Comparison of Techniques for the Detection of Helminth Ova in Drinking Water and Wastewater

Maya, C.; Jiménez, B.; Schwartzbrod, J.

doi:10.2175/106143005x89571

Cited by 28 publications

(38 citation statements)

References 7 publications

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“…The results indicated that the recovery rate of Method C was as high as 50% for treated wastewater and 12% for raw wastewater samples. This is comparable to a 26% recovery rate of Ascaris from treated wastewater reported by Maya et al, (2006), and 9-49% recovery rate of Cryptosporidium oocysts and Giardia cysts from environmental waters reported by Nieminski et al, (1995) using a similar methodology. One drawback of this method is the potential clogging of the sieve with large solid wastewater particles.…”

Section: Discussionsupporting

confidence: 87%

“…Various methods have been used previously to recover hookworm ova from wastewater matrices with variable degrees of success (Bowman et al, 2003;McCuin and Clancy, 2005;Maya et al, 2006;Ensink et al, 2008). In light of this, several rapid concentration methods for the recovery of hookworm ova from wastewater matrices including sludge samples were evaluated.…”

Section: Discussionmentioning

confidence: 99%

“…The concentration method developed by the US EPA has been the most commonly used to recover helminths ova from wastewater and sludge samples (US EPA, 1999). The recovery rate of this method can range from 65-74% from wastewater samples (Maya et al, 2006). This method, however, is laborious and time-consuming due to the requirement of multiple steps of washing and concentrating the samples (Ferguson et al, 2004).…”

Section: Isolation and Concentration Of Ovamentioning

confidence: 99%

“…Several methods have also been used to recover various microorganisms including ova from water and soil samples. Those include centrifugation (Whitmore and Carrington, 1993;Higgins et al, 2003), hollow-fiber ultrafiltration (HFUF) (Simmons et al, 2001;Ferguson et al, 2004;Hill et al, 2005;Hill et al, 2007), filtration (Nieminski et al, 1995;Maya et al, 2006;Alli et al, 2011), and flotation (US EPA, 1999;Bowman et al, 2003;de Victorica and Galván, 2003;Bastos et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…This method, however, is laborious and time-consuming due to the requirement of multiple steps of blending, washing, settling, filtering, floating and centrifuging (Ferguson et al, 2004). The recovery rate of this method is reported as being suboptimal and variable depending on the matrices (65-74% and 26-82% from raw wastewater and sludge) (Bowman et al, 2003;Maya et al, 2006;Bastos et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Detection of viable hookworm ova from wastewater and sludge

Gyawali¹

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Infectious helminths are a worldwide major public health problem. In terms of morbidity, approximately 3 × 10 9 people are infected by soil-transmitted helminths (STHs) influencing rates of malnutrition and failure to thrive. All of this increases the global disease burden (GDB) by up to 5.9 × 10 6 Daily Adjusted Life Years (DALYs). Helminth infections are more often seen as a major public health issue for developing countries however, concerns have been expressed in many of the developed nations because of the increased use of treated wastewater and sludge with no clear way of knowing the infection potential that can be attributed from such water.Guidelines have been established to minimise the potential public health risk associated with wastewater and sludge reuse. For example, the WHO guideline specified ≤ 1 ova (Ascaris lumbricoides) per L liquid (wastewater) or 4 g dry solid (sludge) for unrestricted use. Various wastewater treatment processes have been recommended to remove the helminths ova from wastewater depending upon its reuse. However, detection methods used to quantify viable helminths ova from wastewater has limitations. Therefore there is always a potential public health risk associated with reuse of wastewater and sludge.In this research, a real-time PCR method was developed. The new PCR method is rapid and specific. The method was found to be able to detect less than one ovum in one litre treated wastewater and approximately four ova in one litre raw wastewater and ~ 4 g sludge.The real-time PCR method was modified to a quantitative PCR (qPCR) method and further used to quantify hookworm ova from wastewater and sludge. The qPCR had estimated an average of 1.1, 8.6 and 67.3 ova for treated wastewater that was seeded with 1, 10 and 100 ova, respectively. The gene copy numbers obtained for 1, 10 and 100 ova by qPCR varied significantly (P < 0.05) within the tested samples indicating that absolute quantification of ova may not be accurate. Despite the difficulty quantifying accurate numbers of hookworm ova, the lower limit of quantification (LLOQ) of the qPCR method was 30 gene copies. This was a lot less than the gene copies produced by one ovum. Therefore, the qPCR method has potential to use for complying with wastewater guidelines.. iiAlthough the overall aim of this research was to develop a sensitive and specific method for quantitative detection of viable hookworm ova from wastewater, the importance of recovering the ova from wastewater and sludge samples for accurate detection was identified. While determining appropriate recovery rates was not an aim of this research, a suitable method that could be used to standardise research outcomes for further study was established. Therefore, ova recovery rate by different rapid methods was evaluated for further experiments. The result indicated that the ova recovery rate was higher for the treated wastewater (0.2 -50%) than the raw wastewater (0.3 -35%) and sludge (0.02 -4.7%) samples. A significant difference (P < 0.05) was observed between...

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Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Isolation and Concentration Of Ovamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Detection of viable hookworm ova from wastewater and sludge

Gyawali¹

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Detection of Microbiological Content in Water as Indicator of Its Ecological State − Mini‐Review

Besarab

Новик

2016

CLEAN Soil Air Water

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Intense anthropogenic pressure on the native media causing grave ecological problems such as deficiency of drinking water, shift of natural evolution of ecosystems due to species extinction, emphasizes the need of accurate analytical systems for continuous environmental monitoring. Microorganisms as simple sensitive living units conducting nutrient metabolic cycles in the environment are applicable for proper assessment of ambient media state. The paper will review modes of microbial contribution in indication and will list important and standard micro-indicators of water pollution. The article will describe up-to-date direct methods of pollutant detection and indirect indicator-recognition techniques. The peculiarities and requirements of water quality monitoring correlated with high dynamics and mobility of aqueous media will be discussed.

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Quantitative detection of viable helminth ova from raw wastewater, human feces, and environmental soil samples using novel PMA-qPCR methods

Gyawali

Ahmed

Sidhu

et al. 2016

Environ Sci Pollut Res

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In this study, we have evaluated the efficacy of propidium monoazide quantitative polymerase chain reaction (PMA-qPCR) to differentiate between viable and non-viable Ancylostoma caninum ova. The newly developed method was validated using raw wastewater seeded with known numbers of A. caninum ova. Results of this study confirmed that PMA-qPCR has resulted in average of 88 % reduction (P < 0.05) in gene copy numbers for 50 % viable +50 % non-viable when compared with 100 % viable ova. A reduction of 100 % in gene copies was observed for 100 % non-viable ova when compared with 100 % viable ova. Similar reductions (79-80 %) in gene copies were observed for A. caninum ova-seeded raw wastewater samples (n = 18) collected from wastewater treatment plants (WWTPs) A and B. The newly developed PMA-qPCR method was applied to determine the viable ova of different helminths (A. caninum, A. duodenale, Necator americanus and Ascaris lumbricoides) in raw wastewater, human fecal and soil samples. None of the unseeded wastewater samples were positive for the above-mentioned helminths. N. americanus and A. lumbricoides ova were found in unseeded human fecal and soil samples. For the unseeded human fecal samples (1 g), an average gene copy concentration obtained from qPCR and PMA-qPCR was found to be similar (6.8 × 10(5) ± 6.4 × 10(5) and 6.3 × 10(5) ± 4.7 × 10(5)) indicating the presence of viable N. americanus ova. Among the 24 unseeded soil samples tested, only one was positive for A. lumbricoides. The mean gene copy concentration in the positively identified soil sample was 1.0 × 10(5) ± 1.5 × 10(4) (determined by qPCR) compared to 4.9 × 10(4) ± 3.7 × 10(3) (determined by PMA-qPCR). The newly developed PMA-qPCR methods were able to detect viable helminth ova from wastewater and soil samples and could be adapted for health risk assessment.

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Comparison of Techniques for the Detection of Helminth Ova in Drinking Water and Wastewater

Cited by 28 publications

References 7 publications

Detection of viable hookworm ova from wastewater and sludge

Detection of viable hookworm ova from wastewater and sludge

Detection of Microbiological Content in Water as Indicator of Its Ecological State − Mini‐Review

Quantitative detection of viable helminth ova from raw wastewater, human feces, and environmental soil samples using novel PMA-qPCR methods

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