Preliminary testing of a rapid coupled methodology for quantitation/viability determination of helminth eggs in raw and treated wastewater

Victorica, Jorge de; Galván, Manuel González

doi:10.1016/s0043-1354(02)00477-3

Cited by 40 publications

(18 citation statements)

References 1 publication

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“…In order to test the viability of helminth eggs, we performed the Trypan Blue exclusion test, as described by (Victorica and Galvan 2003). An aliquot of 6 lL of the final pellet was placed on a slide along with 6 lL of Trypan Blue dye (0.1 %).…”

Section: Viability Of Helminth Eggsmentioning

confidence: 99%

Real scale environmental monitoring of zoonotic protozoa and helminth eggs in biosolid samples in Brazil

Bonatti

Franco

2014

J Parasit Dis

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Biosolid is the product of the activated sludge treatment system and its final disposition is subject of ongoing discussion as this residue can therefore harbor a great number and variety of pathogens. This study was aimed to (1) monitor the presence of Giardia and Cryptosporidium in biosolid samples from a treatment plant in Campinas, SP, Brazil, (2) observe Giardia cyst wall morphological integrity in treated samples using scanning electron microscopy (SEM) and (3) verify the presence and viability of helminth eggs. Cysts were present in 33.3 % of the samples, whereas oocysts were detected in 8.3 %. Viable Ascaris sp. Toxocara sp. and similar to Trichuris sp. eggs were found through the use of Mexican Official Norm. Results demonstrate the difficulties inherent in working with biosolid as factors such as temperature, ionic strength and pH influenced the recovery of cysts and oocysts. Pores and ruptures were not observed in cyst wall visualized by SEM following 45 days of exposure to sunlight, only minimal morphological changes. These observations emphasize both the importance of adequate treatment of sewage sludge and the need to develop appropriate techniques for the detection of Giardia and Cryptosporidium in this type of sample. This is the first time that a study was done in a real scale for biosolid samples in determining the presence of pathogenic protozoa as Giardia and Cryptosporidium in Brazil, and also observed minimal cyst wall damage after sunlight treatment.

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Section: Viability Of Helminth Eggsmentioning

confidence: 99%

Real scale environmental monitoring of zoonotic protozoa and helminth eggs in biosolid samples in Brazil

Bonatti

Franco

2014

J Parasit Dis

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“…however, there is not an universally accepted assay for determining viability of ova [16]. Staining techniques are rapid, as viable ova contain multiple layers that are impermeable, whereas ova that are permeable are assumed to be non-viable [20][21][22]. Potential infectivity is assumed at the moment ova remain impermeable.…”

Section: Introductionmentioning

confidence: 99%

“…Potential infectivity is assumed at the moment ova remain impermeable. however, some slightly permeable ova are stained with a light appearance and are assumed to be non-viable [20]. Without monitoring embryo development it is unknown whether slightly stained ova were actually viable, or if some non-viable ova remained impermeable.…”

Section: Introductionmentioning

confidence: 99%

A Method for Determining Ascaris Viability Based on Early-to-Late Stage In-Vitro Ova Development

Schmitz

Pearce‐Walker

Gerba³

et al. 2016

JRST

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This study suggests a new method for determining the viability of Ascaris spp. ova, based on in-vitro early-to-late stage development of ova. This method includes stages prior to larval development, providing an estimation of potential viability. After application of biosolids onto soil and exposure to 7°C, 22°C, or 37°C for 45 days, ova were microscopically distinguished as viable or non-viable according to progression through development categories. Results were compared to viability estimates from current methods that distinguish viable ova as motile larva. Results suggest conventional techniques underestimate viability, whereas the new method provides a more conservative approach.

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“…The womb and ovary were placed in 50 mL of physiological whey solution where they were opened to extract the helminth eggs. The optimal morphology and viability of the eggs of Ascaris suum were verified by microscopic observation according to Johnson et al [55] and by using the staining procedure applied by de Victorica and Galván [56], respectively. Helminth eggs were added to the 200 L wastewater tank, which was fed to the UASB reactors.…”

Section: Helminth Eggsmentioning

confidence: 99%

Helminth Egg Removal Capacity of UASB Reactors under Subtropical Conditions

Yaya-Beas

Ayala-Limaylla

Kujawa-Roeleveld

et al. 2015

Water

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This research was conducted to study the anaerobic sludge filtration capacity regarding helminth egg removal in upflow anaerobic sludge blanket (UASB) reactors. Two 25 L lab-scale UASB reactors were operated at an ambient temperature which varied between 17.1 and 28.6 °C. Ascaris suum egg was selected as the model egg considering its similarity in terms of size and morphology to Ascaris lumbricoides, a human pathogen. Ascaris suum eggs were obtained from female parasites of infected pigs. The anaerobic sludge filtration capacity was performed applying upflow velocities between 0.09 and 0.68 m·h −1. Three sludge bed heights in the range of 0.30-0.40 m, 0.50-0.60 m and 0.60-0.70 m were applied. These sludge bed heights corresponded to 19%-25%, 31%-38% and 38%-44% of the total reactor height, respectively. Under the mentioned conditions, the average helminth egg removal efficiency was reciprocally correlated to the imposed upflow velocity. The studied lab-scale reactors reported an average helminth egg removal between 34%-100%, 30%-91% and 34%-56%, when the sludge bed in the UASB reactor OPEN ACCESSWater 2015, 7 2403 was 19%-25%, 31%-38% and 38%-44% of the total reactor height, respectively. The decreased filtration capacity at increasing sludge bed heights might be likely related to biogas production and channeling formation. The average helminth egg removal efficiency in the control experiments performed without any sludge bed, by plain sedimentation, varied between 44% and 66%.

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Preliminary testing of a rapid coupled methodology for quantitation/viability determination of helminth eggs in raw and treated wastewater

Cited by 40 publications

References 1 publication

Real scale environmental monitoring of zoonotic protozoa and helminth eggs in biosolid samples in Brazil

Real scale environmental monitoring of zoonotic protozoa and helminth eggs in biosolid samples in Brazil

A Method for Determining Ascaris Viability Based on Early-to-Late Stage In-Vitro Ova Development

Helminth Egg Removal Capacity of UASB Reactors under Subtropical Conditions

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