trypanosome

Trypanosomes are flagellated protozoan parasites of the genus Trypanosoma, within the family Trypanosomatidae. They are kinetoplastids, characterized by a single, large mitochondrion containing a kinetoplast. The genus includes many species that infect a wide range of vertebrates and invertebrate vectors. The parasites exhibit complex life cycles that alternate between an insect vector and a vertebrate host, with distinct morphological forms such as bloodstream trypomastigotes in vertebrates and epimastigotes in the insect midgut and salivary glands. Antigenic variation, particularly in Trypanosoma brucei, allows evasion of host immune responses through changing surface glycoproteins.

The most prominent human pathogens are Trypanosoma brucei and Trypanosoma cruzi. T. brucei causes African trypanosomiasis (sleeping sickness), transmitted by tsetse flies (Glossina). T. brucei gambiense and T. brucei rhodesiense differ in geographic distribution and disease course, with gambiense typically causing a chronic illness and rhodesiense a more acute form. T. cruzi causes American trypanosomiasis (Chagas disease), transmitted mainly by triatomine bugs, and can involve chronic cardiomyopathy or gastrointestinal complications. Other trypanosomes affect livestock and wildlife, causing diseases such as nagana.

Diagnosis relies on detecting parasites in blood, lymph, bone marrow, or CSF, supplemented by serology or molecular methods. Treatments vary by species and disease stage and may include drugs such as pentamidine, suramin, eflornithine, nifurtimox–eflornithine combination therapy, melarsoprol for late-stage African trypanosomiasis, and benznidazole or nifurtimox for Chagas disease.

Prevention focuses on vector control, protected housing, screening of blood products, and public health measures to reduce transmission in endemic areas.