A modified assay for the enumeration of ascaris eggs in fresh raw sewage

Esmaeil Shahsavari,Jonathan Schmidt,Arturo Aburto-Medina,Basma Khallaf,Vivek Balakrishnan,Nicholas D Crosbie,Aravind Surapaneni,Andrew S Ball

doi:10.1016/j.mex.2017.04.001

Esmaeil Shahsavari, Jonathan Schmidt + Show 6 more

Open Access

https://doi.org/10.1016/j.mex.2017.04.001

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Abstract

Soil-transmitted helminths (STHs) pose a significant public health problem, infecting approximately 2 billion people globally. Despite relatively low prevalence in developed countries, the removal of STHs from wastewater remains crucial to allow the safe use of biosolids or recycled water for agriculture. Wastewater helminth egg count data can contribute to an assessment of the need for, or success of, a parasite management program. Although the World Health Organisation (WHO) has recommended a standard method for counting helminth eggs in raw sewage based on the method of Bailenger (Ayres et al., 1996), the method generally results in low percentage egg recoveries. Given the importance of determining the presence of STHs, it is essential to develop novel techniques that optimise the recovery rate of eggs from raw sewage. In the present study:•The method described by Bowman et al. (2003) was optimized for the concentration and enumeration of helminth eggs in raw sewage from municipal sewage treatment plants.•The method is simple and reproducible and recovers a greater percentage of helminth eggs compared to the WHO method.

Highlights

Transfer and combine the supernatant containing the helminth eggs to the centrifuge tube in step 18. [34_TD$IF]22
Raw sewage samples were collected from different sewage treatment plants in Victoria, Australia and 1. Allow the raw sewage (1 L) homogenous samples were prepared for processing
Samples were processed in parallel, 1) following the modified Bowman method with the addition of 100 mL of the stock A. suum egg preparation, 2) following the modified Bowman method without the addition of

Summary

Method Article

A modified assay for the enumeration of ascaris eggs in fresh raw sewage Esmaeil Shahsavaria, [14_TD$IF]Jonathan Schmidtb,d,*, Arturo Aburto-Medinaa, Basma Khallafa, Vivek Balakrishnana, [15_TD$IF]Nicholas D. Despite relatively low prevalence in developed countries, the removal of STHs from wastewater remains crucial to allow the safe [2_TD$IF]use of biosolids or recycled water for agriculture.[23_TD$IF] Wastewater helminth egg count data can contribute to an assessment of the need for, or success of, a parasite management program. The World Health Organisation (WHO) has recommended a standard method for counting helminth eggs in raw sewage based on the method of Bailenger (Ayres et al, 1996), the method generally results in low percentage egg recoveries. Given the importance of determining the presence of STHs, it is essential to develop novel techniques that optimise the recovery rate of eggs from raw sewage. ARTICLE INFO Keywords: Helminths, Ascaris suum, Recovery rate, Wastewater Article history: Received 9 December 2016; Accepted 21 April 2017; Available online 1 May 2017

Method details

Method validation