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. 2021 Mar;130(3):971-981.
doi: 10.1111/jam.14807. Epub 2020 Aug 14.

Validation of the bag-mediated filtration system for environmental surveillance of poliovirus in Nairobi, Kenya

C S Fagnant-Sperati  1 , Y Ren  2 , N A Zhou  1 , E Komen  3 , B Mwangi  3 , J Hassan  3 , A Chepkurui  3 , R Nzunza  3 , J Nyangao  3 , W B van Zyl  4 , M Wolfaardt  4 , P N Matsapola  4 , F B Ngwana  4 , S Jeffries-Miles  5 , A Coulliette-Salmond  6 , S Peñaranda  6 , E Vega  6 , J H Shirai  1 , A L Kossik  1 , N K Beck  1 , D S Boyle  7 , C C Burns  6 , M B Taylor  4 , P Borus  3 , J S Meschke  1
Affiliations

Validation of the bag-mediated filtration system for environmental surveillance of poliovirus in Nairobi, Kenya

C S Fagnant-Sperati et al. J Appl Microbiol. 2021 Mar.

Abstract

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 < 1 × 10-5 ).

Conclusions: Poliovirus 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.

Keywords: Kenya; ViroCap; enteric viruses; environmental surveillance; filtration; poliovirus; wastewater.

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Conflict of interest statement

No conflict of interest declared.

Figures

Figure 1
Figure 1
Kenya bag‐mediated filtration system (BMFS) and two‐phase separation method comparison study design. (a) Comparison of two‐phase and BMFS samples, 29 September 2015–15 February 2016. (b) Comparison of two‐phase and BMFS samples, 16 February 2016–14 February 2017. KEMRI is Kenya Medical Research Institute. UP is University of Pretoria. CDC is Centers for Disease Control and Prevention. BMFS is bag‐mediated filtration system. ITD is intratypic differentiation. GLMM is generalized linear mixed model.
Figure 2
Figure 2
Poliovirus (PV) and non‐polio enterovirus (NPEV) detection in bag‐mediated filtration system (BMFS) and two‐phase samples. SL1 is Sabin‐like PV type 1. SL2 is Sabin‐like PV type 2. SL3 is Sabin‐like PV type 3. VDPV2 is vaccine‐derived PV type 2. NEV is non‐enterovirus. bOPV is bivalent oral polio vaccine. tOPV is trivalent oral polio vaccine (formula image SL1; (formula image SL3; (formula image SL1 & SL3; (formula image SL2; (formula image SL1 & SL2; (formula image SL2 & SL3; (formula image SL1, SL2 & SL3; (formula image SL3 & VDPV2; (formula image negative for PV; (formula image NPEV (alone or with PV); (formula image NPEV & NEV (alone or with PV); (formula image no data; (formula image Vaccine switch to bOPV (removal of SL2); (formula image National Immunization Day (tOPV); (formula image Sub‐National Immunization Day (tOPV); (formula image Sub‐National Immunization Day (bOPV).
See this image and copyright information in PMC

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