Pig Ascaris: An important source of human ascariasis in China

Zhou, Chunhua; Li, Min; Yuan, Keng; Deng, Shoulong; Peng, Weidong

doi:10.1016/j.meegid.2012.04.016

Cited by 50 publications

(50 citation statements)

References 30 publications

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“…No examples of hybridization between pig and human worms were found in any location. In contrast, 7.8% of worms in China (n = 258) and 4% in Guatemala (n = 24) were identified as hybrids using 23 microsatellite markers, indicating the potential for exchange of genetic material between pig and human Ascaris populations [17, 18]. The fact that we did not find evidence of hybridization might reflect variations in transmission dynamics of Ascaris worms in different locations.…”

Section: Discussionmentioning

confidence: 65%

“…In Uganda, where around 18% of households keep pigs [44], 1 of 143 human worms (0.7%) was of pig origin and 1 of 56 pig worms (1.8%) was of human origin. In China, 13.9% of worms (n = 137) in humans were zoonotic and 0.8% of worms in pigs (n = 121) were anthroponotic [17]. The differences in level of zoonotic transmission between the 2 countries likely represent variations in farming practices, feces disposal, and human-pig contact.…”

Section: Discussionmentioning

confidence: 99%

“…The simulation was run again for each group separately, testing values of K from 1 to 10, using a burn-in of 100 000 and a run length of 1 000 000 to improve stability between runs. The presence of cross-transmission and hybrids between pig and human worms was investigated using STRUCTURE, NewHybrids [37], and BAPS [38], as described elsewhere [17, 18]. …”

Section: Methodsmentioning

confidence: 99%

“…Molecular studies have demonstrated that human Ascaris infections in developed countries are predominantly of pig origin [2–4, 12], whereas in developing countries human-to-human transmission predominates [13–16]. However, in China, 14% of human worms were derived from pigs (ie, were of zoonotic origin), indicating that cross-transmission in areas of endemicity may be more common than originally thought [17]. Hybrids between human and pig worms have been detected, indicating that mating can take place between Ascaris from the 2 host species [18].…”

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confidence: 99%

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Molecular Epidemiology of Ascariasis: A Global Perspective on the Transmission Dynamics of Ascaris in People and Pigs

Betson¹,

Nejsum²,

Bendall³

et al. 2014

The Journal of Infectious Diseases

122

119

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Background. The roundworm Ascaris lumbricoides infects 0.8 billion people worldwide, and Ascaris suum infects innumerable pigs across the globe. The extent of natural cross-transmission of Ascaris between pig and human hosts in different geographical settings is unknown, warranting investigation.Methods. Adult Ascaris organisms were obtained from humans and pigs in Europe, Africa, Asia, and Latin America. Barcodes were assigned to 536 parasites on the basis of sequence analysis of the mitochondrial cytochrome c oxidase I gene. Genotyping of 410 worms was also conducted using a panel of microsatellite markers. Phylogenetic, population genetic, and Bayesian assignment methods were used for analysis.Results. There was marked genetic segregation between worms originating from human hosts and those originating from pig hosts. However, human Ascaris infections in Europe were of pig origin, and there was evidence of cross-transmission between humans and pigs in Africa. Significant genetic differentiation exists between parasite populations from different countries, villages, and hosts.Conclusions. In conducting an analysis of variation within Ascaris populations from pig and human hosts across the globe, we demonstrate that cross-transmission takes place in developing and developed countries, contingent upon epidemiological potential and local phylogeography. Our results provide novel insights into the transmission dynamics and speciation of Ascaris worms from humans and pigs that are of importance for control programs.

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Section: Discussionmentioning

confidence: 65%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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Molecular Epidemiology of Ascariasis: A Global Perspective on the Transmission Dynamics of Ascaris in People and Pigs

Betson¹,

Nejsum²,

Bendall³

et al. 2014

The Journal of Infectious Diseases

122

119

View full text Add to dashboard Cite

show abstract

“…And yes, a number of studies have compared Ascaris isolates from pigs and humans and have identified close similarities in mitochondrial [4–6] and single nuclear markers (such as internal transcribed spacer [ITS] [5,7] and 18S rRNA [8]), including shared genotypes and haplotypes. It has been clearly established that Ascaris can cross infect hosts experimentally and in natural settings, as reviewed by Nejsum et al [9].…”

Section: Ascaris Taxonomy Is Contentiousmentioning

confidence: 99%