-76. · 2.51 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Torque teno virus (TTV, genus Alphatorquevirus, family Anelloviridae) is a DNA virus, highly prevalent in populations from around the world. TTV isolates have been classified into five main phylogenetic groups (1-5) showing a large genetic distance between them. The presence of TTV has been detected in feces. However, whether all five TTV genogroups are excreted in feces and the frequency of these events are presently unknown. The presence of TTV DNA was assessed in feces from 135 Brazilian (0-90 years old) patients with gastroenteritis by using three PCR methods, including real-time PCR. One hundred twenty one (91.1%) samples were positive with at least one method. Using a genogroup-specific assay, it was shown that all genogroups were present. Thirty-seven (27.4%), 27 (20.0%), 57 (42.2%), 29 (21.5%), and 33 (24.4%) fecal samples contained TTV isolates belonging to genogroups 1-5, respectively. Coinfections with two, three, four, and five TTV genogroups were found in 23 (17.0%), 15 (11.1%), 7 (5.2%), and 7 (5.2%) fecal samples, respectively. Thus, 52 (38.5%) samples contained more than one TTV genogroup. Viral loads ranged from 2.6 to 6.5 log genome equivalents per gram of feces. However, only moderate variations of viral load were noted depending on genogroup and number of coinfecting TTV genogroups. These results show a high prevalence and a diversity of TTV isolates in feces.Journal of Medical Virology 06/2011; 83(6):1107-11. · 2.37 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Despite their wide occurrence, cryptosporidiosis and giardiasis are considered neglected diseases by the World Health Organization. The epidemiology of these diseases and microsporidiosis in humans in developing countries is poorly understood. The high concentration of pathogens in raw sewage makes the characterization of the transmission of these pathogens simple through the genotype and subtype analysis of a small number of samples. The distribution of genotypes and subtypes of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in 386 samples of combined sewer systems from Shanghai, Nanjing and Wuhan and the sewer system in Qingdao in China was determined using PCR-sequencing tools. Eimeria spp. were also genotyped to assess the contribution of domestic animals to Cryptosporidium spp., G. duodenalis, and E. bieneusi in wastewater. The high occurrence of Cryptosporidium spp. (56.2%), G. duodenalis (82.6%), E. bieneusi (87.6%), and Eimeria/Cyclospora (80.3%) made the source attribution possible. As expected, several human-pathogenic species/genotypes, including Cryptosporidium hominis, Cryptosporidium meleagridis, G. duodenalis sub-assemblage A-II, and E. bieneusi genotype D, were the dominant parasites in wastewater. In addition to humans, the common presence of Cryptosporidium spp. and Eimeria spp. from rodents indicated that rodents might have contributed to the occurrence of E. bieneusi genotype D in samples. Likewise, the finding of Eimeria spp. and Cryptosporidium baileyi from birds indicated that C. meleagridis might be of both human and bird origins. The distribution of Cryptosporidium species, G. duodenalis genotypes and subtypes, and E. bieneusi genotypes in urban wastewater indicates that anthroponotic transmission appeared to be important in epidemiology of cryptosporidiosis, giardiasis, and microsporidiosis in the study areas. The finding of different distributions of subtypes between Shanghai and Wuhan was indicative of possible differences in the source of C. hominis among different areas in China.PLoS Neglected Tropical Diseases 09/2012; 6(9):e1809. · 4.57 Impact Factor