Characterization of Giardia duodenalis isolates from a waterborne outbreak

J Infect Dis. 1993 Feb;167(2):431-40. doi: 10.1093/infdis/167.2.431.


Isolates were retrieved from drinking water and from animal and human sources associated with a waterborne outbreak of giardiasis. This is the first report of water-source and epidemic-associated Giardia isolates being adapted to in vitro propagation. Outbreak-associated, non-out-break-associated, and reference isolates were characterized using isoenzyme electrophoresis and pulsed-field gel electrophoresis (PFGE). All outbreak-associated and 2 other isolates were in one of eight zymodemes. The chromosomal complement of the outbreak-associated isolates was relatively homogeneous; this PFGE karyotype was distinguishable from other karyotypes. Overall results of both characterization methods were similar, although PFGE appears to be a more discriminating biotyping technique. Banding patterns of the outbreak-associated Giardia isolates remained the same even though the parasite passed through different hosts during the outbreak. Heterogeneity of isolates was also demonstrated for the first time within a single community not associated with the outbreak.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • British Columbia / epidemiology
  • Child, Preschool
  • Chromosome Banding
  • Disease Outbreaks*
  • Electrophoresis, Agar Gel
  • Giardia / classification*
  • Giardia / enzymology
  • Giardia / genetics
  • Giardia / isolation & purification
  • Giardiasis / epidemiology
  • Giardiasis / parasitology*
  • Humans
  • Infant
  • Infant, Newborn
  • Isoenzymes / analysis
  • Isoenzymes / genetics
  • Karyotyping
  • Middle Aged
  • Rodentia / parasitology*
  • Water Supply*


  • Isoenzymes