Leucocytozoonosis in the Israeli sparrow, Passer domesticus biblicus Hartert 1904.

Among the 91 house sparrows (Passer domesticus biblicus Hartert, 1904) examined and caught in the Jordan valley, Israel, 79% were found to be infected with Leucocytozoon fringillinarum Woodcock 1910. In the coastal plain of Israel (South of Tel Aviv), Leucocytozoon infection was found in only 3 out of 43 examined sparrows. In the birds examined, Leucocytozoon gametocytes were present, often in large numbers, in the circulating blood of the visceral organs, whereas they were only sporadic or even absent in the peripheral blood. Gametocytes were seen in the brain capillaries in only a few birds. Only one of the heavily infected sparrows was anemic. Leucocytozoon merozoites were present in the liver and kidneys in only a few infected birds. Merogonic infections did not induce any severe pathological changes, while the gametocyte congestion caused dilation of the blood vessels and sinuses. Tissue damage by the gametocyte parasitemia was most evident in the liver and kidneys. Leucocyte infiltration developed alongside the affected vessels; diffuse necrosis developed in the infiltrated areas. In the kidneys, many tubules were degenerated. Leucocytozoon gametocyte infection in sparrows is unique in that it appears to be confined, for most of its duration, to the visceral circulation, resulting in clinical consequences. Geographically, it is confined to habitats presumably supporting vectors.