Causes of malaria

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QUESTION:

What are the causes of malaria?

ANSWER:

Malaria is caused by parasites of the genus Plasmodium. These are single-celled animals known as protozoans (from the Greek ‘protos’ and ‘zoia’ which together mean ‘first animal’) and they are transmitted via mosquitoes that feed on blood; the parasites need both mosquito and human hosts to complete their life cycle (see below a graphic of the complete life cycle, courtesy of CDC). In the process of reproducing, the malaria parasites destroy human red blood cells, which is what causes the clinical symptoms of disease that the patient experiences, such as fever, headaches and nausea.

Malaria life cycle CDC

Generalized malaria life cycle (courtesy of CDC: www.cdc.gov)

There are four main species of Plasmodium that infect humans: P. falciparum, P. vivax, P. malariae and P. ovale. P. falciparum causes the most severe manifestations of the disease and is responsible for the majority of human deaths from malaria. There is a fifth type of malaria, P. knowlesi, which usually infects macaque monkeys but has been known to pass into humans as well.

For more on this, please see Christina Faust’s excellent blog post about her research.

Is malaria caused by a dietary absence?

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QUESTION:

Is malaria caused by the absence of one of the following in diet: bacteria, virus, fungi, protozoa?

ANSWER:

If I understand your question correctly, you are asking if malaria is caused by the absence of a particular organism from a person’s diet—in fact, malaria is caused by a protozoan, but infection is not linked to a person’s diet. Instead, people are infected with the protozoans (small, single-celled organisms—in the case of malaria, they belong to the genus Plasmodium) when a mosquito feeds on the person’s blood. The malaria parasites are present in the mosquito’s saliva gland, and enter the human bloodstream as the mosquito is drinking. When a mosquito feeds on a person already infected with malaria, it picks up malaria parasites in the blood it takes in. This is how malaria is transmitted, in the vast majority of cases.

Causes of Malaria

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QUESTION:

What causes malaria?

ANSWER:

Malaria is a disease caused by a parasitic single-celled animal known as Plasmodium. There are different species of Plasmodium, which cause different kinds of malaria. The main types which infect humans are P. falciparum, P. vivax, P. ovale and P. malariae. The parasite is transmitted by certain species of mosquito; the parasite lives in the human blood stream and so goes in to the mosquito when the insect feeds. When the same individual mosquito then feeds on another person, it transmits parasites into a new host.

The symptoms of malaria are caused by the actions that the parasite undertakes while in the human host. For example, part of its reproductive cycle involves invading and then multiplying inside red blood cells. Once several cycles of reproduction have occurred, the new parasites burst out of the red blood cell, destroying it. The cycles are times so that all the new parasites burst out of the red blood cells at the same time; this coordinated destruction of the red blood cells, either every 24, 48 or 72 hours, depending on the malaria species, causes the one day, two day or three day cycles of fevers and chills that characterise malaria infection episodes.

What is malaria?

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QUESTION:

What is malaria?

ANSWER:

Malaria is a disease caused by parasites of the genus Plasmodium. Transmitted by mosquitoes, there are several different kinds of malaria distributed throughout the tropical and sub-tropical regions of the world, causing somewhere between 300-500 million cases of disease each year, and as many as 1 million deaths. In fact, malaria is one of the biggest killers of children under the age of five in sub-Saharan Africa, one of the regions of the world where the burden from malaria is the highest. Malaria is usually an acute disease, manifesting itself with severe fever, chills, headache and often nausea as well. Some types of malaria can have relapsing episodes over a time period of many years.

Having said this, malaria is easily preventable, through avoiding mosquito bites by wearing appropriate clothing and sleeping under insecticide-treated bednets, or through taking preventative medication (called prophylaxis). Malaria is also treatable once symptoms appear, through ingesting safe, effective and relatively cheap drugs. With such control measures at hand, you may ask why malaria is still such a huge problem in our world; the answer is that delivering control strategies and treatment to populations most at risk is difficult, and often countries with high malaria burdens don’t have efficient and effective health systems in place to coordinate control efforts.

International non-governmental organisations such as the World Health Organisation, as well as a multitude of non-profit organisations such as the Malaria Consortium and Malaria No More, work tirelessly to bring malaria control and treatment to the places that need it most, with the aim to eradicate malaria as a disease of public health importance.