What is malaria?

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QUESTION:

What is 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 characterize malaria infection episodes.

What pathogenic organisms cause malaria?

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QUESTION:

What pathogenic organism causes the disease?

ANSWER:

Malaria is caused by single-celled organisms, called protozoans, of the genus Plasmodium. Different forms of malaria are caused by different species of Plasmodium. The most severe and deadly form is caused by P. falciparum, which is responsible for 90% of the global deaths from malaria, the majority of these in Africa, and mostly in young children. Other species of Plasmodium which commonly infect humans include P. vivax, P. ovale and P. malariae. Recently, a fifth form, P. knowlesi, has been found infecting rural communities in south-east Asia.

The disease is caused when the parasite enters the patient’s red blood cells, reproduces rapidly and then bursts out of the cell, destroying it in the process. The resultant immune response, combined with the chemicals and debris produced by theparasites, induces the fever, nausea, aches and other symptoms of a malaria infection.

Who discovered the disease malaria?

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QUESTION:

Who discovered the malaria disease and when?

ANSWER:

Malaria has been known for thousands of years; there are written accounts of the disease, including a description of its symptoms, in ancient Chinese medical texts from 2700 BCE. The ancient Romans and Greeks also knew about malaria.

However, the causes of the disease were only discovered in the 19th century. In 1880, a French surgeon called Charles Louis Alphonse Laveran stationed in Algeria was the first person to see the parasites that cause malaria in the blood of an infected person. Then, a few years later, in 1897/1898, a British army doctor called Ronald Ross discovered that mosquitoes transmitted the parasites between patients. This allowed for further clarification of the life cycle of malaria, and thus opened up the path for modern malaria research and control.

Malaria and Jaundice

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QUESTION:

Why are patients suffering with malaria more susceptible to jaundice?

ANSWER:

The icterus/jaundice is usually from lysis/breakdown of infected red blood cells as they rupture and release new malaria parasites into the bloodstream.  If only 1% of red cells are infected, this will be mild.  If “parasitaemia” is severe/life threatening, say, 10% of red cells infected, then the jaundice will be dramatic as well as a risk for catastrophic organ failure from cell breakdown, iron deposition into capillaries/small blood vessels in brain/kidneys/liver. In such cases, exchange blood transfusion could be life-saving.


Malaria Locations in Africa

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QUESTION:

Where in Africa is malaria mainly found?

ANSWER:

The distribution of malaria is constrained by two main factors: temperature and the presence of suitable mosquito hosts. These mosquitoes also depend on certain climatic conditions for their development, namely warm temperatures and sufficient rainfall to produce stagnant water, required by mosquito larvae. As such, although most of Africa lies within latitudes that would normally produce warm enough temperatures for at least seasonal transmission of malaria, in fact the disease is not found everywhere.

spatial distribution Plasmodium falciparum malaria Africa
Spatial distribution of Plasmodium falciparum malaria in Africa. From Hay et al., 2009, “A world malaria map: Plasmodium falciparum endemicity in 2007”, PLoS Medicine 6(3)

Winters in the Mediterranean region and most of the Cape are too cold for malaria, and in these areas, control interventions have largely eliminated the risk of summer sporadic transmission. Similarly, at high elevations, temperatures are too low for the development of the parasite and/or the mosquito vector. For this reason, places such as central Zimbabwe, the high plateau of Ethiopia and even large cities like Nairobi are relatively malaria-free. Finally, the Sahara and Kalahari desert regions are too dry – there is insufficient moisture for the survival of the mosquito vectors.

Based on these factors, the hotspots for malaria transmission in Africa lie in lowland areas with moderate to high rainfall. The map above shows the distribution of Plasmodium falciparum, the most severe and deadly form of the disease.

How quickly should patient take medicine for malaria?

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QUESTION:

My sister has been suffering from malaria for three months. She consulted with doctor in the first symptom of malaria but doctor gave only fever medicine at that time. Blood test was not done at that time. So my question is: “within how many days or months malaria patient has to immediately take medicine?”

ANSWER:

One of our collaborating medical doctors has assisting in providing this answer:

It depends on the type of malaria….with Plasmodium vivax infection she could have a low burden due to concurrent treatment or recent prophylaxis which is breaking through because of low grade resistance. Alternatively, it could be P. malariae or P. ovale, both of which sometimes cause only mild disease that may or may not progress.  P. falciparum shouldn’t act this way; it is usually a much more severe, aggressive infection. Another option is that she might not have malaria at all.  She needs qualitative and quantitative smears to confirm the diagnosis, together with a comprehensive travel/exposure history to support any clinical suspicions.

 

 

Malaria and stomach pains

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QUESTION:

Will malaria cause severe stomach pain?

ANSWER:

In some cases, yes, malaria can cause stomach cramps and pain. It also often causes nausea and vomiting. It is important to seek medical attention if you think you have symptoms of malaria; a quick and accurate diagnosis will lead to effective and efficient treatment, which improves chances of a rapid recovery.

Malaria Control in Developing Countries

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QUESTION:

Should malaria be controlled in third world countries?

ANSWER:

Absolutely! Malaria is a leading cause of preventable death in many developing countries, with young children (under the age of five) at particular risk. Moreover, malaria is linked to loss of productivity, absenteeism from work/school and may even be linked to continuing cycles of poverty in areas where malaria (and other tropical diseases) are endemic. As such, malaria is implicated in at least four of the Millenium Development Goals.

Many organisations are working together with the governments of developing countries in order to combat malaria and other diseases. With widespread measures for malaria prevention (such as the distribution of long-lasting insecticide treated bednets), diagnosis and treatment, it is hoped that the burden of malaria, and especially mortality, will be reduced.

Why are platelets low in malaria infections?

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QUESTION:

Why are platelets low in malaria infections? Why is there no internal bleeding in malaria?

ANSWER:

Platelets are low especially with P. falciparum infections, but also potentially with high-burden P. vivax infections. This is probably from sequestration in blood vessels and spleen. Actually, there is life threatening bleeding associated with severe cerebral malaria from this stasis and sequestration in the brain. Similarly, enlargement of the spleen leaves it susceptible to rupture, which would lead to critical internal bleeding.