Plasmodium ovale: Difference between revisions

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[[File:Relative incidence of Plasmodium (malaria) species by country of origin for imported cases to non-endemic countries.png|thumb]] [[File:Microphotograph of Plasmodium ovale microgametocyte in Giemsa-stained thin blood film, with Schüffner's dots and hemozoin pigment.png|thumb]] [[File:Microphotographs of Plasmodium ovale in Giemsa-stained thin blood films.jpg|thumb]] [[File:IEcycle.PNG|thumb]] Plasmodium ovale
==Plasmodium ovale==


'''Plasmodium ovale''' is a protozoan parasite and one of the species of Plasmodium that cause malaria in humans. It is one of the less common causes of malaria, with the others being [[Plasmodium falciparum]], [[Plasmodium vivax]], [[Plasmodium malariae]], and [[Plasmodium knowlesi]].
[[File:Plasmodium_ovale_01.png|thumb|right|Plasmodium ovale in a blood smear]]


==Taxonomy and Classification==
'''Plasmodium ovale''' is a protozoan parasite and one of the species of [[Plasmodium]] that cause [[malaria]] in humans. It is one of the five species of Plasmodium that commonly infect humans, the others being [[Plasmodium falciparum]], [[Plasmodium vivax]], [[Plasmodium malariae]], and [[Plasmodium knowlesi]].
Plasmodium ovale belongs to the genus [[Plasmodium]], which is part of the phylum [[Apicomplexa]]. This genus is known for its role in causing malaria, a disease transmitted by the bite of infected [[Anopheles]] mosquitoes. P. ovale is further divided into two subspecies: '''Plasmodium ovale curtisi''' and '''Plasmodium ovale wallikeri'''.
 
==Morphology==
 
[[File:Microphotograph_of_Plasmodium_ovale_microgametocyte_in_Giemsa-stained_thin_blood_film,_with_Schüffner's_dots_and_hemozoin_pigment.png|thumb|left|Microphotograph of Plasmodium ovale microgametocyte in Giemsa-stained thin blood film, showing Schüffner's dots and hemozoin pigment]]
 
Plasmodium ovale is characterized by its oval-shaped infected red blood cells, which are slightly larger than uninfected cells and have a fimbriated edge. The presence of Schüffner's dots and hemozoin pigment is also a distinguishing feature. The parasite undergoes a complex life cycle involving both asexual and sexual stages.


==Life Cycle==
==Life Cycle==
The life cycle of Plasmodium ovale is similar to that of other Plasmodium species and involves two hosts: the human host and the mosquito vector.


===In the Human Host===
The life cycle of Plasmodium ovale involves two hosts: the human host and the [[Anopheles]] mosquito. In humans, the parasite undergoes asexual reproduction in the liver and red blood cells. The sexual stage occurs in the mosquito, where the parasite undergoes fertilization and development into sporozoites, which are then transmitted back to humans through a mosquito bite.
1. '''Sporozoite Stage''': The infection begins when an infected Anopheles mosquito bites a human, injecting sporozoites into the bloodstream.
2. '''Liver Stage''': The sporozoites travel to the liver, where they invade hepatocytes and develop into schizonts. This stage can last for about 9-14 days.
3. '''Blood Stage''': Schizonts rupture, releasing merozoites into the bloodstream. These merozoites invade red blood cells, where they undergo asexual reproduction, leading to cycles of fever and chills characteristic of malaria.
4. '''Hypnozoite Stage''': P. ovale can form dormant liver stages known as hypnozoites, which can reactivate and cause relapses weeks or months after the initial infection.


===In the Mosquito Vector===
==Epidemiology==
1. '''Gametocyte Stage''': Some merozoites develop into sexual forms called gametocytes, which are taken up by a mosquito during a blood meal.
 
2. '''Fertilization and Oocyst Formation''': In the mosquito's gut, gametocytes fertilize to form zygotes, which develop into ookinetes and then oocysts.
[[File:Relative_incidence_of_Plasmodium_(malaria)_species_by_country_of_origin_for_imported_cases_to_non-endemic_countries.png|thumb|left|Relative incidence of Plasmodium species by country of origin for imported cases to non-endemic countries]]
3. '''Sporozoite Formation''': Oocysts release sporozoites, which migrate to the mosquito's salivary glands, ready to infect a new human host.
 
Plasmodium ovale is primarily found in sub-Saharan Africa, but it can also be found in parts of Asia and the Western Pacific. It is less common than Plasmodium falciparum and Plasmodium vivax. The incidence of Plasmodium ovale is often underestimated due to its similarity to Plasmodium vivax and the lack of specific diagnostic tools.


==Clinical Features==
==Clinical Features==
Plasmodium ovale malaria is generally less severe than that caused by P. falciparum. Symptoms include:
- Fever
- Chills
- Headache
- Muscle aches
- Fatigue
The fever pattern in P. ovale malaria is typically tertian, meaning it recurs every 48 hours.


==Diagnosis==
Infection with Plasmodium ovale causes a form of malaria that is generally less severe than that caused by Plasmodium falciparum. Symptoms include fever, chills, headache, and muscle aches. The disease can cause relapses due to dormant liver stages known as hypnozoites.
Diagnosis of P. ovale infection is primarily through microscopic examination of blood smears, where the parasite can be identified by its characteristic oval-shaped infected red blood cells. Molecular methods such as PCR can also be used for more accurate identification.


==Treatment==
==Diagnosis and Treatment==
The treatment for P. ovale malaria includes:
* '''Chloroquine''': For the blood stage of the parasite.
* '''Primaquine''': To eliminate hypnozoites in the liver and prevent relapses.


==Epidemiology==
[[File:Microphotographs_of_Plasmodium_ovale_in_Giemsa-stained_thin_blood_films.jpg|thumb|right|Microphotographs of Plasmodium ovale in Giemsa-stained thin blood films]]
Plasmodium ovale is primarily found in sub-Saharan Africa, but cases have also been reported in Southeast Asia and the Western Pacific. It is less prevalent than P. falciparum and P. vivax.


==Prevention==
Diagnosis of Plasmodium ovale infection is typically made by microscopic examination of blood smears stained with Giemsa. Molecular methods such as PCR can also be used for more accurate diagnosis. Treatment involves the use of antimalarial drugs such as chloroquine and primaquine, the latter being used to eliminate hypnozoites and prevent relapses.
Preventive measures include:
- Use of insecticide-treated bed nets.
- Indoor residual spraying.
- Prophylactic antimalarial drugs for travelers to endemic areas.


==Also see==
==Related Pages==
* [[Malaria]]
* [[Malaria]]
* [[Plasmodium falciparum]]
* [[Plasmodium falciparum]]
* [[Plasmodium vivax]]
* [[Plasmodium vivax]]
* [[Anopheles]]
* [[Anopheles]]
* [[Antimalarial drugs]]
{{Malaria}}
{{Protozoa}}


[[Category:Plasmodium]]
[[Category:Plasmodium]]
[[Category:Parasitic diseases]]
[[Category:Parasites]]
[[Category:Malaria]]
[[Category:Malaria]]

Latest revision as of 20:50, 22 February 2025

Plasmodium ovale[edit]

Plasmodium ovale in a blood smear

Plasmodium ovale is a protozoan parasite and one of the species of Plasmodium that cause malaria in humans. It is one of the five species of Plasmodium that commonly infect humans, the others being Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, and Plasmodium knowlesi.

Morphology[edit]

Microphotograph of Plasmodium ovale microgametocyte in Giemsa-stained thin blood film, showing Schüffner's dots and hemozoin pigment

Plasmodium ovale is characterized by its oval-shaped infected red blood cells, which are slightly larger than uninfected cells and have a fimbriated edge. The presence of Schüffner's dots and hemozoin pigment is also a distinguishing feature. The parasite undergoes a complex life cycle involving both asexual and sexual stages.

Life Cycle[edit]

The life cycle of Plasmodium ovale involves two hosts: the human host and the Anopheles mosquito. In humans, the parasite undergoes asexual reproduction in the liver and red blood cells. The sexual stage occurs in the mosquito, where the parasite undergoes fertilization and development into sporozoites, which are then transmitted back to humans through a mosquito bite.

Epidemiology[edit]

Relative incidence of Plasmodium species by country of origin for imported cases to non-endemic countries

Plasmodium ovale is primarily found in sub-Saharan Africa, but it can also be found in parts of Asia and the Western Pacific. It is less common than Plasmodium falciparum and Plasmodium vivax. The incidence of Plasmodium ovale is often underestimated due to its similarity to Plasmodium vivax and the lack of specific diagnostic tools.

Clinical Features[edit]

Infection with Plasmodium ovale causes a form of malaria that is generally less severe than that caused by Plasmodium falciparum. Symptoms include fever, chills, headache, and muscle aches. The disease can cause relapses due to dormant liver stages known as hypnozoites.

Diagnosis and Treatment[edit]

Microphotographs of Plasmodium ovale in Giemsa-stained thin blood films

Diagnosis of Plasmodium ovale infection is typically made by microscopic examination of blood smears stained with Giemsa. Molecular methods such as PCR can also be used for more accurate diagnosis. Treatment involves the use of antimalarial drugs such as chloroquine and primaquine, the latter being used to eliminate hypnozoites and prevent relapses.

Related Pages[edit]