Acute flaccid paralysis (AFP) surveillance has been used to identify polio cases and target vaccination campaigns since the inception of the Global Poliovirus Eradication Initiative (GPEI) in 1988. To date, only Afghanistan and Pakistan have failed to interrupt wild poliovirus transmission. Circulation of vaccine-derived polioviruses (VDPV) continues to be a problem in high-risk areas of the Eastern Mediterranean, African, and Southeast Asian regions. Environmental surveillance (ES) is an important adjunct to AFP surveillance, helping to identify circulating polioviruses in problematic areas. Stools from AFP cases and contacts (>200,000 specimens/year) and ES samples (>642 sites) are referred to 146 laboratories in the Global Polio Laboratory Network (GPLN) for testing. Although most World Health Organization supported laboratories use the two-phase separation method due to its simplicity and effectiveness, alternative simple, widely available, and cost-effective methods are needed. The CAF (Concentration and Filtration Elution) method was developed from existing filtration methods to handle any type of sewage or residual waters. At $1020 US per sample for consumable materials, CAF is cost effective, and all equipment and reagents are readily available from markets and suppliers globally. The report describes the results from a parallel study of CAF method with the standard two-phase separation method. The study was performed with samples collected from five countries (Guatemala, Hati, Thailand, Papua New Guinea, and the Philippines), run in three laboratories(United States, Thailand and in the Philippines) to account for regional and sample-to-sample variability. Samples from each site were divided into two 500ml aliquots and processed by both methods, with no other additional concentration or manipulation. The results of 338 parallel-tested samples show that the CAF method is more sensitive than the two-phase separation method for detection of non-polio enteroviruses (p-value < 0.0001) and performed as well as the two-phase separation method for polioviruses detection with no significant difference (p-value > 0.05). The CAF method is a robust, sensitive, and cost-effective method for isolating enteroviruses from residual waters. Copyright 2022 Belgasmi, Miles, Sayyad, Wong, Harrington, Gerloff, Coulliette-Salmond, Guntapong, Tacharoenmuang, Ayutthaya, Apostol, Valencia, Burns, Benito and Vega.

Environmental surveillance was recommended for risk mitigation in a novel oral polio vaccine-2 (nOPV2) clinical trial (M5-ABMG) to monitor excretion, potential circulation, and loss of attenuation of the two nOPV2 candidates. The nOPV2 candidates were developed to address the risk of poliovirus (PV) type 2 circulating vaccine-derived poliovirus (cVDPV) as part of the global eradication strategy. Between November 2018 and January 2020, an environmental surveillance study for the clinical trial was conducted in parallel to the M5-ABMG clinical trial at five locations in Panama. The collection sites were located upstream from local treatment plant inlets, to capture the excreta from trial participants and their community. Laboratory analyses of 49 environmental samples were conducted using the two-phase separation method. Novel OPV2 strains were not detected in sewage samples collected during the study period. However, six samples were positive for Sabin-like type 3 PV, two samples were positive for Sabin-like type 1 PV, and non-polio entero-viruses NPEVs were detected in 27 samples. One of the nOPV2 candidates has been granted Emergency Use Listing by the World Health Organization and initial use started in March 2021. This environmental surveillance study provided valuable risk mitigation information to support the Emergency Use Listing application. Copyright © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Haïti is at risk for wild poliovirus (WPV) importation and circulation, as well as vaccine-derived poliovirus (VDPV) emergence. Environmental surveillance (ES) for polioviruses was established in Port au Prince and Gonaïves in 2016. During 2017-2019, initial ES sites were re-evaluated, and ES was expanded into Cap Haïtien and Saint Marc. Wastewater samples and data on weather, hour of collection, and sample temperature and pH were collected every 4 weeks during March 2017-December 2019 (272 sampling events) from 21 sites in Cap Haïtien, Gonaïves, Port au Prince, and Saint Marc. Samples were processed for the detection of polio and non-polio enteroviruses using the two-phase and "Concentration and Filter Elution" methodologies. Polioviruses were serotyped and underwent intra-typic characterization. No WPV or VDPVs were isolated. Sabin-like polioviruses (oral vaccine strain) of serotypes 1 and 3 were sporadically detected. Five of six (83%), one of six (17%), five of six (83%), and two of three (67%) sites evaluated in Cap Haïtien, Gonaïves, Port au Prince, and Saint Marc, respectively, had enterovirus isolation from >50% of sampling events; these results and considerations, such as watershed population size and overlap, influence of sea water, and excessive particulates in samples, were factors in site retention or termination. The evaluation of 21 ES sampling sites in four Haïtian cities led to the termination of 11 sites. Every-four-weekly sampling continues at the remaining 10 sites across the four cities as a core Global Polio Eradication Initiative activity.

AIMS: This study compared the bag-mediated filtration system (BMFS) and standard WHO two-phase separation methods for poliovirus (PV) environmental surveillance, examined factors impacting PV detection, and monitored Sabin-like (SL) PV type 2 presence with withdrawal of oral polio vaccine type 2 (OPV2) in April 2016. METHODS AND RESULTS: Environmental samples were collected in Nairobi, Kenya (Sept 2015-Feb 2017), concentrated via BMFS and two-phase separation methods, then assayed using the WHO PV isolation algorithm and intratypic differentiation diagnostic screening kit. SL1, SL2, and SL3 were detected at higher rates in BMFS than two-phase samples (p<0.05). In BMFS samples, SL PV detection did not significantly differ with volume filtered, filtration time, or filter shipment time (p>0.05), while SL3 was detected less frequently with higher shipment temperatures (p=0.027). SL2 was detected more frequently before OPV2 withdrawal in BMFS and two-phase samples (p<1x10(-5) ). CONCLUSIONS: PV was detected at higher rates with the BMFS, a method that includes a secondary concentration step, than using the standard WHO two-phase method. SL2 disappearance from the environment was commensurate with OPV2 withdrawal. SIGNIFICANCE AND IMPACT OF THE STUDY: The BMFS offers comparable or improved PV detection under the conditions in this study, relative to the two-phase method.

The infection of healthcare workers during the 2013 -2016 Ebola outbreak raised concerns about fomite transmission. In the wake of the Coronavirus Disease 2019 (COVID-19) pandemic, investigations are ongoing to determine the role of fomites in coronavirus transmission as well. The bacteriophage Phi 6 has a phospholipid envelope and is commonly used in environmental studies as a surrogate for human enveloped viruses. The persistence of Phi 6 was evaluated as a surrogate for EBOV and coronaviruses on porous and nonporous hospital surfaces. Phi 6 was suspended in a body fluid simulant and inoculated onto 1 cm(2) coupons of steel, plastic, and two fabric curtain types. The coupons were placed at two controlled absolute humidity (AH) levels; a low AH of 3.0 g/m(3) and a high AH of 14.4 g/m(3) Phi 6 declined at a slower rate on all materials under low AH conditions with a decay rate of 0.06 log10PFU/d to 0.11 log10PFU/d, as compared to the higher AH conditions with a decay rate of 0.65 log10PFU/h to 1.42 log10PFU/d. There was a significant difference in decay rates between porous and non-porous surfaces at both low AH (P < 0.0001) and high AH (P < 0.0001). Under these laboratory-simulated conditions, Phi 6 was found to be a conservative surrogate for EBOV under low AH conditions, in that it persisted longer than Ebola virus in similar AH conditions. Additionally, some coronaviruses persist longer than phi6 under similar conditions, therefore Phi6 may not be a suitable surrogate for coronaviruses.IMPORTANCE Understanding the persistence of enveloped viruses helps inform infection control practices and procedures in healthcare facilities and community settings. These data convey to public health investigators that enveloped viruses can persist and remain infective on surfaces, thus demonstrating a potential risk for transmission. Under these laboratory-simulated western indoor hospital conditions, Phi 6 was used to assess suitability as a surrogate for environmental persistence research related to enveloped viruses, including EBOV and coronaviruses.

Poliovirus (PV) environmental surveillance was established in Haiti in three sites each in Port-au-Prince and Gonaives, where sewage and fecal-influenced environmental open water channel samples were collected monthly from March 2016 to February 2017. The primary objective was to monitor for the emergence of vaccine-derived polioviruses (VDPVs) and the importation and transmission of wild polioviruses (WPVs). A secondary objective was to compare two environmental sample processing methods, the gold standard two-phase separation method and a filter method (bag-mediated filtration system [BMFS]). In addition, non-polio enteroviruses (NPEVs) were characterized by next-generation sequencing using Illumina MiSeq to provide insight on surrogates for PVs. No WPVs or VDPVs were detected at any site with either concentration method. Sabin (vaccine) strain PV type 2 and Sabin strain PV type 1 were found in Port-au-Prince, in March and April samples, respectively. Non-polio enteroviruses were isolated in 75-100% and 0-58% of samples, by either processing method during the reporting period in Port-au-Prince and Gonaives, respectively. Further analysis of 24 paired Port-au-Prince samples confirmed the detection of a human NPEV, and echovirus types E-3, E-6, E-7, E-11, E-19, E-20, and E-29. The comparison of the BMFS filtration method to the two-phase separation method found no significant difference in sensitivity between the two methods (mid-P-value = 0.55). The experience of one calendar year of sampling has informed the appropriateness of the initially chosen sampling sites, importance of an adequate PV surrogate, and robustness of two processing methods.

The bag-mediated filtration system (BMFS) was developed to facilitate poliovirus (PV) environmental surveillance, a supplement to acute flaccid paralysis surveillance in PV eradication efforts. From April to September 2015, environmental samples were collected from four sites in Nairobi, Kenya, and processed using two collection/concentration methodologies: BMFS (> 3 L filtered) and grab sample (1 L collected; 0.5 L concentrated) with two-phase separation. BMFS and two-phase samples were analyzed for PV by the standard World Health Organization poliovirus isolation algorithm followed by intratypic differentiation. BMFS samples were also analyzed by a cell culture independent real-time reverse transcription polymerase chain reaction (rRT-PCR) and an alternative cell culture method (integrated cell culture-rRT-PCR with PLC/PRF/5, L20B, and BGM cell lines). Sabin polioviruses were detected in a majority of samples using BMFS (37/42) and two-phase separation (32/42). There was statistically more frequent detection of Sabin-like PV type 3 in samples concentrated with BMFS (22/42) than by two-phase separation (14/42, p = 0.035), possibly due to greater effective volume assayed (870 mL vs. 150 mL). Despite this effective volume assayed, there was no statistical difference in Sabin-like PV type 1 and Sabin-like PV type 2 detection between these methods (9/42 vs. 8/42, p = 0.80 and 27/42 vs. 32/42, p = 0.18, respectively). This study demonstrated that BMFS can be used for PV environmental surveillance and established a feasible study design for future research.