Distributions and Predisposition: People and Pigs

Holland, Celia V.; Boes, Jaap

doi:10.1007/0-306-47383-6_1

Cited by 11 publications

(13 citation statements)

References 66 publications

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“…Also, susceptibility to cross infection may be increased in hosts compromised by nutritional and/or environmental stresses, and/or concurrent infections with other pathogenic organisms (cf. [48,49]). Parasite factors may include differences in the overall genetic make-up, physiology and/or biochemistry between closely related genotypes or species of Ascaris.…”

Section: Discussionmentioning

confidence: 96%

Molecular epidemiological investigation of Ascaris genotypes in China based on single‐strand conformation polymorphism analysis of ribosomal DNA

Peng¹,

Yuan²,

Zhou³

et al. 2003

Electrophoresis

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Using a single-strand conformation polymorphism-based approach, we investigated nucleotide variation in part of the first internal transcribed spacer (pITS-1) of nuclear ribosomal DNA within and among a large number of Ascaris individuals from humans and pigs from six endemic regions in China, and examined the frequency of the different genotypes of Ascaris in relation to host species and geographical origin. Five different SSCP genotypes (G1-G5) were recorded for human Ascaris (n = 486), of which three (genotypes G1-G3) were detected for pig Ascaris (n = 329). Of the five Ascaris genotypes detected, genotype G1 predominantly infected humans (approximately 63-74%) whereas genotype G3 infected mainly pigs (approximately 79-86%), indicating that each of these genotypes has a particular host affiliation. In contrast, the frequencies of the other three genotypes was substantially lower for each of the two host species. The findings also suggested that the rate of cross infection of Ascaris between humans and pigs is relatively low and that gene flow between the predominant genotypes is limited, consistent with previous proposals for endemic regions in other countries. While the nature and extent of nucleotide variation in the pITS-1 (and the proposal of host affiliated Ascaris populations) may relate to "introgression" or "lineage sorting and retention of ancentral polymorphism", other explanations are possible. Evidence of multiple pITS-1 sequence types in some Ascaris individuals representing particular genotypes (e.g., G2 and G5) may suggest hybridization between human- and pig-affiliated Ascaris. This aspect and the species status of Ascaris (from each host species) warrant future experimental testing, employing the pig/Ascaris model and the present electrophoretic approach.*

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Section: Discussionmentioning

confidence: 96%

Molecular epidemiological investigation of Ascaris genotypes in China based on single‐strand conformation polymorphism analysis of ribosomal DNA

Peng¹,

Yuan²,

Zhou³

et al. 2003

Electrophoresis

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“…In nonendemic regions, the human host may not have been exposed previously to pig Ascaris, whereas in endemic regions (possibly due to traditions of using pig excrement as a fertilizer) humans may have adequate immunological exposure to dead or viable porcine Ascaris eggs, thus blocking or inhibiting cross-infection. In addition, susceptibility to cross-infection may be increased in hosts compromised by environmental or nutritional stresses, and/or concurrent infections with other infectious agents [49,50]. Parasite factors may include differences in the genetic make-up, physiology, and/or biochemistry between closely related genotypes or species of Ascaris.…”

Section: H1-b202 T C a T C T G C A G G C T A T A T T A C G A G T T T mentioning

confidence: 97%

Mutation scanning-coupled analysis of haplotypic variability in mitochondrial DNA regions reveals low gene flow between human and porcineAscaris in endemic regions of China

Peng

Yuan

et al. 2005

Electrophoresis

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Haplotypic variation within and among the Ascaris populations representing six provinces in China was investigated. Mitochondrial DNA regions in the cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes were amplified by PCR from total genomic DNA samples (n > 720) from Ascaris individuals from humans and pigs, and subjected to mutation scanning and subsequent selective sequencing. For the cox1, ten different electrophoretic profiles were recorded for human Ascaris, and the same number for pig Ascaris, one of them being common to both host species. For the nad1, 11 different profiles were detected for human Ascaris, and 15 for pig Ascaris. Having defined all haplotypes (20 for pcox1 and 26 for pnad1) by sequencing, their frequencies were estimated in each of the two host species and each of the six provinces. For each mitochondrial region, the frequency of the different haplotypes varied considerably, depending on host species and geographical origin. Analysis of the sequence data (representing all haplotypes for each mitochondrial locus) by F-statistics indicated restricted gene flow between human Ascaris and pig Ascaris, and supported the conclusions from previous molecular epidemiological investigations that pigs are not a significant source of Ascaris infection in humans in endemic regions.

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“…Nematode worms of the genera Ascaris and Trichuris are the most prevalent helminth infections in humans and pigs worldwide (Holland & Boes, 2002). In both cases, the worms that infect pigs and humans are closely related and difficult to distinguish morphologically owing to a lack of discrete characters.…”

Section: Introductionmentioning

confidence: 99%

Assessing the zoonotic potential ofAscaris suumandTrichuris suis: looking to the future from an analysis of the past

et al. 2012

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The two geohelminths, Ascaris lumbricoides and Trichuris trichiura, infect more than a billion people worldwide but are only reported sporadically in the developed part of the world. In contrast, the closely related species A. suum and T. suis in pigs have a truly global distribution, with infected pigs found in most production systems. In areas where pigs and humans live in close proximity or where pig manure is used as fertilizer on vegetables for human consumption, there is a potential risk of cross-infections. We therefore review this relationship between Ascaris and Trichuris in the human and pig host, with special focus on recent evidence concerning the zoonotic potential of these parasites, and identify some open questions for future research.

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Distributions and Predisposition: People and Pigs

Cited by 11 publications

References 66 publications

Molecular epidemiological investigation of Ascaris genotypes in China based on single‐strand conformation polymorphism analysis of ribosomal DNA

Molecular epidemiological investigation of Ascaris genotypes in China based on single‐strand conformation polymorphism analysis of ribosomal DNA

Mutation scanning-coupled analysis of haplotypic variability in mitochondrial DNA regions reveals low gene flow between human and porcineAscaris in endemic regions of China

Assessing the zoonotic potential ofAscaris suumandTrichuris suis: looking to the future from an analysis of the past

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