Malaria is a mosquito-borne infectious disease that affects humans and other vertebrates. Human malaria causes symptoms that typically include fever, fatigue, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. Symptoms usually begin 10 to 15 days after being bitten by an infected Anopheles mosquito. If not properly treated, people may have recurrences of the disease months later. In those who have recently survived an infection, reinfection usually causes milder symptoms. This partial resistance disappears over months to years if the person has no continuing exposure to malaria.
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 vertebrate host during a blood meal. Parasites grow within a vertebrate body tissue before entering the bloodstream to infect red blood cells. The ensuing destruction of host red blood cells can result in malaria. During this infection, some parasites are picked up by a blood-feeding insect, continuing the life cycle.
Plasmodium falciparum is a unicellular protozoan parasite of humans, and the deadliest species of Plasmodium that causes malaria in humans. The parasite is transmitted through the bite of a female Anopheles mosquito and causes the disease's most dangerous form, falciparum malaria. It is responsible for around 50% of all malaria cases. P. falciparum is therefore regarded as the deadliest parasite in humans. It is also associated with the development of blood cancer and is classified as a Group 2A (probable) carcinogen.
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 human malaria parasites, P. vivax malaria infections can lead to severe disease and death, often due to splenomegaly. P. vivax is carried by the female Anopheles mosquito; the males do not bite.
Plasmodium malariae is a parasitic protozoan that causes malaria in humans. It is one of several species of Plasmodium parasites that infect other organisms as pathogens, also including Plasmodium falciparum and Plasmodium vivax, responsible for most malarial infection. Found worldwide, it causes a so-called "benign malaria", not nearly as dangerous as that produced by P. falciparum or P. vivax. The signs include fevers that recur at approximately three-day intervals – a quartan fever or quartan malaria – longer than the two-day (tertian) intervals of the other malarial parasite.
Plasmodium knowlesi is a parasite that causes malaria in humans and other primates. It is found throughout Southeast Asia, and is the most common cause of human malaria in Malaysia. Like other Plasmodium species, P. knowlesi has a life cycle that requires infection of both a mosquito and a warm-blooded host. While the natural warm-blooded hosts of P. knowlesi are likely various Old World monkeys, humans can be infected by P. knowlesi if they are fed upon by infected mosquitoes. P. knowlesi is a eukaryote in the phylum Apicomplexa, genus Plasmodium, and subgenus Plasmodium. It is most closely related to the human parasite Plasmodium vivax as well as other Plasmodium species that infect non-human primates.
Malaria culture is a method for growing malaria parasites outside the body, i.e., in an ex vivo environment. Although attempts for propagation of the parasites outside of humans or animal models reach as far back as 1912, the success of the initial attempts was limited to one or just a few cycles. The first successful continuous culture was established in 1976. Initial hopes that the ex vivo culture would lead quickly to the discovery of a vaccine were premature. However, the development of new drugs was greatly facilitated.
Laverania is a subgenus of the parasite genus Plasmodium. Infection with these species results in malaria. The subgenus was first described in 1958.
Malaria vaccines are vaccines that prevent malaria, a mosquito-borne infectious disease which annually affects an estimated 247 million people worldwide and causes 619,000 deaths. The first approved vaccine for malaria is RTS,S, known by the brand name Mosquirix. As of April 2023, the vaccine has been given to 1.5 million children living in areas with moderate-to-high malaria transmission. It requires at least three doses in infants by age 2, and a fourth dose extends the protection for another 1–2 years. The vaccine reduces hospital admissions from severe malaria by around 30%.
The history of malaria extends from its prehistoric origin as a zoonotic disease in the primates of Africa through to the 21st century. A widespread and potentially lethal human infectious disease, at its peak malaria infested every continent except Antarctica. Its prevention and treatment have been targeted in science and medicine for hundreds of years. Since the discovery of the Plasmodium parasites which cause it, research attention has focused on their biology as well as that of the mosquitoes which transmit the parasites.
Pregnancy-associated malaria (PAM) or placental malaria is a presentation of the common illness that is particularly life-threatening to both mother and developing fetus. PAM is caused primarily by infection with Plasmodium falciparum, the most dangerous of the four species of malaria-causing parasites that infect humans. During pregnancy, a woman faces a much higher risk of contracting malaria and of associated complications. Prevention and treatment of malaria are essential components of prenatal care in areas where the parasite is endemic – tropical and subtropical geographic areas. Placental malaria has also been demonstrated to occur in animal models, including in rodent and non-human primate models.
Plasmodium cynomolgi is an apicomplexan parasite that infects mosquitoes and Asian Old World monkeys. In recent years, a number of natural infections of humans have also been documented. This species has been used as a model for human Plasmodium vivax because Plasmodium cynomolgi shares the same life cycle and some important biological features with P. vivax.
Plasmodium billbrayi is a parasite of the genus Plasmodium subgenus Laverania.
Plasmodium gaboni is a parasite of the genus Plasmodium subgenus Laverania.
Plasmodium brasilianum is a parasite that infects many species of platyrrhine monkeys in South and Central America.
The Plasmodium helical interspersed subtelomeric proteins (PHIST) or ring-infected erythrocyte surface antigens (RESA) are a family of protein domains found in the malaria-causing Plasmodium species. It was initially identified as a short four-helical conserved region in the single-domain export proteins, but the identification of this part associated with a DnaJ domain in P. falciparum RESA has led to its reclassification as the RESA N-terminal domain. This domain has been classified into three subfamilies, PHISTa, PHISTb, and PHISTc.
David A. Fidock, is the CS Hamish Young Professor of Microbiology and Immunology and Professor of Medical Sciences at Columbia University Irving Medical Center in Manhattan.
John Massa Kasenene is a botanical and environmental ecologist, academic, scientist and academic administrator in Uganda. From 4 October 2022, he serves as the substantive Deputy Vice Chancellor of the Mountains of the Moon University (MMU), at that time, the tenth public university in the country.
