Malaria is a mosquito-borne infectious disease that affects vertebrates and Anopheles mosquitoes. 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. The mosquito vector is itself harmed by Plasmodium infections, causing reduced lifespan.
Ferrocene is an organometallic compound with the formula Fe(C5H5)2. The molecule is a complex consisting of two cyclopentadienyl rings sandwiching a central iron atom. It is an orange solid with a camphor-like odor that sublimes above room temperature, and is soluble in most organic solvents. It is remarkable for its stability: it is unaffected by air, water, strong bases, and can be heated to 400 °C without decomposition. In oxidizing conditions it can reversibly react with strong acids to form the ferrocenium cation Fe(C5H5)+2. Ferrocene and the ferrocenium cation are sometimes abbreviated as Fc and Fc+ respectively.
Antimalarial medications or simply antimalarials are a type of antiparasitic chemical agent, often naturally derived, that can be used to treat or to prevent malaria, in the latter case, most often aiming at two susceptible target groups, young children and pregnant women. As of 2018, modern treatments, including for severe malaria, continued to depend on therapies deriving historically from quinine and artesunate, both parenteral (injectable) drugs, expanding from there into the many classes of available modern drugs. Incidence and distribution of the disease is expected to remain high, globally, for many years to come; moreover, known antimalarial drugs have repeatedly been observed to elicit resistance in the malaria parasite—including for combination therapies featuring artemisinin, a drug of last resort, where resistance has now been observed in Southeast Asia. As such, the needs for new antimalarial agents and new strategies of treatment remain important priorities in tropical medicine. As well, despite very positive outcomes from many modern treatments, serious side effects can impact some individuals taking standard doses.
Artemisinin and its semisynthetic derivatives are a group of drugs used in the treatment of malaria due to Plasmodium falciparum. It was discovered in 1972 by Tu Youyou, who shared the 2015 Nobel Prize in Physiology or Medicine for her discovery. Artemisinin-based combination therapies (ACTs) are now standard treatment worldwide for P. falciparum malaria as well as malaria due to other species of Plasmodium. Artemisinin is extracted from the plant Artemisia annua an herb employed in Chinese traditional medicine. A precursor compound can be produced using a genetically engineered yeast, which is much more efficient than using the plant.
Chloroquine is an antiparasitic medication that treats malaria. It works by increasing the levels of haeme in the blood, a substance toxic to the malarial parasite. This kills the parasite and stops the infection from spreading. Certain types of malaria, resistant strains, and complicated cases typically require different or additional medication. Chloroquine is also occasionally used for amebiasis that is occurring outside the intestines, rheumatoid arthritis, and lupus erythematosus. While it has not been formally studied in pregnancy, it appears safe. It was studied to treat COVID-19 early in the pandemic, but these studies were largely halted in the northern summer of 2020, and the NIH does not recommend its use for this purpose. It is taken by mouth.
Primaquine is a medication used to treat and prevent malaria and to treat Pneumocystis pneumonia. Specifically it is used for malaria due to Plasmodium vivax and Plasmodium ovale along with other medications and for prevention if other options cannot be used. It is an alternative treatment for Pneumocystis pneumonia together with clindamycin. It is taken by mouth.
Proguanil, also known as chlorguanide and chloroguanide, is a medication used to treat and prevent malaria. It is often used together with chloroquine or atovaquone. When used with chloroquine the combination will treat mild chloroquine resistant malaria. It is taken by mouth.
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 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 prophylaxis is the preventive treatment of malaria. Several malaria vaccines are under development.
Malaria vaccines are vaccines that prevent malaria, a mosquito-borne infectious disease which affected an estimated 249 million people globally in 85 malaria-endemic countries and areas and caused 608,000 deaths in 2022. 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%.
Haemozoin is a disposal product formed from the digestion of blood by some blood-feeding parasites. These hematophagous organisms such as malaria parasites, Rhodnius and Schistosoma digest haemoglobin and release high quantities of free heme, which is the non-protein component of haemoglobin. Heme is a prosthetic group consisting of an iron atom contained in the center of a heterocyclic porphyrin ring. Free heme is toxic to cells, so the parasites convert it into an insoluble crystalline form called hemozoin. In malaria parasites, hemozoin is often called malaria pigment.
The administration of drugs to whole populations irrespective of disease status is referred to as mass drug administration (MDA) or mass dispensing.
Piperaquine is an antiparasitic drug used in combination with dihydroartemisinin to treat malaria. Piperaquine was developed under the Chinese National Malaria Elimination Programme in the 1960s and was adopted throughout China as a replacement for the structurally similar antimalarial drug chloroquine. Due to widespread parasite resistance to piperaquine, the drug fell out of use as a monotherapy, and is instead used as a partner drug for artemisinin combination therapy. Piperaquine kills parasites by disrupting the detoxification of host heme.
Arterolane, also known as OZ277 or RBx 11160, is an antimalarial compound marketed by Ranbaxy Laboratories. It was discovered by US and European scientists coordinated by the Medicines for Malaria Venture (MMV). Its molecular structure is uncommon for pharmacological compounds in that it has both an ozonide (trioxolane) group and an adamantane substituent.
Pregnancy-associated malaria (PAM) or placental malaria is a presentation of malaria in pregnancy which is life-threatening to both pregnant women and unborn fetuses. PAM occurs when a pregnant woman contracts malaria, generally as a result of Plasmodium falciparum infection, and because she is pregnant, is at greater risk of associated complications such as placental malaria. Placental malaria interferes with the transmission of vital substances through the fetal placenta, which can result in stillbirths, miscarriages, and dangerously low birth weights.
Ganaplacide is a drug in development by Novartis for the purpose of treating malaria. It is a imidazolopiperazine derivative. It has shown activity against the Plasmodium falciparum and Plasmodium vivax forms of the malaria parasite.
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.
Gallinamide A is potent and selective inhibitor of the human cysteine protease Cathepsin L1 that was first used as a moderate antimalarial agent. Gallinamide A is produced by marine cyanobacteria from Schizothrix species and Symploca sp. which have also shown to have possible anticancer agent, infectious diseases like leishmaniasis, trypanosomiasis and possible uses in Alzheimer's disease, among others.
Norketotifen is a pharmaceutical medication which is not yet approved for use and is undergoing clinical trials. It is a biologically active demethylated metabolite of ketotifen and has a similar potency as ketotifen as an antihistamine H1 medication and a mast cell stabilizer, yet is devoid of severe sedative effects of ketotifen, potentially allowing for higher doses to be administered without sedation as a limiting factor. Norketotifen is researched for its potential anti-inflammatory activity caused by dose-dependent inhibition of the release of the pro-inflammatory cytokine TNF-α, and for its other potential properties.
