Detecting and enumerating soil-transmitted helminth eggs in soil: New method development and results from field testing in Kenya and Bangladesh

Steinbaum, Lauren; Kwong, Laura H.; Ercümen, Ayşe; Negash, Makeda S.; Lovely, Amira J.; Njenga, Sammy M.; Boehm, Alexandria B.; Pickering, Amy J.; Nelson, Kara L.

doi:10.1371/journal.pntd.0005522

Cited by 62 publications

(88 citation statements)

References 38 publications

(48 reference statements)

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“…Therefore, the distribution of eggs in the soil (Ascaris, Trichuris) in Bangladesh was 78%, and 37% in Kenya, with the average egg concen-tration in soil 0.59 and 0.15 eggs/g, respectively. The distribution of eggs of helminths in the soil was significantly higher in Bangladesh than in Kenya (Steinbaum et al, 2017). Other studies have shown that of 1,480 soil samples, 460 (31%) were positive for the presence of eggs of helminths.…”

Section: Discussionmentioning

confidence: 75%

“…The invasion of parasites, when discharged with feces into the environment, pollutes the soil, water, vegetation and can persist for a long time (Paller & de Chavez, 2014;Tun et al, 2015;Dolbin & Khayrullin, 2017). Exogenous forms of helminths in the environment are represented by eggs and free-living invasive larvae (Blaszkowska et al, 2011;Mohd Zain et al, 2013;Steinbaum et al, 2017), posing a serious hygiene problem (Amadi & Uttah, 2010;Shalaby et al, 2010;Ngui et al, 2012). The main goal of veterinary sanitation is prevention of infectious and parasitic diseases of humans and animals, reduction of ecological pollution of the environment, including water, soils, feed and livestock products, elimination of epizootic outbreaks by means of disinfection, disinfestation, disinsection and deratization (Backhans & Fellström, 2012;Paliy et al, 2016;Spanu et al, 2016;Paliy et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Contamination of animal-keeping premises with eggs of parasitic worms

et al. 2018

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Today, one of the important problems in the cultivation and maintenance of agricultural and domestic animals, both in industrial and private farms, is the spread of ecto- and endoparasites, which cause a significant decline in animal productivity, endanger their health and cause economic losses. The study of the level of distribution and conducting of diagnostic studies on parasitoses of animals in farms with different production orientation is an important and integral part of the overall complex of preventive and health-improving measures. The research was carried out during 2007–2017 in livestock enterprises of Kharkiv Oblast. As a part of the research work, 540 samples were collected from livestock farms, of which 180 were from the premises for keeping pigs, 100 from premises for keeping sheep, 120 from premises for keeping cattle, 80 from premises for dogs and 60 – from the surrounding territories of the livestock enterprises. We found that the objects of livestock rearing (pig complex, sheep farm, dairy farm, cynological center) in Kharkiv Oblast have a significant level of sanitary contamination with exogenous forms of helminths (21.7–45.6%) and the soil of the territories (20.0–36.6%). From samples taken from premises for pigs, eggs of four morphotypes were isolated (Ascaris suum – 5.3%, Trichuris suis – 14.6%, Oesophagostomum dentatum – 60.6%, Strongyloides ransomi – 19.4%), from premises for sheep – three morphotypes (Dicrocoelium lanceatum – 3.8%, Trichuris ovis – 29.3%, Strongylata spp. – 46.9%), from premises for cows – three morphotypes (Neoascaris vitulorum – 2.7%, Trichuris skrjabini – 12.9%, Strongylata spp. – 34.5%), premises for dogs – four morphotypes (Toxocara canis – 6.1%, Toxascaris leonina – 5.4%, Trichuris vulpis – 20.6%, Ancylostoma caninum – 17.5%). It should be noted that the places most contaminated with eggs of helminths were manure gutters (100%) and the floor of livestock buildings (50.0–86.7%). It has also been determined that, in the conditions of the cynological center, the Musca domestica was the source of environmental contamination with exogenous forms of Toxocara canis and Trichuris vulpis, and that the Muscina stabulans and Stomoxys calcitrans can be the source of spread of larvae of Ancylostoma caninum and eggs of Trichuris vulpis respectively.

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Section: Discussionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Contamination of animal-keeping premises with eggs of parasitic worms

et al. 2018

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“…Enteric parasites are transmitted through ingestion or skin contact with infectious stages in soil, water and food, in a fecally-contaminated environment. Most transmission is considered to occur around or within households [9,10]. Here, using a sensitive and specific molecular method to detect a range of intestinal parasites, we show for the first time, a potential new source of transmission of these parasites from within the household, especially in bed dust.…”

Section: Discussionmentioning

confidence: 83%

“…Previous studies have sampled for presence of infectious parasite stages as sources of transmission around households including latrines [6,7] and within houses [8][9][10] but none to our knowledge have used sensitive molecular methods to detect specific parasite DNA.…”

Section: Introductionmentioning

confidence: 99%

Detection of enteric parasite DNA in household and bed dust samples: potential for infection transmission

et al. 2020

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Background: Enteric parasites are transmitted in households but few studies have sampled inside households for parasites and none have used sensitive molecular methods. Methods: We collected bed and living room dust samples from households of children participating in a clinical trial of anthelmintic treatment in rural coastal Ecuador. Dust was examined for presence of DNA specific for 11 enteric parasites (Ascaris lumbricoides, Trichuris trichiura, Ancylostoma duodenale, Necator americanus, Strongyloides stercoralis, Toxocara canis and T. cati, Giardia lamblia, Blastocystis hominis, Cryptosporidium spp., and Entamoeba histolytica) by quantitative PCR (qPCR). Results: Of the 38 households sampled, 37 had positive dust for at least one parasite and up to 8 parasites were detected in single samples. Positivity was greatest for B. hominis (79% of household samples) indicating a high level of environmental fecal contamination. Dust positivity rates for individual pathogens were: S. stercoralis (52%), A. lumbricoides (39%), G. lamblia (39%), Toxocara spp. (42%), hookworm (18%) and T. trichiura (8%). DNA for Cryptosporidium spp. and E. histolytica was not detected. Bed dust was more frequently positive than floor samples for all parasites detected. Positivity for A. lumbricoides DNA in bed (adjusted OR: 10.0, 95% CI: 2.0-50.1) but not floor dust (adjusted OR: 3.6, 95% CI: 0.3-37.9) was significantly associated with active infections in children. Conclusions: To our knowledge, this is the first use of qPCR on environmental samples to detect a wide range of enteric pathogen DNA. Our results indicate widespread contamination of households with parasite DNA and raise the possibility that beds, under conditions of overcrowding in a humid tropical setting, may be a source of transmission.

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“…Diagnostic tests with greater specificity and sensitivity are crucial to successfully detect the presence of Ascaris ova in recycled water prior to release for public use [53]. Such a test will also help to monitor the transmission of ascariasis in endemic and low resource setting areas.…”

Section: Discussionmentioning

confidence: 99%

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

Ravindran

Khallaf

Surapaneni

et al. 2020

Water

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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.

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Detecting and enumerating soil-transmitted helminth eggs in soil: New method development and results from field testing in Kenya and Bangladesh

Cited by 62 publications

References 38 publications

Contamination of animal-keeping premises with eggs of parasitic worms

Contamination of animal-keeping premises with eggs of parasitic worms

Detection of enteric parasite DNA in household and bed dust samples: potential for infection transmission

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

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