Laboratory Surveillance of Polio and Other Enteroviruses in High-Risk Populations and Environmental Samples

Abstract

In the context of poliomyelitis eradication, a reinforced supplementary laboratory surveillance of enteroviruses was implemented in Greece. Between 2008 and 2014, the Hellenic Polioviruses/Enteroviruses Reference Laboratory performed detailed supplementary surveillance of circulating enteroviruses among healthy individuals in high-risk population groups, among immigrants from countries in which poliovirus is endemic, and in environmental samples. In total, 722 stool samples and 179 sewage water samples were included in the study. No wild-type polioviruses were isolated during these 7 years of surveillance, although two imported vaccine polioviruses were detected. Enterovirus presence was recorded in 25.3 and 25.1% of stool and sewage water samples, respectively. Nonpolio enteroviruses isolated from stool samples belonged to species A, B, or C; coxsackievirus A24 was the most frequently identified serotype. Only enteroviruses of species B were identified in sewage water samples, including four serotypes of echoviruses and four serotypes of coxsackie B viruses. Phylogenetic analysis revealed close genetic relationships among virus isolates from sewage water samples and stool samples, which in most cases fell into the same cluster. To the best of our knowledge, this is the first study to compare enterovirus serotypes circulating in fecal specimens of healthy individuals and environmental samples, emphasizing the burden of enterovirus circulation in asymptomatic individuals at high risk. Given that Greece continues to receive a large number of short-term arrivals, students, migrants, and refugees from countries in which poliovirus is endemic, it is important to guarantee high-quality surveillance in order to maintain its polio-free status until global eradication is achieved. IMPORTANCE This article summarizes the results of supplementary poliovirus surveillance in Greece and the subsequent characterization of enteroviral circulation in human feces and the environment. The examination of stool samples from healthy refugees and other individuals in "high-risk" groups for poliovirus enables the identification of enterovirus cases and forms the basis for further investigation of the community-level risk of viral transmission. In addition, the examination of composite human fecal samples through environmental surveillance links poliovirus and nonpoliovirus isolates from unknown individuals to populations served by the sewage or wastewater system. Supplementary surveillance is necessary to comply with the prerequisites imposed by the World Health Organization for monitoring the emergence of vaccine-derived polioviruses, reemergence of wild polioviruses, or disappearance of all vaccine-related strains in order for countries such as Greece to maintain their polio-free status and contribute to global poliovirus eradication.

Environmental Surveillance for Poliovirus and Other Enteroviruses: Long-Term Experience in Moscow, Russian Federation, 2004–2017

“…Since vaccination against poliomyelitis with OPV is carried out in Russia in accordance with the National Vaccination Schedule throughout the year, which excludes the effect of vaccination campaigns on the frequency of EV release, this suggests that the Moscow region is characterized by pronounced summer–autumn seasonality of NPEV circulation among the population. The high prevalence of the EV-B species among the NPEV viruses is consistent with the results of studies carried out in Europe [31,32,33,34,37,45] and seems to reflect the epidemiology of NPEV in the region. Viruses E7, E11 and E19 were isolated mainly from wastewater, which indicates the silent circulation of these types in the population and their low pathogenicity.…”

“…Utility and efficiency of sewage monitoring relies upon many factors, including general sanitary, climate conditions, sampling and concentrating methods, sampling points, and screening methodology. The virus isolation rates in Moscow (mean over 10 years ranged from 14.4 to 34.6% at different facilities, 20.0% on average in the city) were comparable with other studies that used two-phase concentration (mixing of clarified wastewater with two polymers (dextran and polyethylene glycol) and subsequent settling, detailed in the WHO guidelines) and cell culture isolation: 22% and 30.1% in Italy [32,33], 25% in Greece [34]. Higher virus detection rates were observed at low-throughput facilities TP3 (34.6%) and TP4 (32.6%) in Moscow.…”

Molecular Epidemiology of Enterovirus in Children with Central Nervous System Infections

“…Limited data have been published regarding circulating EVs involved in pediatric CNS infection in Europe since 2017 [ 12 ]. Although in Greece, there is a reference center for enteroviruses based on the Hellenic Pasteur Institute, the last published data stop in 2015 [ 13 , 14 ]. The aim of this study was to investigate the molecular epidemiology of EV causing CNS infections in children during a 3-year period.…”

COVID-19 Crisis Creates Opportunity towards Global Monitoring & Surveillance

“…Therefore, employing metagenomics sequencing (mNGS) and RT-qPCR on pooled wastewater/sewerage samples to assess the community viral load and linking it with the number of people shedding virus may help in assessing risk [161,258,259]. Additionally, genome sequencing provides detailed data regarding the presence of a specific haplotype in certain areas [260,261] stated that raw and treated wastewater samples collected from an Italian plant in Milano were tested for SARS-CoV-2.…”

“…In addition, both PV and SARS-CoV-2 are single-stranded, positive-sense RNA genomes, and both can exist either symptomatically, with a similar incubation period, and also circulate asymptomatically or silently within-population [128,129], heavily relying on human behaviours. In order to better develop epidemiological models of disease spread in diverse environments, such as those prevailing in HICs and LMICs, it will be essential to trace the circulation of SARS-CoV-2 mostly in wastewater, in particular in hotspots, along the lines of polio environmental surveillance campaigns that have been carried out in the past [258,259].…”