Giardia Infection
Giardia infection is caused by Giardia duodenalis, a flagellated protozoan parasite and the second most common cause of waterborne outbreaks worldwide. It is one of the most prevalent yet poorly understood parasitic organisms, with a long history of scientific interest since its discovery by Antony van Leeuwenhoek over 300 years ago. Giardia species are widespread, colonizing the intestines of diverse vertebrate hosts, and belong to the class Zoomastigophorea and order Diplomonadida. Despite longstanding debate about its evolutionary position, recent biochemical evidence suggests that Giardia's lack of mitochondria may be secondarily derived rather than ancestral, challenging earlier views of it as a 'missing link' between prokaryotes and eukaryotes.
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