Life cycle Plasmodium Falciparum Flashcards
What is the classification of Plasmodium Falciparum?
Protozoa in the category Sporozoans
What are the 5 human plasmodium spp.?
P. Falciparum P. Vivax P. Malariae P. Knowlesi P. Ovale
How is Plasmodium Falciparum transmitted?
Mosquito bloodmeal
What are the 3 cycles of the Plasmodium lifecycle?
Exo-erythrocytic cycle
Erythrocytic Cycle
Sporogonic Cycle
What happens in the Exo-erythrocytic cycle of Plasmodium?
This is the initial replication cycle in the liver of the human host. Takes 6 days and happens only once
What are the life cycle steps of the Exo-erythrocytic cycle of Plasmodium?
- During a blood meal, a malaria-infected female Anopheles mosquito inoculates sporozoites into the human host
- Sporozoites infect liver cells
- Sporozoites in the liver cells mature into schizonts
- Liver cells with schizonts rupture and release merozoites
What happens in the erythrocytic cycle of Plasmodium?
This is the asexual multiplication in the erythrocytes in the human. These are the blood stages. This stage causes the symptoms and the parasite stays in the red blood cells without a nucleus so it stays hidden from the immune system.
What are the lifecycle steps of the erythrocytic stage of plasmodium?
- These merozoites infect red blood cells and become trophozoites (ring stage)
- The ring stage trophozoites mature into schizonts, which rupture releasing merozoites that can again infect red blood cells.
- Some trophozoites in red blood cells differentiate into sexual erythrotic stages and now are gametocytes
What happens in the Sporogonic cycle of Plasmodium?
The parasites’ multiplication in the mosquito or sexual replication. This takes 9-10 days.
What are the lifecycle steps of the Sporogonic stage of plasmodium?
- The gametocytes, male (microgametocytes) and female (macrogametocytes), are ingested by an anopheles mosquito during a blood meal.
- While in the mosquito’s stomach, the microgametes penetrate the macrogametes generating zygotes (sexual replication)
- The zygotes in turn become motile and elongated and are now ookinetes
- Ookinetes invade the midgut wall of the mosquito where they develop into oocysts
- The oocysts grow, rupture and release sporozoites which make their way up to the mosquito’s salivary glands. Inoculation of the sporozoites into a new human host can start the life cycle again.
What type of life cycle has Plasmodium Falciparum?
Indirect life cycle
What are the definitive and intermediate host for Plasmodium Falciparum?
Human is intermediate host
Mosquito is the definitive host
What are the symptoms of Plasmodium Falciparum infection?
Fever and chills during rupture of red blood cells during the erythrocytic stage accompanied by headache, myalgias, arthralgias, anemia, thrombocytopenia, hypoglycemia, pulmonary or renal dysfunction and neurological changes. All clinical manifestations are caused by the blood stage parasites
Plasmodium falciparum specifically causes the most fatal forms with nervous system involvement (Cerebral malaria), acute renal failure, severe anemia, or acute respiratory distress syndrome. This variant is therefore the most deadly
Where is Plasmodium Falciparum endemic?
Tropical and subtropical areas and altitudes below 1500m.
How is Plasmodium Falciparum diagnosed?
The golden standard is microscopy however this is very difficult, time consuming and expensive. For this you use a thin and thick smear of blood.
It’s also possible to diagnose through molecular diagnosis using species-specific PCR diagnosis. This determines the different species of malaria
In the field through rapid diagnostic tests that detect enzymatic activities associated with the parasite.
Antibody detection is also possible using the indirect fluorescent antibody test (IFA). Making antibodies takes time and is useful for screening blood donors or test treated patients but not to test a sick patient since they will die before antibodies have been made.
