Surveillance and analysis of enteroviruses in water environments in Shenzhen from 2010 to 2011

Molecular characterization of enterovirus detected in cerebrospinal fluid and wastewater samples in Monastir, Tunisia, 2014-2017

Background

Enteroviruses (EVs) are considered the main causative agents responsible for aseptic meningitis worldwide. This study was conducted in the Monastir region of Tunisia in order to know the prevalence of EV infections in children with meningitis symptoms. Detected EV types were compared to those identified in wastewater samples.

Methods

Two hundred CSF samples collected from hospitalized patients suspected of having aseptic meningitis for an EV infection between May 2014 and May 2017 and 80 wastewater samples collected in the same time-period were analyzed. EV detection and genotyping were performed using PCR methods followed by sequencing. Phylogenetic analyses in the 3′-VP1 region were also carried-out.

Results

EVs were detected in 12% (24/200) CSF and in 35% (28/80) wastewater samples. EV genotyping was reached in 50% (12/24) CSF-positive samples and in 64% (18/28) sewage. Most frequent types detected in CSF were CVB3, E-30 and E-9 (25% each). In wastewater samples, the same EVs were identified, but also other types non-detected in CSF samples, such as E-17,CVA9 and CVB1 from EV species B, and EV-A71 and CVA8 from EV-A, suggesting their likely lower pathogenicity. Phylogenetic analysis showed that within the same type, different strains circulate in Tunisia. For some of the EV types such as E-9, E-11 or CVB3, the same strains were detected in CSF and wastewater samples.

Conclusions

Epidemiological studies are important for the surveillance of the EV infections and to better understand the emergence of certain types and variants.

A consecutive centrifugal method for concentration of human enteric viruses in water samples

A consecutive centrifugal method was developed to concentrate enteric viruses from water. Using five selected human enteric viruses, the recovery rates were evaluated and compared with results from NanoCeram filtration methods. The highest recovery rate was achieved for coxsackievirus (78.11 %, 42.97-101.39), and the lowest rate was for adenovirus (32.84 %, 19.68-66.20). In comparison with NanoCeram disc filtration with beef-extract flocculation (BE), the recovery rate was increased for all viruses. The rate of increase varied from a low of 8.24 % (astroviruses) to a high of 24.22 % (noroviruses). The NanoCeram filtration with BE was further modified by NaPP buffer plus one-step centrifugation using a Centricon plus-70 device. The modified method further increased the concentrations of viruses in the sample. Virus concentration was increased to 19.45 ± 7.19-fold for rotavirus, 19.40 ± 6.54-fold for norovirus, 16.10 ± 7.61-fold for coxsackievirus, 12.80 ± 3.00-fold for astrovirus and 11.97 ± 6.94-fold for adenovirus compared to the NanoCeram filtration with BE. Subsequent cell culture showed that the infectivity of the viruses was not altered by any of the three methods. Three methods will provide testing labs with choices for cost-effective approaches to concentrate viruses from water.

Environmental surveillance of human enteroviruses in Shandong Province, China, 2008 to 2012: serotypes, temporal fluctuation, and molecular epidemiology

Environmental surveillance is an effective approach in investigating the circulation of polioviruses (PVs) and other human enteroviruses (EVs) in the population. The present report describes the results of environmental surveillance conducted in Shandong Province, China, from 2008 to 2012. A total of 129 sewage samples were collected, and 168 PVs and 1,007 nonpolio enteroviruses (NPEVs) were isolated. VP1 sequencing and typing were performed on all isolates. All PV strains were Sabin-like, with the numbers of VP1 substitutions ranging from 0 to 7. The NPEVs belonged to 19 serotypes, and echovirus 6 (E6), E11, coxsackievirus B3 (CVB3), E3, E12, and E7 were the six main serotypes, which accounted for 18.3%, 14.8%, 14.5%, 12.9%, 9.0%, and 5.7% of NPEVs isolated, respectively. Typical summer-fall peaks of NPEV were observed in the monthly distribution of isolation, and an epidemic pattern of annual circulation was revealed for the common serotypes. Phylogenetic analysis was performed on environmental CVB3 and E3 strains with global reference strains and local strains from aseptic meningitis patients. Shandong strains formed distinct clusters, and a close relationship was observed between local environmental and clinical strains. As an EV-specific case surveillance system is absent in China and many other countries, continuous environmental surveillance should be encouraged to investigate the temporal circulation and phylogeny of EVs in the population.

Emergence, circulation, and spatiotemporal phylogenetic analysis of coxsackievirus a6- and coxsackievirus a10-associated hand, foot, and mouth disease infections from 2008 to 2012 in Shenzhen, China

Sporadic hand, foot, and mouth disease (HFMD) outbreaks and other infectious diseases in recent years have frequently been associated with certain human enterovirus (HEV) serotypes. This study explored the prevalences and genetic characteristics of non-HEV71 and non-coxsackievirus A16 (CV-A16) human enterovirus-associated HFMD infections in Shenzhen, China. A total of 2,411 clinical stool specimens were collected from hospital-based surveillance for HFMD from 2008 to 2012. The detection of HEV was performed by real-time reverse transcription-PCR (RT-PCR) and RT-seminested PCR, and spatiotemporal phylogenetic analysis was performed based on the VP1 genes. A total of 1,803 (74.8%) strains comprising 28 different serotypes were detected. In the past 5 years, the predominant serotypes were HEV71 (60.0%), followed by CV-A16 (21.2%) and two uncommon serotypes, CV-A6 (13.0%) and CV-A10 (3.3%). However, CV-A6 replaced CV-A16 as the second most common serotype between 2010 and 2012. As an emerging pathogen, CV-A6 became as common a causative agent of HFMD as HEV71 in Shenzhen in 2012. Phylogenetic analysis revealed that little variation occurred in the Chinese HEV71 and CV-A16 strains. The genetic characteristics of the Chinese CV-A6 and CV-A10 strains displayed geographic differences. The CV-A6 and CV-A10 strains circulating in Shenzhen likely originated in Europe. It was found that human enteroviruses have a high mutation rate due to evolutionary pressure and frequent recombination (3.2 × 10(-3) to 6.4 ×10(-3) substitutions per site per year for HEV71, CV-A6, CV-A16, and CV-A10). Since certain serotypes are potential threats to the public health, this study provides further insights into the significance of the epidemiological surveillance of HFMD.