Plasmodium falciparum

Plasmodium falciparum is a protozoan parasite, one of the species of Plasmodium that cause malaria in humans. It is transmitted through the bite of an infected female Anopheles mosquito. P. falciparum is the most severe and deadly form of malaria, leading to the disease known as falciparum malaria. It is responsible for the majority of malaria-related deaths globally and is most prevalent in the tropical and subtropical regions of Sub-Saharan Africa, Southeast Asia, and South America.

Life Cycle

The life cycle of Plasmodium falciparum involves two hosts: the human and the Anopheles mosquito. In humans, the infection begins when an infected mosquito injects Plasmodium sporozoites into the bloodstream. The sporozoites travel to the liver, where they infect hepatocytes and multiply asexually. After several days, the parasites emerge from the liver as merozoites, which then infect red blood cells. Inside the red blood cells, the parasites multiply again, leading to the bursting of the cells and the release of more merozoites into the bloodstream. This cycle of red blood cell infection, multiplication, and rupture is responsible for the clinical symptoms of malaria.

In the mosquito, when it feeds on an infected human, it ingests gametocytes along with the blood. In the mosquito's gut, the gametocytes mature into male and female gametes that fuse to form zygotes. The zygotes then develop into motile ookinetes that penetrate the mosquito's gut wall and form oocysts. Inside the oocysts, sporozoites develop and are eventually released into the mosquito's salivary glands, ready to infect another human host.

Clinical Features

Falciparum malaria is characterized by high fever, chills, flu-like symptoms, anemia, and in severe cases, cerebral malaria. Cerebral malaria is a life-threatening condition where infected red blood cells adhere to the vascular endothelium in the brain, leading to coma and, if untreated, death. Other severe complications include acute respiratory distress syndrome (ARDS), kidney failure, and severe anemia.

Diagnosis and Treatment

Diagnosis of falciparum malaria is typically made by microscopic examination of blood smears, which can reveal the presence of Plasmodium parasites within red blood cells. Rapid diagnostic tests (RDTs) that detect antigens derived from the parasites are also widely used.

Treatment involves antimalarial medications, with artemisinin-based combination therapies (ACTs) being the most effective against P. falciparum. In cases of severe malaria, intravenous administration of antimalarials is necessary. Prompt treatment is crucial to prevent severe complications and death.

Prevention

Prevention of falciparum malaria includes the use of mosquito control measures such as insecticide-treated bed nets, indoor residual spraying, and environmental management to reduce mosquito breeding sites. Personal protective measures, such as the use of insect repellent and wearing long-sleeved clothing, are also important. In areas with high transmission rates, intermittent preventive treatment in pregnancy (IPTp) and in infants (IPTi) can reduce the risk of severe disease in these vulnerable populations.