Giardia

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Giardia
Different views of a Giardia cyst

Different views of a Giardia cyst

Systematics
Domain : Eukaryotes (eukaryota)
without rank: Excavata
without rank: Fornicata
without rank: Diplomonadida
without rank: Giardiinae
Genre : Giardia
Scientific name
Giardia
Artist , 1882

Giardia ( Giardia ) are a genus of microscopic small intestine - parasites . Similar to coccidia , they are traditionally counted among the protozoa , i. i.e., they are heterotrophic unicellular organisms . They occur worldwide in a large number of mammals , but also in amphibians , reptiles and birds. As zoonotic pathogens , they pose a threat to humans . Giardia ( lamblia ) are always transmitted via a faecal-oral route of infection. Infected animals or humans excrete Giardia as cysts (permanent form of Giardia) with the stool ( faeces ). Infections arise when Giardia are ingested from the stool (i.e. faeces) with the mouth (i.e. orally ). A widespread representative of the Giardia is Giardia intestinalis , also called Giardia lamblia or Giardia duodenalis , which attacks birds and mammals. Giardia agilis occurs in reptiles, Giardia muris in rodents and birds.

The intestinal parasites have a pear-shaped shape with two typical nuclei that look like a pair of eyes (in reality cell nuclei with genetic information ). Giardia use their flagella for locomotion . With the help of their abdominal adhesive disc, the diarrhea pathogens are able to attach themselves to the intestinal wall of the host, i.e. i.e., they do not penetrate the tissue. There they then multiply millions of times on the surface of the intestinal mucosa.

Two giardia can each be surrounded by a protective cover and excreted in the faeces. The shell protects them for days or weeks before they are ingested by the new host through contaminated water or food. The infectious parasites remain infectious in moist soils for up to seven weeks, in cool water (4 ° C) for up to three months, and under optimal conditions they can even remain viable for several months.

Many people and animals harbor Giardia in their intestines without feeling sick. Even so, they excrete the parasite with their stool. Other affected individuals experience nausea , abdominal pain, and diarrhea. In humans, Giardia infection usually takes place during a trip to tropical regions or adventure trips into the great outdoors. In fact, the hygienic conditions in these areas or "camps" are often unsatisfactory, so that contamination through water or food is easy.

Giardia pose a problem in drinking water treatment , they cannot be completely killed by chlorine or ultraviolet radiation . For this reason, ultrafiltration is often used for surface water treatment in order to filter it off.

species

The genus comprises 41 species (the host is given in brackets after the name):

See also

Web links

Commons : Giardia  - collection of images, videos and audio files

Individual evidence

  1. ↑ Dieter Barutzki et al .: The dog giardiosis - a widespread disease. In: Kleintier Konkret S1 (2008), pp. 17–23.
  2. ^ Giardia Kunstler , in: The Tree of Life Web Project, http://tolweb.org/ , Tree of Life Web Project, 2008, accessed on October 22, 2009