Target Species
Background
Malaria is caused by protozoan parasites of the genus Plasmodium, unicellualr eukaryotes that are unable to survive outside of their host/vector.
There are 5 species known to infect humans:
- Plasmodium falciparum, is responsible for the majority of malaria deaths globally and is the most prevalent species in sub-Saharan Africa. Further information can be found on the P. falciparum Species Page.
- Plasmodium vivax, is the second most significant species and is prevalent in Southeast Asia and Latin America. It has the added complication of a dormant liver stage (hypnozoite), which can be reactivated in the absence of a mosquito bite, leading to clinical symptoms. Further information can be found on the P. vivax Species Page.
- Plasmodium ovale, represents only a small percentage of infections but is the second most common species in sub-Saharan Africa (after P. falciparum). It is biologically and morphologically very similar to P. vivax, including a dormant liver stage. However, unlike P. vivax, it can infect individuals who do not express the Duffy antigen (ACKR1) on the erythrocyte cell surface. This may account for the greater prevalence of P. ovale (rather than P. vivax) in most of Africa where the Duffy-null blood group predominates.
- Plasmodium malariae, is responsible for only a small percentage of reported infections and is found worldwide. P. malariae causes mild clinical symptoms but if left untreated can progress to a long-lasting, chronic infection that may lead to serious complications such as nephrotic syndrome. It is the only Plasmodium species, with a natural human host, that has a quartan (three-day) rather than a tertian (two-day) cycle of asexual replication.
- Plasmodium knowlesi, is becoming a significant cause of zoonotic malaria and an emerging public health issue in Southeast Asia (PMID:26817785). Species of macaque monkey are the natural host and the exact mode of transmission to humans is unclear. P. knowlesi has a 24-hour asexual replication cycle in erythrocytes and can progress quickly to severe clinical disease with fatal cases reported.
There are also a number of species that infect mammals other than humans and that are used extensively as models of human malaria.
- Four different species that infect Central African rodents (thicket rats) have been adapted for laboratory use: Plasmodium berghei, Plasmodium yoelii, Plasmodium chabaudi and Plasmodium vinckei. Small differences exist in the biology of these species, allowing different aspects of human malaria to be investigated.
- Plasmodium cynomolgi, a species that infects non-human primates (Asian Old World monkeys are the natural mammalian host), is also used in malaria research. It is used as a model for human P. vivax infection because these species are phylogenetically close and share a similar lifecycle, including the dormant liver form.
Target Species Data
The Guide to MALARIA PHARMACOLOGY includes species information for antimalarial ligands and their target interactions. Click on a species name below to view an individual page that includes a detailed species description and a list of the target and ligand associations contained in the database.
Resources
The European Malaria Reagent Repository, established from the former P. falciparum and mouse Plasmodia resources of the WHO malaria parasite repository, with the aim of collecting and providing malaria-related research reagents, materials and standard operating protocols.
The Malaria Research and Reference Reagent Resource Center (MR4), developed by the National Institute of Allergy and Infectious Diseases (NIAID) to provide a centralised resource for malaria-related research reagents.
RMgmDB, a repository containing information on genetically modified rodent malaria parasites.
P. vivax Information Hub, offering knowledge and guidance on replasing P. vivax malaria. Contains key learnings, best practices, tools and resources from a consortium of stakeholders involved in the treatment and control of P. vivax malaria.
