Kinetoplastea

Authority:

Kinetoplastea
Kingdom:
Phylum:	Euglenozoa
Class:	Kinetoplastea
Order:
Family:	'

Kinetoplastea is a class of flagellate protists belonging to the phylum Euglenozoa. These organisms are characterized by the presence of a unique organelle called the kinetoplast, which is a large mass of DNA located within the single, large mitochondrion of the cell. Kinetoplastids are primarily known for including several medically and economically important parasites, such as those causing African sleeping sickness and Chagas disease.

Morphology

Kinetoplastids are distinguished by their single, large mitochondrion that contains the kinetoplast. The kinetoplast is a network of circular DNA molecules, known as kDNA, which are organized into a dense structure. This organelle is typically located near the base of the flagellum, which is used for locomotion.

The cell body of kinetoplastids is elongated and often spindle-shaped, with a single flagellum that emerges from a pocket-like structure. The flagellum may be free or attached to the cell body, forming an undulating membrane.

Life Cycle

Kinetoplastids exhibit complex life cycles, often involving multiple hosts. For example, the genus Trypanosoma includes species that are transmitted by insect vectors. Trypanosoma brucei, the causative agent of African sleeping sickness, is transmitted by the tsetse fly, while Trypanosoma cruzi, responsible for Chagas disease, is transmitted by triatomine bugs.

The life cycle typically involves alternating between a mammalian host and an insect vector, with different morphological forms adapted to each environment. In the mammalian host, the parasites multiply in the bloodstream or tissues, while in the insect vector, they undergo further development and multiplication.

Pathogenicity

Several kinetoplastids are significant human pathogens. Trypanosoma brucei causes African sleeping sickness, characterized by fever, headaches, joint pains, and neurological symptoms. Trypanosoma cruzi causes Chagas disease, which can lead to severe cardiac and digestive system complications.

Another important genus is Leishmania, which causes leishmaniasis, a disease transmitted by sandflies. Leishmaniasis can manifest in cutaneous, mucocutaneous, or visceral forms, depending on the species involved.

Research and Treatment

Research on kinetoplastids focuses on understanding their unique biology, particularly the kinetoplast DNA, and developing effective treatments for the diseases they cause. Current treatments for diseases like African sleeping sickness and Chagas disease are limited and can have significant side effects, highlighting the need for new therapeutic approaches.

Also see

• Trypanosomatida
• Leishmania
• Euglenozoa
• Flagellate
• Parasitology