Giardia duodenalis assemblage, clinical presentation and markers of intestinal inflammation in Brazilian children

Anita Kohli, Oluma Y. Bushen, Relana C. Pinkerton, Eric Houpt, Robert D. Newman, Cynthia L. Sears, Aldo A.M. Lima, Richard L. Guerrant

Research output: Contribution to journalArticlepeer-review

102 Scopus citations


Data on the relationship between the two genotypes of Giardia duodenalis that infect humans, assemblages A and B, their clinical presentation and intestinal inflammation are limited. We analyzed 108 stool samples previously collected for a diarrhoeal study among Brazilian children, representing 71 infections in 47 children. Assemblage B was most prevalent, accounting for 43/58 (74.1%) infections, while assemblage A accounted for 9/58 (15.5%) infections and 6/58 (10.3%) infections were mixed (contained both assemblage A and B). There was no significant difference in diarrhoeal symptoms experienced during assemblage A, B or mixed infections. Children with assemblage B demonstrated greater variability in G. duodenalis cyst shedding but at an overall greater level (n = 43, mean 3.6 × 105, range 5.3 × 102-2.5 × 106 cysts/ml) than children infected with assemblage A (n = 9, mean 1.4 × 105, range 1.5 × 104-4.6 × 105 cysts/ml; P = 0.009). Children with mixed infections shed more cysts (mean 8.3 × 105, range 3.1 × 104-2.8 × 106 cysts/ml) than children with assemblage A or B alone (P = 0.069 and P = 0.046 respectively). This higher rate of cyst shedding in children with assemblage B may promote its spread, accounting for its increased incidence. Additionally, second and third infections had decreasing faecal lactoferrin, suggesting some protection against severity, albeit not against infection, by prior infection.

Original languageEnglish (US)
Pages (from-to)718-725
Number of pages8
JournalTransactions of the Royal Society of Tropical Medicine and Hygiene
Issue number7
StatePublished - Jul 2008


  • Brazil
  • Cysts
  • Diarrhoea
  • Genotype
  • Giardia
  • Lactoferrin

ASJC Scopus subject areas

  • Parasitology
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases


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