Plasmodium circumflexum

Plasmodium circumflexum is a parasite of the genus Plasmodium subgenus Giovannolaia.
Like all Plasmodium species P. circumflexum has both vertebrate and insect hosts. The vertebrate hosts for this parasite are birds.

Taxonomy

The parasite was first described by Kikuth in 1931 in a juniper thrush. It may have been the same species previous described by Labbe in 1894 who thought it was a species of Haemoproteus.

Description

Schizonts: these are large and when mature may entirely encircle the erythrocyte nucleus.
Merozoites: each schizont gives rise to 13-30 merozoites.
Gametocytes: these are large and when mature may entirely encircle the erythrocyte nucleus.

Distribution

This parasite is found in Argentina, Brazil, Canada, Germany, Italy, Malaysia, Morocco, South Africa, Sri Lanka and the United States.

Vectors

Culiseta morsitans
Mansonia crassipes
Theobaldia annulata
Sporogeny but not transmission has been recorded in Mansonia perturbans.

Hosts

P. circumflexum has been recorded infecting the following hosts:

Shikra
Eurasian Sparrowhawk
Sharp-shinned hawk,
Red-winged blackbird,
Wood duck,
Canvasbacks,
Blue jay,
Cape May warbler,
Gray cat bird,
Slate colour junicao,
Song sparrow,
Common merganser,
Cowbird,
Finch,
Trumpeter swan,
Chestnut-tailed starling,
Brown thrasher,
White throated sparrow,
American robin,
Juniper thrush,
Wild guineafowl - the pathological features in acute cases include anaemia, jaundice and splenomegaly; in the subacute cases severe splenomegaly, right ventricular hypertrophy and multifocal interstitial myocarditis.
White throated sparrow