Flagellates

The group of flagellates was first described in 1866 by botanist Karl Moritz Diesing. However, the final recognition took place only at the end of the 20th century as a genus of protozoa.

Flagellates are unicellular, eukaryotic organisms that develop one or more flagella that enable them to move around. With the help of the flagella they are also able to anchor themselves to structures. Flagellates, like all protozoa, are classified in the animal kingdom. Some flagellates can cause diseases in humans. These include:

Trypanosomes

• Trypanosoma brucei rhodesiense (Africa)
• Trypanosoma brucei gambiense (Africa)
• Trypanosoma cruzi (Central and South America)

Leishmania

• Leishmania donovani (Africa, Asia, Europe)
• Leishmania infantum (Mediterranean area)
• Leishmania chagasi (Central and South America)
• Leishmania amazonensis (South America)
• Leishmania tropica (Africa, Asia, Europe)
• Leishmania major (Africa, Asia, Europe)
• Leishmania aethopica (Africa, Asia, Europe)
• Leishmania mexicana (Central and South America)
• Leishmania peruviana (South America)
• Leishmania brasiliensis (Central and South America)
• Leishmania mexicana (mucocutaneous form)

Trichomonas

• Trichomonads are transmitted through sexual intercourse and cause inflammatory urogenital diseases.

Giardia

• Giardia duodenalis (Giardia lamblia/intestinalis)

Trypanosoma: These flagellates belong to the Trypanosomatidae family, which also includes Leishmania. The most important representatives are Trypanosoma brucei gambiense, Trypanosoma brucei rhodesiense as the causative agent of African trypanosomiasis (sleeping sickness). Trypanosoma cruzi is the causative agent of American trypanosomiasis, Chagas disease. The vector is the blood-sucking tsetse fly (Glossina)

Leishmania: Leishmania belong to the Trypanosomatidae family. They are the causative agent of leishmaniasis. There are a total of 15 different human pathogenic Leishmania. Leishmania are mainly transmitted by sand flies of the genus Phlebotomus. The main areas of distribution of the pathogens are India, Africa, China, Iraq and the south-western Arabian Peninsula. Possible pathogens of leishmaniasis are Leishmania brasiliensis, Leishmania infantum and Leishmania tropica.

Trichomonas: Trichomonads are transmitted through sexual intercourse and are the cause of inflammatory urogenital diseases.

Giardia: Occurrence: Human giardiasis is a true cosmopolitan pathogen, with the highest prevalence in developing countries. Infection occurs by oral ingestion of the cysts in water or food. The small intestine parasite causes enteritis in humans.

1. Alberts, B. et al: Molecular Biology of the Cell. Wiley-VCH, Weinheim 2003
2. Darai, G., Handermann, M. et al: Encyclopedia of infectious diseases of humans. Springer, Berlin 2011
3. Halliez MC et al.(2013) Extra-intestinal and long term consequences of Giardia duodenalis infections. World J Gastroenterol 19:8974-8985