Genetic structure and epidemiology of Ascaris populations: Patterns of host affiliation in Guatemala

T. J C Anderson, M. E. Romero-Abal, J. Jaenike

Research output: Contribution to journalArticle

101 Citations (Scopus)

Abstract

In Guatemalan villages people commonly rear pigs, and both hosts may be infected with Ascaris. This study was designed to ask whether both humans and pigs are potential hosts in a single parasite transmission cycle in such villages, or alternatively, if there are two seprate transmission cycles, one involving pigs and one involving human hosts. Parasites were collected from both host species from locations in the north and south of Guatemala. Allelic variation in the nuclear genome of Ascaris was measured using enzyme electrophoresis, while mitochondrial DNA (mtDNA) sequence variation was quantified using restriction mapping. Low levels of enzyme polymorphism were found in Ascaris, but allele frequencies at two loci, mannose phosphate isomerase and esterase, suggest that there is little gene exchange between parasite populations from humans and pigs. MtDNA haplotypes fall into two distinct clusters which differ in sequence by 3-4%; the two clusters broadly correspond to worms collected from humans and those collected from pigs. However, some parasites collected from humans have mtDNA characteristic of the 'pig Ascaris' haplotype cluster, while some parasites collected from pigs have mtDNA characteristic of the 'human Ascaris' haplotype cluster. These shared haplotypes are unlikely to represent contemproary cross-infection events. Patterns of phylogenetic similarity and geographical distribution of these haplotypes suggest, instead, that they are the result of two historical introgressions of mtDNA between the two host-associated Ascaris populations. The results clearly demonstrate that Ascaris from humans and pigs are involved in separate transmission cycles in Guatemala.

Original languageEnglish (US)
Pages (from-to)319-334
Number of pages16
JournalParasitology
Volume107
Issue number3
StatePublished - 1993
Externally publishedYes

Fingerprint

Guatemala
Ascaris
Molecular Epidemiology
Genetic Structures
epidemiology
Swine
swine
Haplotypes
haplotypes
Parasites
Mitochondrial DNA
Population
parasites
mitochondrial DNA
villages
mannose-6-phosphate isomerase
enzyme polymorphism
Restriction Mapping
cross infection
restriction mapping

Keywords

  • Allozymes
  • Ascaris
  • Guatemala
  • Humans
  • Mitochondrial DNA
  • Pigs

ASJC Scopus subject areas

  • Immunology
  • Parasitology

Cite this

Anderson, T. J. C., Romero-Abal, M. E., & Jaenike, J. (1993). Genetic structure and epidemiology of Ascaris populations: Patterns of host affiliation in Guatemala. Parasitology, 107(3), 319-334.

Genetic structure and epidemiology of Ascaris populations : Patterns of host affiliation in Guatemala. / Anderson, T. J C; Romero-Abal, M. E.; Jaenike, J.

In: Parasitology, Vol. 107, No. 3, 1993, p. 319-334.

Research output: Contribution to journalArticle

Anderson, TJC, Romero-Abal, ME & Jaenike, J 1993, 'Genetic structure and epidemiology of Ascaris populations: Patterns of host affiliation in Guatemala', Parasitology, vol. 107, no. 3, pp. 319-334.
Anderson, T. J C ; Romero-Abal, M. E. ; Jaenike, J. / Genetic structure and epidemiology of Ascaris populations : Patterns of host affiliation in Guatemala. In: Parasitology. 1993 ; Vol. 107, No. 3. pp. 319-334.
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