Trypanosomatids: Odd Organisms, Devastating Diseases

Abstract

Trypanosomatids cause many diseases in and on animals (including humans) and plants. Altogether, about 37 million people are infected with Trypanosoma brucei (African sleeping sickness), Trypanosoma cruzi (Chagas disease) and Leishmania species (distinct forms of leishmaniasis worldwide). The class Kinetoplastea is divided into the subclasses Prokinetoplastina (order Prokinetoplastida) and Metakinetoplastina (orders Eubodonida, Parabodonida, Neobodonida and Trypanosomatida) [1,2]. The Prokinetoplastida, Eubodonida, Parabodonida and Neobodonida can be free-living, commensalic or parasitic; however, all members of theTrypanosomatida are parasitic. Although they seem like typical protists under the microscope the kinetoplastids have some unique features. In this review we will give an overview of the family Trypanosomatidae, with particular emphasis on some of its "peculiarities" (a single ramified mitochondrion; unusual mitochondrial DNA, the kinetoplast; a complex form of mitochondrial RNA editing; transcription of all protein-encoding genes polycistronically; trans-splicing of all mRNA transcripts; the glycolytic pathway within glycosomes; T. brucei variable surface glycoproteins and T. cruzi ability to escape from the phagocytic vacuoles), as well as the major diseases caused by members of this family. However, the present review does not cover all trypanosomatids; for example, the insect trypanosomatids are underrepresented here. On the other hand, reviews on this particular group of parasites have been written by experts in the field [3-12].

The Immune Response of Hemocytes of the Insect Oncopeltus fasciatus against the Flagellate Phytomonas serpens

“…The transmission to plants occurs through the saliva of phytophagous hemipteran [2]. When these insects become infected while feeding on an infected plant, the parasites colonize the midgut and once a midgut infection is established, they cross the midgut epithelium, thereby gaining access to the hemocoel when the systemic infection occurs [1]–[3]. In the final step of insect colonization, parasites from the hemolymph bind to and invade the insect salivary glands [4], [5].…”

Two flagellar BAR domain proteins in Trypanosoma brucei with stage-specific regulation

“…Some species of this order are the causative agents of various infectious diseases distributed in many parts of the world, with a devastating impact on human health and the economies of impoverished countries. For example, Leishmania donovani causes visceral leishmaniasis (Kala-Azar) in South and Central America, South Europe, Africa and West Asia; Trypanosoma cruzi causes Chagas disease in South America; Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense are responsible for sleeping sickness in humans (human African trypanosomiasis, HAT), and Trypanosoma brucei brucei causes nagana in livestock in sub-Saharan Africa2. Both Leishmania and the two Trypanosoma species are transmitted to mammals by bloodsucking insects.…”

Mono- and Dithiol Glutaredoxins in the Trypanothione-Based Redox Metabolism of Pathogenic Trypanosomes

“…The parasites present a complex life cycle with stages in specific arthropods and the mammalian host(s). Trypanosomatids display a number of morphological and metabolic peculiarities (50). For instance, the parasite thiol redox homeostasis is maintained by the unique trypanothione/trypanothione reductase couple, which substitutes for the glutathione/ glutathione reductase and the thioredoxin/thioredoxin reductase systems of the host (24,39,44,45).…”