Protista; not a prokaryote, but not an animal either. Can´t tell you much else as I find Protista a very vague and unhelpful group myself ^^;
The definition of giardia is any flagellate of the genus Giardia, parasitic in the intestines of vertebrates.
Giardia lamblia cause a disease called Giardiasis. According to PubMedHealth, the disease is marked by abdominal pain; diarrhea; gas or bloating; headache; loss of appetite; low-grade fever; nausea; swollen or distended abdomen or vomiting.
The disease is caused by a protozoa that is passed through untreated drinking water. Around 80% of cases go away without medical treatment. The others can be treated by anti-infection agents (which kill off the protozoa.)
The most serious effect of the disease is dehydration (from diarrhea.) It's a common problem in places of the world where water isn't properly treated, and also easily picked up by back-packers who fail to treat their water.
I don't believe that G. lamblia is either one. That is it cannot be identified via gram staining. A trichrome stain is needed to identify this bacteria. The trichome stain, originally a system of three colored dyes, illuminates the nuclei in the parasite and along with it's unique shape (that of a tear drop with two nuclei) identifies the parasite as giardia.
Domain:Eukaryota(unranked):ExcavataPhylum:MetamonadaOrder:DiplomonadidaFamily:HexamitidaeGenus:GiardiaSpecies:G. lambli
Domain:Eukaryota(unranked):ExcavataPhylum:MetamonadaOrder:DiplomonadidaFamily:HexamitidaeGenus:GiardiaSpecies:G. lambli
Yes it is. A protist that inhabits the limen of the small intestine where it subsists on the nutrients intended for the host.
Giardiasis is caused by a protozoa names Giardia lamblia. It is a water born pathogen that is excreted in the stool of people and many animals. The next host gets it when they drink the contaminated water. It is a common infection in people who drink from mountain streams.
The majority of infections with Giardia are asymptomatic. In the rare circumstances where disease takes place, younger animals tend to be affected, and the typical indication can be a slight repeating diarrhea composed of soft, light-colored stools. In serious cases, there may be a severe explosive diarrhea. Furthermore, it may be either intermittent, or chronic. The fecal material in many cases are abnormal, being pale, having a bad odor, as well as looking greasy.