Detection of Helminth Ova in Wastewater Using Recombinase Polymerase Amplification Coupled to Lateral Flow Strips

Vivek B Ravindran,Sarvesh K Soni,Nicholas D Crosbie,Andrew S Ball,Aravind Surapaneni,Basma Khallaf

doi:10.3390/w12030691

Vivek B Ravindran, Sarvesh K Soni + Show 4 more

Open Access

https://doi.org/10.3390/w12030691

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Journal: Water	Publication Date: Mar 3, 2020
Citations: 10	License type: CC BY 4.0

Affiliation: RMIT University, Melbourne Water, South East Water (Australia)

Abstract

Ascaris lumbricoides is a major soil-transmitted helminth that is highly infective to humans. The ova of A. lumbricoides are able to survive wastewater treatment, thus making it an indicator organism for effective water treatment and sanitation. Hence, Ascaris ova must be removed from wastewater matrices for the safe use of recycled water. Current microscopic techniques for identification and enumeration of Ascaris ova are laborious and cumbersome. Polymerase chain reaction (PCR)-based techniques are sensitive and specific, however, major constraints lie in having to transport samples to a centralised laboratory, the requirement for sophisticated instrumentation and skilled personnel. To address this issue, a rapid, highly specific, sensitive, and affordable method for the detection of helminth ova was developed utilising recombinase polymerase amplification (RPA) coupled with lateral flow (LF) strips. In this study, Ascaris suum ova were used to demonstrate the potential use of the RPA-LF assay. The method was faster (< 30 min) with optimal temperature at 37 °C and greater sensitivity than PCR-based approaches with detection as low as 2 femtograms of DNA. Furthermore, ova from two different helminth genera were able to be detected as a multiplex assay using a single lateral flow strip, which could significantly reduce the time and the cost of helminth identification. The RPA-LF system represents an accurate, rapid, and cost-effective technology that could replace the existing detection methods, which are technically challenged and not ideal for on-site detection in wastewater treatment plants.

Highlights

The reuse of wastewater is widespread across the globe, especially in regions with water scarcity [1,2]
Recycled water can be utilised in irrigation but—if not treated effectively—can pose risk for public health owing to the pathogens present in the recycled water used for irrigation [3,4,5]
The Recombinase polymerase amplification (RPA)-lateral flow (LF) reported in this study was rapid and highly sensitive in the detection of A. suum ova

Summary

Introduction

The reuse of wastewater is widespread across the globe, especially in regions with water scarcity [1,2]. Recycled water can be utilised in irrigation but—if not treated effectively—can pose risk for public health owing to the pathogens present in the recycled water used for irrigation [3,4,5]. Soil-transmitted helminth ova can survive for several months or years in the environment and are a concern where wastewater and sludge reuse are prominent [6,7]. In 1989, the World Health Organization (WHO) focused on the helminth-associated infections that occur due to poor sanitation, poor hygiene, and inadequate water quality [8,9,10]. Soil-transmitted helminth (STH) infections are of severe concern, affecting nearly one-third of the world’s population [9,10,11]. Ascaris lumbricoides is the major STH, afflicting more than one billion people

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