Haematozoa or Hematozoa is a general term that includes blood parasites, mainly protozoans. Well known examples include the malaria and trypanosoma parasites, but a large number of species are known to infect birds and are transmitted by arthropod vectors.
Infections of haematozoa can have adverse fitness effects on certain species. Species that have been isolated or not have been exposed to the infection have been found to be especially more vulnerable to pathogenic effects. The infection effects are able to persist in host avian species through long-distance migrations.
Blood parasites that have been studied were found to be transmitted by daematophagous dipteran vectors that have life stages in both aquatic and flighted.
Trypanosoma brucei ssp.
This group of protozoan parasites includes two agents which cause African sleeping sickness, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. A third, morphologically identical species, Trypanosoma brucei brucei, infects domestic and wild animals but does not cause disease in humans because it is lysed by apolipoproetin L1 in the high-density lipoprotein fraction of human serum.
The vector for these protozoans is the Tsetse Fly (Glossina spp.)