title: Advances in understanding Giardia: determinants and mechanisms of chronic sequelae.
abstract: Giardia lamblia is a flagellated protozoan that is the most common cause of intestinal parasitic infection in children living in resource-limited settings. The pathogenicity of Giardia has been debated since the parasite was first identified, and clinical outcomes vary across studies. Among recent perplexing findings are diametrically opposed associations between Giardia and acute versus persistent diarrhea and a poorly understood potential for long-term sequelae, including impaired child growth and cognitive development. The mechanisms driving these protean clinical outcomes remain elusive, but recent advances suggest that variability in Giardia strains, host nutritional status, the composition of microbiota, co-infecting enteropathogens, host genetically determined mucosal immune responses, and immune modulation by Giardia are all relevant factors influencing disease manifestations after Giardia infection.
authors.affiliation: Division of Infectious Diseases and International Health, University of Virginia Box 801340, Charlottesville, VA 22908 USA.
authors.forename: Luther A
authors.initials: LA
authors.lastname: Bartelt
authors.affiliation: Division of Gastroenterology, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel Hill Campus Box 7032, Chapel Hill, NC 27599-7032 USA.
authors.forename: R Balfour
authors.initials: RB
authors.lastname: Sartor