The aim of this bachelor thesis is to summarize the knowledge about the development of avian trypanosomes in the vector, and about their prevalence in avian hosts. Trypanosomes are dixenous parasitic protists. They live in the bloodstream of vertebrates and in invertebrate vectors. Replication of avian trypanosomes occurs mainly in the vector. Promastigote, epimastigote and metacyclic trypomastigote stages were observed in the vector already in the 1950s. In avian blood, bloodstream trypomastigotes occur. The vectors of avian trypanosomes are members of families Ceratopogonidae, Culicidae, Simuliidae, Hippoboscidae and Dermanyssidae. Although replication of trypanosomes has been seen in the vector, observations of division in birds are scarse. Results concerning prevalence of trypanosomes in birds considerably differ between different studies. This is mostly due to differences in methods used to detect trypanosomes from avian blood. Whereas detection from blood smears was used in the past, nowadays, more sensitive methods have been introduced, such as PCR or cultivation of trypanosome
