Plasmodium ashfordi
Encyclopedia
Plasmodium ashfordi is a species
of the genus
Plasmodium
subgenus Novyella
.
Like all species in this genus it has both vertebrate
and insect
hosts. The vertebrate host are bird
s.
The parasite infects erythrocytes.
The influence of trophozoites on the morphology of infected erythrocytes is not marked. The parasite nucleus is small, usually terminal in position or with chromatin concentrated along the outer periphery of trophozoites. One or two small (<1 µm in diameter) vacuoles are frequently present in the cytoplasm.
Ring forms are not characteristic.
The trophozoites are usually found in mature erythrocytes but may be seen in polychromatic erythrocytes during heavy infections. They are variable in shape, usually irregular in outline. Outgrowths extending beyond the main body of the trophozoites are absent. Fully grown trophozoites usually possess one or two minute brown pigment granules which are usually terminal in position and located close to each other.
The meronts are fan
-like and contain 7 - 8 merozoites (range: 4 - 10). They measure ~5.0 micrometre
s (range:3.3-6.2) in length, 2.2 micrometres in width (range: 1.7-3.1) and 9.4 square micrometres (range: 5.4-12.2) in area. The pigment granules occupy 0.8-1.3 square micrometres in area.
Fully grown gametocytes occupy positions lateral to the nuclei of infected erythrocytes.
They are elongated in form and irregular in outline from the earliest stages of their development. The influence of gametocytes on the morphology of infected erythrocytes usually is not pronounced, but nuclei of some infected erythrocytes may be slightly displaced laterally.
The parasite nucleus is diffuse and its boundaries are difficult to discern. The chromatin may be positioned anywhere in the gametocyte, which is a rare feature for macrogametocytes of avian hemosporidians. Pigment granules are roundish or oval in form, clumped together into a prominent group usually located terminally or occasionally subterminally. Because of this clumping, the number of pigment granules and their size are difficult to determine.
Macrogametocytes are found only in mature erythrocytes even during heavy parasitemia. They measure 9.7 micrometres (range: 7.1 - 12.3) long, 2.3 micrometres (range: 1.9 - 2.8) in width and 21.2 (range: 13.1 - 30.6) square micrometres in area. The cytoplasm is coarsely granular in appearance and usually lacks vacuoles.
The microgametocyte are 9.7 micrometres (range: 7.6 - 12.0) long, 2.2 micrometres (range: 1.6 - 2.6) in width and 19.8 (range: 13.5 - 25.1) square micrometres in area. Compared with the macrogametocytes, their nuclei are relatively compact - a rare feature for avian hemosporidians. The nuclei are located centrally or subcentrally.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Plasmodium
Plasmodium
Plasmodium is a genus of parasitic protists. Infection by these organisms is known as malaria. The genus Plasmodium was described in 1885 by Ettore Marchiafava and Angelo Celli. Currently over 200 species of this genus are recognized and new species continue to be described.Of the over 200 known...
subgenus Novyella
Novyella
Novyella is a subgenus of the genus Plasmodium - all of which are parastic protozoa. The subgenus was created in 1963 by created by Corradetti et al.. Species in this subgenus infect birds...
.
Like all species in this genus it has both vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
and insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
hosts. The vertebrate host are bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s.
Description
This species was first described in 2007 by Valkiunas et al.The parasite infects erythrocytes.
The influence of trophozoites on the morphology of infected erythrocytes is not marked. The parasite nucleus is small, usually terminal in position or with chromatin concentrated along the outer periphery of trophozoites. One or two small (<1 µm in diameter) vacuoles are frequently present in the cytoplasm.
Ring forms are not characteristic.
The trophozoites are usually found in mature erythrocytes but may be seen in polychromatic erythrocytes during heavy infections. They are variable in shape, usually irregular in outline. Outgrowths extending beyond the main body of the trophozoites are absent. Fully grown trophozoites usually possess one or two minute brown pigment granules which are usually terminal in position and located close to each other.
The meronts are fan
Fan (implement)
A hand-held fan is an implement used to induce an airflow for the purpose of cooling or refreshing oneself. Any broad, flat surface waved back-and-forth will create a small airflow and therefore can be considered a rudimentary fan...
-like and contain 7 - 8 merozoites (range: 4 - 10). They measure ~5.0 micrometre
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
s (range:3.3-6.2) in length, 2.2 micrometres in width (range: 1.7-3.1) and 9.4 square micrometres (range: 5.4-12.2) in area. The pigment granules occupy 0.8-1.3 square micrometres in area.
Fully grown gametocytes occupy positions lateral to the nuclei of infected erythrocytes.
They are elongated in form and irregular in outline from the earliest stages of their development. The influence of gametocytes on the morphology of infected erythrocytes usually is not pronounced, but nuclei of some infected erythrocytes may be slightly displaced laterally.
The parasite nucleus is diffuse and its boundaries are difficult to discern. The chromatin may be positioned anywhere in the gametocyte, which is a rare feature for macrogametocytes of avian hemosporidians. Pigment granules are roundish or oval in form, clumped together into a prominent group usually located terminally or occasionally subterminally. Because of this clumping, the number of pigment granules and their size are difficult to determine.
Macrogametocytes are found only in mature erythrocytes even during heavy parasitemia. They measure 9.7 micrometres (range: 7.1 - 12.3) long, 2.3 micrometres (range: 1.9 - 2.8) in width and 21.2 (range: 13.1 - 30.6) square micrometres in area. The cytoplasm is coarsely granular in appearance and usually lacks vacuoles.
The microgametocyte are 9.7 micrometres (range: 7.6 - 12.0) long, 2.2 micrometres (range: 1.6 - 2.6) in width and 19.8 (range: 13.5 - 25.1) square micrometres in area. Compared with the macrogametocytes, their nuclei are relatively compact - a rare feature for avian hemosporidians. The nuclei are located centrally or subcentrally.