Intestinal Protozoa: Giardia, Amebiasis, Cyclospora, Blastocystis Hominis, Dientamoeba Fragilis , and Cryptosporidium Parvum

This chapter focuses on common intestinal protozoal infections that occur among travelers. Giardia lamblia is among the commonest parasite infections acquired by humans and is the most frequently identified cause of prolonged travelers' diarrhea lasting at least 2 weeks. Entamoeba histolytica can cause either gastrointestinal symptoms or amebic liver abscess. Cyclospora typically causes watery diarrhea that, untreated, lasts up to 3 months. Blastocystis hominis is one of the most common organisms detected in stool specimens, but there is considerable controversy about whether it is pathogenic. Other protozoa briefly discussed include Dientamoeba fragilis and Cryptosporidium parvum.