Plasmodium malariae

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.

History

Malaria has been recognized since the Greek and Roman civilizations over 2,000 years ago, with different patterns of fever described by the early Greeks. In 1880, Alphonse Laveran discovered that the causative agent of malaria is a parasite.]]

Each year, approximately 500 million people will be infected with malaria worldwide. Of those infected, roughly two million will die from the disease. Malaria is caused by six Plasmodium species: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale curtisi, Plasmodium ovale wallikeri, Plasmodium malariae and Plasmodium knowlesi.

thumb|Geographical areas of malaria transmission

P. malariae is the least studied of the six species that infect humans, in part because of its low prevalence and milder clinical manifestations compared to the other species. It is widespread throughout sub-Saharan Africa, much of southeast Asia, Indonesia, on many of the islands of the western Pacific and in areas of the Amazon Basin of South America. but there is evidence that P. malariae infections are vastly underreported.

The Centers for Disease Control (CDC) has an application that allows people to view specific parts of the world and how they are affected by Plasmodium vivax, and other types of the Plasmodium parasite. It can be found at the following link: http://cdc.gov/malaria/map/index.html.

Role in disease

P. malariae can infect several species of mosquito and can cause malaria in humans.

Diagnostics

The preferable method for diagnosis of P. malariae is through the examination of peripheral blood films stained with Giemsa stain.

Human infection

Liver stage and blood stage

In the liver stage, many thousands of merozoites are produced in each schizont.

At the schizont stage, after schizogonic division, there are roughly 6–8 parasite cells in the erythrocyte. This subsequently leads to the cycle in the human liver. Given the slower pre-erythrocytic development and longer incubation period compared to the other malaria causing Plasmodium species, the researchers hypothesized that the anti-malarials may not be effective enough against the pre-erythrocytic stages of P. malariae. In that event, it is possible that the results from Müller-Stöver et al. provided isolated incidences.

Public health, prevention strategies and vaccines

The food vacuole is the specialized compartment that degrades hemoglobin during the asexual erythrocytic stage of the parasite.

The continuing work with the plasmepsin associated with P. malariae, plasmepsin 4, by Professor Ben Dunn and his research team from the University of Florida may provide hope for long term malaria control in the near future.

Genome

In 2017 the full genome was published. The sequences can be accessed on geneDB.org and plasmoDB.org.