Deadliest Malaria Parasite

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QUESTION

which malarial parasite is deadliest for humans, and why?

ANSWER

By far the most deadly malaria parasite is Plasmodium falciparum, as it is responsible for >95% of all malaria deaths every year. Most of these fatalities occur in young children in sub-Saharan Africa.

The causes for why P. falciparum is so deadly are still not fully understood. This parasite has the ability to cause infected red blood cells to become “sticky”, and therefore clog up small blood vessels called capillaries inside the body’s organs. This process is known as “sequestration”. Sequestration reduces blood flow to major organs, resulting in a variety of secondary conditions, perhaps the most famous well-recognized of which is so-called “cerebral malaria”, where oxygen flow to the brain is reduced and as a result of this and other effects of sequestration, impaired consciousness, coma and even death can occur.

Who introduced malaria in which century?

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QUESTION

Who introduced malaria in which century, how does it cause malaria and what is the virus’ name?

ANSWER

Malaria wasn’t introduced; it has been evolving alongside humans for thousands, if not millions of years. The first known mention of malaria by humans is in an ancient Chinese medical text, from 2700 BCE (before common era). Other ancient people, such as the Romans and the Greeks, knew the symptoms of malaria and described it in writing.

Malaria is actually not caused by a virus, but a single-celled animal called a protozoan. The genus name of the protozoans that cause malaria is Plasmodium, and there are five main species that infect humans: P. falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi.

The malaria parasites cause the disease by entering into red blood cells and multiplying; when they have reproduced, they burst out of the red blood cell, destroying it. The patient’s blood is therefore rapidly full of malaria parasites, their waste products, plus bits of destroyed red blood cell; this produces an extreme immune reaction which causes many of the symptoms of malaria. In infection with P. falciparum, the most deadly and severe kind, infection with the parasite causes red blood cells to sequester in tiny red blood cells within major organs, causing reduced oxygen flow and complications. When this occurs in the brain, the result is cerebral malaria, which can result in convulsions and even a coma.

Malaria and Renal Failure

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QUESTION

Explain how malaria can cause renal failure?

ANSWER

There are several mechanisms by which malaria can contribute to renal failure, which vary due to the type of malaria. The exact way in which these various effects combine to cause acute renal failure is not known.

The most common type of malaria to cause renal failure is Plasmodium falciparum, generally the most severe and deadly form of the disease. P. falciparum infected red blood cells are known to sequester in tiny red blood cells deep within major organs, including the kidney; it is thought that reduced blood flow and resulting lack of oxygen may contribute to renal failure. Exaggerated immune response to infection may also be a major contributor to renal failure—this is most likely to cause of renal complications seen in other forms of malaria infection, such as Plasmodium malariae infection.

Moreover, acute renal failure is more usually observed in non-immune adults to malaria (such as those who did not grow up in malaria areas) or older children, again suggesting an involvement of the immune response. Finally, dehydration, associated with a lack of sufficient fluid intake during illness with malaria, may compound these other issues, and contribute to renal failure. Perhaps counterintuitively, administration of intravenous fluids may actually worsen the system, due to the body’s shock-like response to the sudden increase in fluids.

Malaria and Blood Cells

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QUESTION

What effect does malaria have on blood cells?

ANSWER

Malaria survives by invading red blood cells (erythrocytes), then replicating within them several times (the exact number and timing of replication depends on the species of malaria), then, once done with replication, bursts from inside the red blood cells, destroying it in the process. As such, malaria infection decreases the number of red blood cells in a patient’s blood, which can lead to anaemia. Moreover, the most severe species of malaria, Plasmodium falciparum, forces red blood cells to stick to the insides of tiny blood vessels deep within major organs such as the kidneys and even brain. This process is called sequestration.

Infection with malaria is also often associated with a decrease in the overall number of white blood cells, but elevated numbers of monocytes can sometimes be observed.

Why do people die of malaria?

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QUESTION:

Why is it that people die of malaria?

ANSWER:

The symptoms of malaria are caused by the malaria parasite reproducing inside the patient’s red blood cells and eventually destroying them. In this process, the malaria parasites also produce toxic waste chemicals and debris which build up in the patient’s blood stream. The body produces a strong immune response as a reaction to these toxic products and debris; most of the systemic symptoms associated with malaria, such as fever, aching muscles and joints and nausea, are related to this immune response. Infected red blood cells can also build up in internal organs, notably the spleen and the liver, causing them to swell.

Despite these nasty-sounding effects, most cases of malaria are relatively benign and don’t lead to death. However, in some cases, the manifestation of the disease can become more severe. Most commonly, this occurs when a patient is infected with Plasmodium falciparum, one of the four main kinds of malaria that infect humans, and by far the most severe. P. falciparum reproduces very rapidly in the human host, causing extremely high fever and a fast onset of symptoms. It also changes the structure of the red blood cells it infects, causing them to become “stuck” deep within tiny blood vessels and especially in major organs such as the brain, intestines, liver, heart and lungs. Stuck within these blood vessels, the infected red blood cells are effectively hidden from the immune system and are not cleared from the body via the spleen. This allows the malaria parasite’s reproduction to go unchecked, resulting in very high numbers of the parasite in the patient’s blood.

If left untreated, the build-up of infected red blood cells can result in severe anaemia, reduced local oxygen flow and the blocking of the immune reaction; the exact mechanisms are not fully understood. When these processes occur in the brain, the result is so-called “cerebral malaria”, characterised by impaired consciousness, and which can lead to convulsions, coma and death. Even if a patient recovers from the disease episode, they may be left with permanent neurological damage. Luckily, malarial comas are often rapidly reversed after treatment is administered, and in many cases, neurological damage is not permanent.

Can malaria cause kidney failure?

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QUESTION:

Can malaria be a cause for kidney failure or brain fever?

ANSWER:

Malaria, and specifically Plasmodium falciparum malaria, the most severe and deadly form of the disease, can certainly cause both renal failure and brain fever. It usually does this by infecting red blood cells, which then become blocked in tiny blood vessels deep within organs. This process is called sequestration. When sequestration happens in the brain, the effect can be so-called “cerebral malaria” or brain fever. In the kidney, this can result in kidney failure. Given these severe consequences, it is crucially important to seek diagnosis and then treatment immediately if you are concerned you might be suffering from malaria.

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.