Hosts: Domestic pigeon, mourning dove (Zenaidura macroura), turtle dove (Streptopelia turtur). This species is primarily a parasite of wild doves which may also infect pigeons.
Location: Gametocytes in erythrocytes. Schizogony in endothelial cells of blood vessels.
Geographic Distribution: North America, Europe (Italy).
Prevalence: H. sacharovi is common in mourning doves. Levine and Kantor (1959) tabulated 12 reports from this host from coast to coast in the United States. Among those studies in which relatively large numbers of birds were examined, Herman (1938) found it in 7% of 86 mourning doves on Cape Cod, Massachusetts, Huff (1939) found it in 56% of 188 mourning doves, mostly from Illinois, Coatney and West (1940) found it in 67% of 18 mourning doves in Nebraska, Couch (1952) found it in 27% of 213 mourning doves in Texas, Wood and Herman (1943) found it in 41% of 27 western mourning doves in Arizona and California, and Hanson et al. (1957) found it in 58% of 392 immature and 43% of 72 adult mourning doves in Illinois. In this last study, its incidence was 31% in very young doves and 52% to 69% in older birds. Its incidence varied markedly in different parts of the state and in different years.
H. sacharovi was found in 22% of 50 domestic pigeons in Nebraska by Coatney and West (1940) and in 15% of 20 domestic pigeons in Iowa by Becker, Hollander and Pattillo (1956).
Morphology: The macrogametes and microgametocytes are found in the erythrocytes. They differ from those of most species of Haemoproteus in that when mature they completely fill the host cell, enlarging and distorting it, and often pushing the host cell nucleus to the edge of the cell. In addition, they contain very little pigment. When stained with a Romanowsky stain, the microgametocytes have pale blue to almost colorless cytoplasm and a light pink, diffuse nucleus, while the macrogametes have dark blue cytoplasm and a dark pink to red, compact nucleus.
The young gametocytes are ring-forms, and all stages between these and mature gametocytes can be found in the blood.
Life Cycle: Huff (1932) transmitted H. sacharovi from the mourning dove to the pigeon by means of the hippoboscid fly, Pseudolynchia canariensis. However, the natural vectors of this protozoon are still unknown. In view of its high incidence in mourning doves and the extreme rarity of hippoboscid flies on these birds, the natural vector must be some other ectoparasite, possibly Culicoides.
Pathogenesis: H. sacharovi is only slightly if at all pathogenic in the mourning dove. Becker, Hollander and Pattillo (1956) considered that it caused the enlarged, purplish livers which they encountered in dressing domestic pigeon squabs from an infected flock; there was apparently no other evidence of disease.