''Plasmodium yoelii'' is a parasite of the genus ''

Plasmodium ''Plasmodium'' is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of ''Plasmodium'' species involve development in a blood-feeding insect host which then injects parasites into a vert ...

'' subgenus ''

Vinckeia ''Vinckeia'' is a subgenus of the genus ''Plasmodium'' — all of which are parasitic alveolates. The subgenus ''Vinckeia'' was created by Cyril Garnham in 1964 to accommodate the mammalian parasites other than those infecting the primates. Di ...

''. As in all ''Plasmodium'' species, ''P. yoelii'' has both

vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...

and

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

hosts. The vertebrate hosts for this parasite are

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

Taxonomy

This species was described in 1968 by Landau, Michel and Adam. Three subspecies are recognised: ''P. y. killicki'', ''P. y. nigeriensis'' and ''P. y. yoelli''.

Strains

*''P. yoelii''

Distribution

This species occurs in Africa.

Vectors

The natural vectors of this species are not currently known. One possible is the female ''

Anopheles ''Anopheles'' () is a genus of mosquito first described and named by J. W. Meigen in 1818. About 460 species are recognised; while over 100 can transmit human malaria, only 30–40 commonly transmit parasites of the genus ''Plasmodium'', which c ...

'' mosquito which serves as a vector for ''

Plasmodium vivax ''Plasmodium vivax'' is a protozoal parasite and a human pathogen. This parasite is the most frequent and widely distributed cause of recurring malaria. Although it is less virulent than ''Plasmodium falciparum'', the deadliest of the five huma ...

''.

Hosts

This species infects ''

Thamnomys rutilans The shining thicket rat (''Grammomys poensis'') is a species of rodent in the family Muridae. Distribution and habitat It is found in Angola, Burundi, Cameroon, Central African Republic, Republic of the Congo, Democratic Republic of the Congo ...

.''

Pathogenesis

''P. yoelii'' impairs immune responses including impairing responses to other pathogens. Fewer granulocytes move out from the bone marrow and in a separate action induces the rodent's own

heme oxygenase 1 ''HMOX1'' (heme oxygenase 1 gene) is a human gene that encodes for the enzyme heme oxygenase 1 (). Heme oxygenase (abbreviated HMOX or HO) mediates the first step of heme catabolism, it cleaves heme to form biliverdin. The ''HMOX'' gene is locate ...

(HO-1). Although HO-1 induction is a tolerance response by the host to malaria preventing damage caused by the host's own immune response the reduced

reactive oxygen species In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen. The reduction of molecular oxygen () p ...

production takes away a weapon vital to fighting some unrelated microbes. Cunnington et al. 2012 find mice tolerating ''P. yoelii'' 17XNL do ''not'' clear

coinfection Coinfection is the simultaneous infection of a host by multiple pathogen species. In virology, coinfection includes simultaneous infection of a single cell by two or more virus particles. An example is the coinfection of liver cells with hepatiti ...

s with other pathogens as easily as they normally would.

Notes

It is used in the laboratory to infect

mice A mouse ( : mice) is a small rodent. Characteristically, mice are known to have a pointed snout, small rounded ears, a body-length scaly tail, and a high breeding rate. The best known mouse species is the common house mouse (''Mus musculus' ...

, as a model of human

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

, particularly with respect to the

immune response An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could ...

. It is advantageous to have a whole-

animal model An animal model (short for animal disease model) is a living, non-human, often genetic-engineered animal used during the research and investigation of human disease, for the purpose of better understanding the disease process without the risk of ha ...

of malaria because often it is difficult to know which factors to study ''in vitro'', particularly in a complex system like the

immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...

. Moreover, for many experiments it is not ethical or practical to use humans. One of the special things about this particular model is that it has two strains with vastly different pathogenicity. These are generally referred to as the "lethal" and "non-lethal" strains of the species. Comparison of these two strains can be used to deduce which factors may contribute to more serious malaria infections in humans.

References

External links

;Information about the genome and genes of ''P. yoelii'':
www.genedb.org/Homepage/PyoeliiYM
{{Taxonbar, from=Q12065970 yoelii Parasites of rodents