Scanning electron micrograph (SEM) depicting a Giardia lamblia protozoan undergoing binary fission, creating what appears to be a microscopic “heart.” This flagellated protozoan parasite inhabits and reproduces in the lumen of the small intestine and is responsible for the diarrheal infection giardiasis.
Giardia intestinalis is a protozoan flagellate (Diplomonadida). This protozoan was initially named Cercomonas intestinalis by Lambl in 1859. It was renamed Giardia lamblia by Stiles in 1915 in honor of Professor A. Giard of Paris and Dr. F. Lambl of Prague. However, many consider the name, Giardia intestinalis, to be the correct name for this protozoan. The International Commission on Zoological Nomenclature is reviewing this issue.