Postinfectious Syndromes and Long-Term Sequelae after Giardia Infections.

Giardiasis, caused by the parasite Giardia duodenalis, is a common infection throughout the world. Acute infections can be asymptomatic, cause mild gastrointestinal symptoms, or be associated with severe, prolonged diarrhea. Most Giardia infections are self-limiting; however, a subset of symptomatic and asymptomatic persons experience infection-associated chronic conditions that can affect multiple body systems. Those conditions include stunting and impaired cognitive function in children, irritable bowel syndrome, chronic fatigue, arthritis, and fibromyalgia, all of which can persist for months or years. Such conditions can impair daily functioning and quality of life; however, research has yet to fully elucidate underlying mechanisms, describe the prevalence, identify persons at increased risk, and develop effective treatment strategies. We synthesized what is known about giardiasis-associated chronic conditions and illnesses to improve recognition of those complications and ensure appropriate management that can improve the well-being of persons affected.