Trypanosoma brucei spp

Harris, E., et al. (1996). Detection of Trypanosoma brucei spp. in human blood by a nonradioactive branched DNA-based technique. J. Clin. Microbiol 34,2401-2407. 

Protozoan parasites are responsible for some of the most devastating and prevalent diseases of humans and domestic animals. Protozoan parasites threaten the lives of nearly one-third of the worldwide human population, and are responsible for the loss of more than 50 million disability-adjusted life years (DALYs) and more than 2 million deaths a year. The parasite species responsible for malaria Plasmodium spp) are at the forefront in terms of their ability to inflict devastating effects and mortality on the human population, but the parasites responsible for the various forms of leishmaniasis (Leishmania spp), African sleeping sickness Trypanosoma brucei) and Chagas disease Trypanosoma cruzi) are also important contributors to global morbidity and mortality figures. Many other parasitic species also contribute significantly to the world s disease burden. 

I have talked mostly about eukaryotic cells, so I should mention here the regulation of RNA polymerase of E. coli by an ADPRT of phage T4. This example, and the presence of ADPRT enzymes in protozoa such di Physarum polycephaluniy Tetrahymena pyriformis, Dictyosteleum discoideum, Trypanosoma cruzi, Trypanosoma brucei and probably va Plasmodium spp. show that ADPRT enzymes evolved at a fairly early stage in evolution. 

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