Anthropozoonotic Giardia duodenalis genotype (assemblage) a infections in habitats of free-ranging human-habituated gorillas, Uganda

Thaddeus K. Graczyk, John Bosco-Nizeyi, B. Ssebide, R. C.Andrew Thompson, Carolyn Read, Michael R. Cranfield

Research output: Contribution to journalArticlepeer-review

103 Scopus citations


To facilitate ecotourism and research, free-ranging mountain gorillas of Uganda have been habituated to humans. Testing of fecal samples of gorillas (n = 100), people sharing gorilla habitats (n = 62), and local pre- and postweaned cattle (n = 50) having access to these habitats with fluorescein isothiocyanate-conjugated monoclonal antibodies revealed Giardia duodenalis cysts at prevalences of 2.5, and 10%, respectively. The identification of G. duodenalis was confirmed by fluorescent in situ hybridization with 2 species-specific 18-bp oligonucleotide probes conjugated to hexachlorinated 6-carboxyfluorescein. The mean pathogen concentration was 2.5, 2.8, and 0.2 × 104 cysts/g of the gorilla, people, and cattle feces, respectively. All cyst isolates aligned with genotype (assemblage) A, as confirmed by polymerase chain reaction amplification and sequencing of a 130-bp region near the 5′ end of the small subunit-ribosomal RNA gene. A single genotype (assemblage) A recovered from 3 genetically distant but geographically united host groups indicates anthropozoonotic transmission of G. duodenalis. A large percentage of the local community does not follow park regulations regarding the disposal of their fecal waste, as self-reported in a questionnaire. This genotype may have been introduced into gorilla populations through habituation activities and may have then been sustained in their habitats by anthropozoonotic transmission.

Original languageEnglish (US)
Pages (from-to)905-909
Number of pages5
JournalJournal of Parasitology
Issue number5
StatePublished - Oct 2002

ASJC Scopus subject areas

  • Parasitology
  • Ecology, Evolution, Behavior and Systematics


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