Piroplasmida is an
order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
of
parasite
Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted structurally to this way of lif ...
s in the
phylum
In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclatu ...
Apicomplexa
The Apicomplexa (also called Apicomplexia) are a large phylum of parasitic alveolates. Most of them possess a unique form of organelle that comprises a type of non-photosynthetic plastid called an apicoplast, and an apical complex structure. The ...
. They divide by
binary fission
Binary may refer to:
Science and technology Mathematics
* Binary number, a representation of numbers using only two digits (0 and 1)
* Binary function, a function that takes two arguments
* Binary operation, a mathematical operation that ta ...
and as
sporozoan parasites they possess
sexual and
asexual phases (sexual reproduction occurs in the tick gut). They include the
tick
Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
parasites ''
Babesia'' and ''
Theileria
''Theileria'' is a genus of parasites that belongs to the phylum Apicomplexa, and is closely related to '' Plasmodium''. Two ''Theileria'' species, ''T. annulata'' and ''T. parva'', are important cattle parasites. ''T. annulata'' causes tropical ...
''.
Description
They are minute rounded or
pyriform parasites found within erythrocytes, or other circulating or endothelial cells of vertebrates, where they reproduce by
merogony. The
trophozoite A trophozoite (G. ''trope'', nourishment + ''zoon'', animal) is the activated, feeding stage in the life cycle of certain protozoa such as malaria-causing ''Plasmodium falciparum'' and those of the ''Giardia'' group. (The complement of the trophozoi ...
stage is separated from erythrocyte by a single membrane. This distinguishes them from other blood parasites that usually have at least two membranes.
An
apical complex with a polar ring and rhopteries occurs, but without a
conoid and usually without associated pellicular microtubules. They lack
flagella
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates.
A microorganism may have f ...
and do not form either
oocysts or spores.
The known vectors are
tick
Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...
s or
leeches in which they undergo
sporogony; sexual reproduction probably occurs in the vector.
See also
*
Babesiosis
Babesiosis or piroplasmosis is a malaria-like parasitic disease caused by infection with a eukaryotic parasite in the order Piroplasmida, typically a '' Babesia'' or ''Theileria'', in the phylum Apicomplexa. Human babesiosis transmission vi ...
*
Equine piroplasmosis
References
Apicomplexa orders
{{Apicomplexa-stub