Soil Contamination with <i>Toxocara</i> Eggs in Public Schools in Rural Areas of Southern Thailand

Phasuk, Nonthapan; Kache, Ratee; Thongtup, Kanjana; Boonmuang, Saowalee; Punsawad, Chuchard

doi:10.1155/2020/9659640

Cited by 6 publications

(9 citation statements)

References 34 publications

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“…Humans acquire T. canis by accidentally ingesting infected eggs, which can be found in several public places [ 35 ]. A previous study conducted in rural areas of southern Thailand reported that the soil samples from public schools were contaminated with Toxocara eggs, especially that in the playgrounds; this correlated with our results as all dog owners reportedly allowed the dog to excrete outside the house (100%) [ 34 ]. This study suggests that people might be infected with T. canis in ways other than by caring for dogs and emphasizes the necessity of hand hygiene to prevent parasite eggs from entering the human body via the fecal–oral route.…”

Section: Discussionsupporting

confidence: 90%

“…This trend has also been reported in previous studies [ 31 , 32 ]. It has been hypothesized that males engage in more outdoor activities than females and, therefore, are more likely to be in contact with contaminated soil and dogs [ 33 , 34 ]. However, univariate and multivariate analyses demonstrated that sex was not significantly associated with seropositivity for anti- T.canis IgG antibodies in our study.…”

Section: Discussionmentioning

confidence: 99%

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Seroprevalence of anti-Toxocara canis antibodies and associated risk factors among dog owners in the rural community of Nakhon Si Thammarat province, southern Thailand

et al. 2022

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Background Human toxocariasis is a zoonotic parasitic disease caused by the Toxocara canis and T. cati nematodes larvae. Dog owners are at a higher risk of acquiring T. canis infection, and there is no available evidence regarding the seroprevalence of T. canis infection among dog owners in Thailand. Therefore, this study aimed to investigate the seroprevalence of T. canis infection and associated risk factors among dog owners in rural areas of Thailand. Methods A total of 132 dog owners, including 25 men and 107 women, were recruited for this study. Serum anti-T. canis IgG antibodies were detected using a commercial enzyme-linked immunosorbent assay (ELISA) kit, and information on risk factors was collected using a questionnaire. In addition, hematological parameters were analyzed by the auto hematology analyzer. Risk variables associated with T. canis infection were investigated using univariate and multivariate logistic regression models. Results The overall seroprevalence of T. canis was 76.5% (101/132). Men were more likely to be infected with T. canis than women. Univariate analysis revealed that dog owners who did not practice handwashing before meals (p = 0.005) or after contact with soil (p = 0.035) or dogs (p = 0.049) had a substantially higher risk of acquiring T. canis infection. After adjusting for confounders, not practicing handwashing before meals remained a significant risk factor for T. canis infection (p = 0.038). The mean number of eosinophils was significantly higher in the seropositive group than in the seronegative group. Conclusions This is the first serological report of T. canis infection among dog owners reflecting the high rate of T. canis seropositivity in rural areas of southern Thailand. This study also provides group-specific data concerning modifiable risk behaviors for more effective T. canis infection control and prevention strategies in Thailand.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Seroprevalence of anti-Toxocara canis antibodies and associated risk factors among dog owners in the rural community of Nakhon Si Thammarat province, southern Thailand

et al. 2022

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“…Soil is considered the primary source of Toxocara spp. transmission to humans, especially children [14]. Soil contamination by eggs of Toxocara spp.…”

Section: Discussionmentioning

confidence: 99%

Optimized DNA-based identification of Toxocara spp. eggs in soil and sand samples

et al. 2021

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Background Toxocara canis and Toxocara cati are globally distributed roundworms and causative agents of human toxocariasis, via ingestion of Toxocara eggs. Control of Toxocara infections is constrained by a lack of sensitive methods for screening of animal faeces and environmental samples potentially contaminated by Toxocara eggs. In this work, a pre-analytical method for efficient extraction of DNA from Toxocara eggs in environmental samples was set up using our previously validated T. canis- and T. cati-specific quantitative real-time polymerase chain reaction (qPCR). For this purpose, the influence of different methods for egg lysis, DNA extraction and purification for removal of PCR inhibitors were assessed on environmental samples. Methods To select the best egg disruption method, six protocols were compared on pure T. canis egg suspensions, including enzymatic lysis and thermal or mechanical disruption. Based on the selected best method, an analytical workflow was set up to compare two DNA extraction methods (FastDNA™ SPIN Kit for Soil versus DNeasy® PowerMax® Soil Kit) with an optional dilution and/or clean-up (Agencourt® AMPure®) step. This workflow was evaluated on 10-g soil and 10-g sand samples spiked with egg suspensions of T. canis (tenfold dilutions of 104 eggs in triplicate). The capacity of the different methods, used alone or in combination, to increase the ratio of positive tests was assessed. The resulting optimal workflow for processing spiked soil samples was then tested on environmental soil samples and compared with the conventional flotation-centrifugation and microscopic examination of Toxocara eggs. Results The most effective DNA extraction method for Toxocara eggs in soil samples consisted in the combination of mechanical lysis of eggs using beads, followed by DNA extraction with the DNeasy® PowerMax® Soil Kit, and completed with an additional DNA clean-up step with AMPure® beads and a sample DNA dilution (1:10). This workflow exhibited a limit of detection of 4 and 46 T.canis eggs in 10-g sand and 10-g soil samples, respectively. Conclusions The pre-analytical flow process developed here combined with qPCR represents an improved, potentially automatable, and cost-effective method for the surveillance of Toxocara contamination in the environment. Graphical Abstract

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“…Soil is considered the primary source of Toxocara transmission to humans, especially children [14]. Soil contamination by eggs of Toxocara spp.…”

Section: Discussionmentioning

confidence: 99%

Optimized DNA-based Identification of Toxocara spp. Egg in Difficult Matrices: A Case for Specific and Sensitive Identification of Geohelminth Eggs

Jarosz

Durant

Irenge

et al. 2021

Preprint

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BackgroundToxocara canis (T. canis) and Toxocara cati (T. cati) are worldwide-distributed roundworms of canids and felids and causative agents of human toxocarosis, via ingestion of Toxocara eggs disseminated in the environment. Control of Toxocara infections is constrained by the lack of sensitive methods for screening of animal feces and environmental samples potentially contaminated by Toxocara eggs. We previously developed a quantitative duplex real-time PCR (qPCR) for sensitive and specific detection of T. canis and T. cati. In this work, a pre-analytical method for efficient extraction of DNA from Toxocara eggs present in environmental samples was set up. For this purpose, the influence of different methods for eggs lysis, DNA extraction and purification for removal of PCR inhibitors were assessed on environmental samples.MethodsSoil and sand (10g) samples were spiked with egg suspensions of T. canis. DNA was extracted from Toxocara eggs, using different DNA extraction kits (FastDNA™ SPIN Kit for Soil and DNeasy® PowerMax® Soil Kit), and an additional clean-up step (Agencourt® AMPure®). The efficiency of the above-developed process was compared with the conventional flotation-centrifugation and observation of Toxocara eggs under light microscopy.ResultsThe most effective DNA extraction method for Toxocara eggs in soil samples consisted in the combination of mechanical lysis of eggs using beads, DNA extraction with the DNeasy® PowerMax® Soil Kit and an additional DNA clean-up step with AMPure® beads. with a limit of detection of 6 eggs of T. canis spiked in 10 g of soil with a probability of 97%.ConclusionThe pre-analytical flow process developed here combined with qPCR represents an improved method for the surveillance of Toxocara contamination in the environment.

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Soil Contamination with Toxocara Eggs in Public Schools in Rural Areas of Southern Thailand

Cited by 6 publications

References 34 publications

Seroprevalence of anti-Toxocara canis antibodies and associated risk factors among dog owners in the rural community of Nakhon Si Thammarat province, southern Thailand

Seroprevalence of anti-Toxocara canis antibodies and associated risk factors among dog owners in the rural community of Nakhon Si Thammarat province, southern Thailand

Optimized DNA-based identification of Toxocara spp. eggs in soil and sand samples

Optimized DNA-based Identification of Toxocara spp. Egg in Difficult Matrices: A Case for Specific and Sensitive Identification of Geohelminth Eggs

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