Pathogenicity and epizootiology of avian haematozoa: Plasmodium, Leucocytozoon, and Haemoproteus

Abstract

Abstract A diverse group of parasitic helminths and protozoans use the avian bloodstream as a habitat for growth and reproduction. These parasites include the filarial nematodes which live in the tissues or peritoneal cavity of their hosts and release larval microfilariae into the circulation, flagellated trypanosomes which divide and circulate in the bloodstream, and intracellular sporozoan parasites (phylum: Apicomplexa) which complete part of their complex life cycles within circulating blood cells. Within this last group, the haemosporidian parasites of birds, i.e. species of Plasmodium, Leucocytozoon, and Haemoproteus, have been studied intensely by parasitologists in all of the major zoogeographic regions of the world. An extensive body of literature has accumulated on the biology of these organisms during the past century which makes them exceptional candidates for studies of the evolution of bird–parasite interactions and outstanding reference systems for studies of other vertebrate–parasite interactions.