Origin of Malaria

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QUESTION:

What is the origin of malaria?

ANSWER:

Malaria is caused by a single-celled parasite called Plasmodium; different species cause the different forms of malaria we see in different parts of the world. Malaria has been in existence for millions of years; it likely evolved from similar infections in other apes. Ancient people recognised the symptoms of malaria as early as 2700 BCE, when it was first described in a Chinese medical text. The ancient Romans, Greeks and Egyptians also knew about it, but it wasn’t until the 19th century when the causative agents were first seen in a patient’s blood by a French surgeon called Charles Louis Alphonse Laveran. A few years later, a British Army doctor called Ronald Ross first discovered that the parasites were transmitted via mosquitoes. He won the Nobel Prize for his work in 1902.

Recurring Malaria Long Term Effects

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QUESTION:

Hi, my husband is an expat working in Mozambique for the past 5 years. He has been diagnosed with malaria 9 times, what are the long term effects of this and is he just unlucky or do others also get infected often? thanks.

ANSWER:

If the proper precautions are not taken, then it is very easy to get infected with malaria multiple times; I have one Ugandan colleague who claims he gets sick at least once a year from malaria, usually sometime in the rainy season. However, there are means to protect oneself from regular infection, and it might be that your husband could be more vigilant about such methods of prevention. For example, he should make sure he sleeps under a long-lasting insecticide treated bednet, which drastically reduced the risk of being bitten by mosquitoes at night. Similarly, he should try to wear long trousers and long-sleeved shirts, preferably impregnated with a substance called permethrin (an insecticide which prevents mosquitoes from biting through clothing – it can be purchased at most camping stores and sprayed directly onto clothing only, not onto skin), especially at dawn, dusk and at night, when malaria-carrying mosquitoes are most active. When mosquito numbers are high, he could also use insecticide that contains DEET on any exposed skin as a further precaution against bites.

The good news is that if his previous bouts of malaria have been uncomplicated, and diagnosed and treated quickly, there should be no long term effects of having had the infection.

Treatment for Pregnant Woman with P. Vivax Malaria

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QUESTION:

A pregnant woman has vivax malaria what treatment should be given in case of relapse?

ANSWER:

Primaquine, the usual drug given to prevent relapse of P. vivax malaria, is not recommended for pregnant women due to inadequate information about its safety. As such, it is normally recommended to treat the relapses with chloroquine, to cure each malarial episode, until after delivery of the child, after which time the woman should be treated with primaquine.

How can malaria be controlled?

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QUESTION:

What is malaria? How can it be controlled?

ANSWER:

Malaria is a disease caused by a single-celled parasite called Plasmodium. There are four species that regularly infect humans: P. falciparum (which causes the most severe form of the disease, and is responsible for 90% of the annual 700,000 fatalities caused by malaria, mainly in Africa), P. vivax, P. ovale and P. malariae. A fifth species, P. knowlesi, has recently also been reported in a small number of cases in south-east Asia, where prevalence appears to be increasing.

Despite it’s wide geographic range and potentially severe consequences, there are actually several effective strategies for controlling malaria, many of which have been successful of reducing the burden of the disease, and especially the number of deaths, in various regions. The first step towards control is prevention. This has largely been achieved through the distribution of long-lasting insecticide treated bednets, which prevent people from being bitten by infected mosquitoes as they sleep at night. While this has drastically reduced the number of cases of malaria in some settings, and particularly in certain high risk groups such as children under five and pregnant women, some worrying new data just was published which suggested that in high transmission zones, bednets may actually exacernate re-infection rates for older children and adults, and lead to insecticide resistance in mosquitoes. As such, while bednets clearly are still a key prevention strategy, their effect should be closely monitored.

Secondly, there is diagnosis and treatment. These go hand in hand, as they usually require the availability of health services or health professionals. If malaria infections are rapidly and accurately diagnosed, appropriate treatment can be swiftly given, preventing the progression of the disease and allowing the patient to recover. Appropriate administration of medication, as well as adherence to the full course of the drugs, can also help to prevent drug-resistance from emerging.

Finally, there are on-going research initiatives looking to find new ways to tackle malaria. For example, many scientists are involved in the search for a malaria vaccine, which, if safe, effective, and sufficiently cheap, could transform the way we think about fighting malaria. Similarly, due to the unfortunate circumstance of ever-increasing drug-resistance, particularly in Plasmodium falciparum, new types of medication are constantly being tested and trialled. The combination of all these efforts has managed to reduce the mortality of malaria greatly over the past few years; the aim now, espoused by organisations such as Malaria No More, is to get to a point where deaths from malaria are eliminated by the year 2015.

high fever after malaria is cured?

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QUESTION:

My dad was infected with malaria,and his blood platelets were depleted to 35000. He was immediately admitted to hospital. Now after 5 days of being admitted, he is getting high fever around 102 degrees every morning and evening. His blood platelets have increased to 3lac and all other reports are normal. According to the doctor, the malaria is cured, but they are not able to detect the reason for periodical high fever…is such fever common after malaria? What might be the reason? Please help.

ANSWER:

One of our collaborating medical doctors has kindly assisted in providing this answer. Fever can be from co-infection with a second strain/type of malaria, or from the drug being used to treat the malaria.  If his platelets were that low, then the likely type of malaria causing the infection would be Plasmodium falciparum, or a particularly heavy P. vivax burden, or infection with both. If he was/is in the hospital, other causes for fever could also be the IV line/another drug being given, complications such as pneumonia from being at bedrest or so ill, cholecystitis from not eating due to illness, DVT or blood clots in legs from immobility….there are many possibilities. More information would be needed to distinguish between these options.

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.