Discovery of Giardia lamblia

Giardia lamblia is the intestinal parasite most frequently diagnosed by the public laboratories in the United States. Giardia lamblia holds the distinction of being the first protozoan parasite to be recognized.

It was described in a letter by van Leeuwenhoek of Delft, the Netherlands, to the Royal Society of Medicine in 1681 after he observed this parasite in his stool while trying to evaluate his own intermittence chronic diarrhea.

He made the important clinical observation that these ‘animalcules; could be found only in liquid stool, not in normal, formed stool.

The discovery was followed by more in-depth description of the organism by Alfred Mathieu Giard and Vilem Dusan Lambl almost two century later.

The first detailed description of Giardia was given by Vilem Dusan Lambl in 1859 for a flagellate in the human intestine which he named Cercomonas intestinalis.

In 1915 the species was renamed to Giardia lamblia by American zoologist Charles Wardell Stiles.

In 1925, Robert W. Hegner described Giardia felis from domestic cats in the United States, while Robert Deschiens in the same years described Giardia cati from cats in France.

In the early days,, Giardia was considered a harmless, free living protozoan. Despite the fact that Giard observed Giardia in stools of children with diarrhea he believed it was commensal, not responsible for the pathology.

In the mid twentieth century, Giardia was finally recognized as an agent pathogenic to humans and animals. 

By the late 1980s, Giardia lamblia had become the number one parasite-caused gastrointestinal disease in the United States and has become a major worldwide public health problem.
Discovery of Giardia lamblia