TY - JOUR

T1 - Molecular epidemiology of ascariasis

T2 - a global perspective on the transmission dynamics of Ascaris in people and pigs

AU - Betson, Martha

AU - Nejsum, Peter

AU - Bendall, Richard P.

AU - Deb, Rinki M.

AU - Stothard, J. Russell

N1 - © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.

PY - 2014

Y1 - 2014

N2 - 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.

AB - 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.

U2 - 10.1093/infdis/jiu193

DO - 10.1093/infdis/jiu193

M3 - Journal article

C2 - 24688073

VL - 210

SP - 932

EP - 941

JO - Journal of Infectious Diseases

JF - Journal of Infectious Diseases

SN - 0022-1899

IS - 6

ER -