Pathology associated with endogenous development of haematozoa in birds from southeast Queensland

Abstract

A study was undertaken on the pathology and associated schizont morphology of apicomplexan species of avian haematozoa. Some 32 birds from the families Artamidae, Meliphagidae, Oriolidae, Podargidae, Columbidae, Alcedinidae and Psittacidae were identified as having schizonts in various tissues. Based on blood stages observed, the probable relationship to tissue stages was considered. The majority of schizonts were referable to the genera Leucocytozoon and Haemoproteus. The comparative morphology of tissue stages previously described in the literature is discussed and the involvement of protozoa other than haematozoa considered. The naturally occurring infections in wild birds described in this study represent previously unreported data on the life-cycle stages involved. Some schizonts measured up to 640 mm. While pathological changes in some hosts were noticeable, in others no significant findings were observed. The role of endogenous stages in avian morbidity is discussed briefly.

Hepatic Hemorrhage, Hemocoelom, and Sudden Death due to Haemoproteus Infection in Passerine Birds: Eleven Cases

“…18,20 Elongate Haemoproteus schizonts were described in the lung and pulmonary vasculature of a domestic pigeon, causing tissue displacement and blockage of pulmonary vessels, and an ovoid Haemoproteus schizont was found in the skeletal muscle of a sacred kingfisher, with no significant inflammation and circulating gametocytes in both cases. 20 Compartmentalized protozoal schizonts were reported to occur in the lungs, liver, and heart of a sparrow from Israel, similar to those previously described in Baghdad sparrows, 18 and were attributed to Haemoproteus, based upon the morphology of intraerythrocytic gametocytes. Hepatocytes that surrounded the schizonts exhibited fatty degeneration, whereas schizonts in the lungs were surrounded by mild inflammation and hemorrhage.…”

“…Concurrent mixed infections and taxonomic changes are additional obstacles that may prohibit correct identification of hemoparasites. 10,20 The current study's gross and histologic findings may represent a disease entity that was previously described but incompletely understood. There are many reports of liver hemorrhage and necrosis in passerine and nonpasserine birds of the United States attributed to protozoal schizonts, 11,17 but the protozoal identity was either undetermined or thought to be an aberrant form of Leukocytozoon.…”

“…20 Future studies should include confirmation and identification of vectors, as well as demonstration of the same Haemoproteus spp. in surrounding native bird populations.…”

A new species of Leucocytozoon Berestneff, 1904 (Apicomplexa: Leucocytozoidae) from the avian family Artamidae

“…Larger schizonts measuring 25-360 × 30-160 µm and assumed to be second generation megaloschizonts were observd in kidney (Figure 8), spleen and lung of all 3 hosts, but only in cardiac muscle of G. tibicen and S. graculina. Pathology associated with tissue schizonts is described elsewhere (see Peirce et al, 2004). Both first and second generation schizonts are characterised by cytomere formation.…”

Evaluation of the Blood Film

“…Many species of Plasmodium are capable of infecting a wide range of hosts. 26 Parasites of the genus Plasmodium can be pathogenic and are responsible for malaria. Certain species of birds, such as canaries, penguins, ducks, pigeons, raptors, and domestic poultry, are highly susceptible to avian malaria, whereas other species of birds seem to be asymptomatic carriers of the parasite and do not develop the clinical disease.…”