Quantitative PCR and Digital PCR for Detection ofAscaris lumbricoidesEggs in Reclaimed Water

Abstract

The reuse of reclaimed water from wastewater depuration is a widespread and necessary practice in many areas around the world and must be accompanied by adequate and continuous quality control. Ascaris lumbricoides is one of the soil-transmitted helminths (STH) with risk for humans due to its high infectivity and an important determinant of transmission is the inadequacy of water supplies and sanitation. The World Health Organization (WHO) recommends a limit equal to or lower than one parasitic helminth egg per liter, to reuse reclaimed water for unrestricted irrigation. We present two new protocols of DNA extraction from large volumes of reclaimed water. Quantitative PCR (qPCR) and digital PCR (dPCR) were able to detect low amounts of A. lumbricoides eggs. By using the first extraction protocol, which processes 500 mL of reclaimed water, qPCR can detect DNA concentrations as low as one A. lumbricoides egg equivalent, while dPCR can detect DNA concentrations as low as five A. lumbricoides egg equivalents. By using the second protocol, which processes 10 L of reclaimed water, qPCR was able to detect DNA concentrations equivalent to 20 A. lumbricoides eggs. This fact indicated the importance of developing new methodologies to detect helminth eggs with higher sensitivity and precision avoiding possible human infection risks.

Detection of helminth ova genera using in-situ biosynthesis of gold nanoparticles

“…A low infective dose combined with environmental hardiness and excretion of up to 200,000 ova per day in the faeces of infected hosts enhances the infectivity of Ascaris [3]. The use of raw and partially treated wastewater for agriculture is considered one of the major epidemiological factors for the prevalence of Ascaris infections [4]. Several studies have shown a significant relationship between Ascaris infection and exposure to treated and untreated wastewater [5].…”

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

“…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].…”

“…As a result of their environmental hardiness, the WHO recommends parasitic helminth ova as an indicator of sanitary risk and water quality parameters [19,20]. WHO recommends an upper limit of one helminth ova per litre for recycled water to be judged suitable for irrigation and public use [2,21,22]. Based on such recommendations, the modified Bailenger method was suggested as a universal method for the detection of one helminth ova per 10 litres of recycled water for urban, agricultural, industrial, or environmental use [23,24].…”

Development and evaluation of a loop-mediated isothermal amplification (LAMP) diagnostic test for detection of whipworm, Trichuris trichiura, in faecal samples

“…DNA-based diagnostic tests such as polymerase chain reaction (PCR) have proven to out-perform microscopy in their reliability to detect gastro-intestinal parasitic infections (Phuphisut et al ., 2014; Acosta Soto et al ., 2017). However, despite its high-throughput screening potential, PCR requires costly equipment (Kaisar et al ., 2017), and, therefore, has not been able to replace microscopy in the diagnosis of STH infections in large-scale epidemiological surveys or in disease control programs.…”