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.

Malaria symptoms

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QUESTION:

When a person is ill he or she will have what symptoms?

ANSWER:

Malaria can have many different symptoms, but the initial signs are similar to a flu-like illness, with high fever, chills, headache and muscle soreness or aches. A characteristic sign of malaria is cyclical fever, with peaks of severity every two or three days. Additionally, some people will experience nausea, coughing, vomiting and/or diarrhea.

Because these symptoms are quite generic of a wide variety of illnesses, if you live in a malaria-endemic region, it is crucial to be tested when you develop such symptoms, rather than assuming it’s just the flu and soldiering on! If you have recently traveled to a malarial area and start to experience these signs of infection, similarly you should inform your doctor of your travel history, as otherwise they might not recognize your symptoms as potentially that of malaria.

If treated rapidly and with the correct medication, malaria is almost always completely treatable; it is only if treatment is delayed that it becomes more serious, with long-lasting and potentially fatal consequences. Similarly, if you take sensible precautions while living or traveling in malarial areas, such as taking prophylaxis (and taking them as per the instructions, for the full required amount of time!), avoiding being bitten by mosquitoes and sleeping under an insecticide-treated bed-net, you vastly reduce your chances of getting infected in the first place.

It’s also worth noting that different species of Plasmodium, the parasite that causes malaria, cause slightly different manifestations of the disease, and also require different forms of treatment. Plasmodium falciparum has a unique way of affecting the red blood cells it infects, which eventually can result in loss of function of internal organs. ‘Cerebral malaria’ is a particularly deadly version of this, whereby the function of the brain is affected. The cycles of fever, mentioned above, are caused by synchronous rupturing of the red blood cells in the body by the malaria parasite; P. falciparum, P. vivax and P. ovale complete this cycle every 48 hours, resulting in fever cycles of roughly two days (though P. falciparum can be unpredictable); P. malariae, on the other hand, has a cycle lasting 72 hours, so three day cycles of fever are expected. Finally, although many types of malaria can be successfully treated with the drug chloroquine, some strains, and notably of P. falciparum, have become resistant to this treatment. In these cases, artemesinin-based treatment is recommended, usually in combination with other therapies (artemesinin-combination therapy, or ACT). P. vivax, in addition, requires an additional drug, called primaquine, which is used to treat lingering liver stages of the parasite, to prevent recurrence of the infection.

Malaria Treatment

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QUESTION:

Is there any treatment for malaria?

ANSWER:

Yes, treatment is available for malaria and most cases can be cured easily if diagnosed accurately and early. There are several different drugs that are used to treat malaria, and different modes of ingestion.

Most cases of malaria can be treated effectively with oral drugs, usually artemisinin-based combination therapies (which contain a drug called artemisinin, long used in Chinese medicine to treat malaria) or chloroquine. The choice between these will depend on the type of malaria you have (hence the need for accurate diagnosis) as well as whether the area you are in is known to have types of malaria that are resistant to chloroquine. In addition, some types of malaria, notably P. vivax and P. ovale, require an additional drug, known as primaquine, to prevent later relapses of malaria from dormant forms of the parasite, that hide in the liver.

Severe malaria may require the administration of drugs directly into the body, usually intravenously. Quinine is often the first-choice drug at this stage, though artemisinin-based compounds have also been shown to be effective. Severe malaria, sometimes manifesting as cerebral malaria, is usually only caused by P. falciparum, the most deadly of the types of malaria found in humans.

Does malaria affect population vigour?

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QUESTION:

How is malaria affecting population vigour at present?

ANSWER:

If I understand your question correctly, you are asking if malaria affects the well-being of populations. In answer, malaria is an extremely debilitating disease in many populations around the world, and is known to severely affect population vigour.

People infected with malaria are likely to miss work or school, and of course are at risk of dying from the disease as well. There is, moreover, an intimate association between malaria and poverty, with malaria both being considered a disease caused by poverty as well as a cause of it – malaria is known to result in lost productivity through absenteeism, permanent neurological damage caused by severe disease episodes, and changes in economic or investment decisions based on presence of malaria.

One estimate is that a combination of the above indirect costs of malaria, together with direct costs on the healthcare infrastructure, cost Africa as much as $12 billion per year in lost economic output. A review on the link between poverty and malaria was written in 2002 by Jeffrey Sachs and Pia Malaney for the scientific journal Nature.

(full access to the content may depend on subscription).

How long has malaria existed?

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QUESTION:

How long has malaria been going on?

ANSWER:

The answer to your question depends on the kind of malaria as well as how exactly you define ‘malaria’. The parasites which cause all forms of malaria, in humans as well as other mammals and birds, belong to a group called Plasmodium; scientists believe, based on genetic information, that this genus evolved around 130 million years ago, which is before the dinosaurs went extinct! These ancient ‘malaria’ parasites probably infected lizards; some types of malaria still infect reptiles today.

Plasmodium parasites have since evolved to infect primates, including humans; some scientists argue that this ‘jump’ has probably occurred several times in evolutionary history, whereas other suggest it has only happened once; the debate on this will likely continue for some time!

In terms of when human malaria first evolved, the four main types of malaria that infects humans are P. vivax, P. malariae, P. ovale and P. falciparum; the first three likely either co-evolved with humans or at least first became associated with infecting humans very soon after anatomically modern humans evolved. This dates these types of malaria back to the Middle Stone Age, which started around 300,000 years ago in Africa.

P. falciparum, on the other hand, probably crossed over much more recently, and the most up-to-date genetic evidence suggests that it evolved from a type of malaria which is found in gorillas. Estimates for when this transfer occurred are shaky at best, but it might have only been in the region of 10,000 years ago.

For more reading on the debate regarding the origin and evolutionary histories of Plasmodium as a whole and human forms of malaria more specifically, the following scientific articles may be a good place to start:

Joy, DA; Feng X, Mu J, Furuya T, Chotivanich K, Krettli AU, Ho M, Wang A, White NJ, Suh E, Beerli P & Su XZ, (2003). ‘Early origin and recent expansion of Plasmodium falciparum’, Science 300 (5617): 318–21

Liu, W; Y Li, GH Learn, RS Rudicell, JD Robertson, BF Keele, JN Ndjango, CM Sanz, DB Morgan, S Locatelli, MK Gonder, PJ Kranzusch, PD Walsh, E Delaporte, E Mpoudi-Ngole, AV Georgiev, MN Muller, GM Shaw, M Peeters, PM Sharp, JC Rayner & BH Hahn (2010), ‘Origin of the human malaria parasite Plasmodium falciparum in gorillas’, Nature 467.

Yotoko KSC & Elisei C (2006), ‘Malaria parasites (Apicomplexa, Haematozoea) and their relationships with their hosts: is there an evolutionary cost for the specialization?’, Journal of Zoological Systematics and Evolutionary Research 44 (4): 265–73

Diet Therapy for Malaria?

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QUESTION:

Is there any tested and proven diet therapy for acute malaria? What food nutrients are essential for prevention of malaria?  And what are their food sources?

ANSWER:

Thanks for your question, Ekuma. I am not aware of any proven and scientifically tested diet therapy for acute malaria, apart from that which is recommended for all severe fevers, which is to hydrate regularly and thus increase intake of water and diluted juices. Some doctors advise to steer clear of solid food during the worst of the fever, but I am not sure whether this is actually to speed recovery or just because patients tend to lose their appetite during this phase anyway.

In terms of nutritional prevention of malaria, again I don’t think there are any dietary supplements as such which have been proven to prevent all malarial episodes. However, quinine is a natural chemical which has anti-malarial properties and so including quinine-rich foods in one’s diet may in this way reduce incidence of malaria. Tonic water is a good example of an everyday foodstuff which contains quinine; the soda known as “bitter lemon”  likewise contains quinine, which is partially why both were popular with colonial expatriates living in malarial countries over the last hundred-odd years.

Finally, there are reports that grapefruit contains a quinine-like substance, and so might help prevent malaria or indeed increase recovery from malarial episodes, but I am not sure if this has been scientifically established as fact. There are a number of other plants, herbs and fruits which advocates of traditional, home remedies suggest may help prevent or treat malaria, but I can’t find ANY solid scientific basis for these claims, nor any reports of trials where these remedies have been shown to be effective.

Overall, the best thing to do if you think you have malaria is to get diagnosed (either at the doctor, a hospital or using a self-diagnosis kit) and then seek medical treatment. Local clinics will be able to tell you what kind of malaria you have, and therefore what treatment is recommended.

For prevention while in malarial areas, sleep under an insecticide treated bednet and try not to get bitten by mosquitoes. If you’re a visitor to a malarial zone, look into getting prophylaxis (preventative medicine) before you travel, and make sure the type of medication you are prescribed is appropriate to the types of malaria found in the regions to which you are going.

In terms of what malaria parasites themselves eat, they infect red blood cells in the human body and use the cells’ own hemoglobin (the protein we need to carry oxygen around our bodies) for energy. This why one of the reasons why malaria sufferers can become anemic; as such, it is important to maintain iron levels after a malarial attack, to prevent any further side effects of the infection.

 

What will happen if malaria is not controlled?

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QUESTION:

In the future, if malaria is not controlled, what will happen?

ANSWER:

This is actually a really important question. Malaria already kills more than one million people each year, with probably around 3.3 billion people at risk from infection. This number will just increase as the world’s population grows, unless successful control measures are implemented.

Moreover, climate change will likely change the areas which are affected by malaria. Certainly, as temperate areas, such as the Mediterranean and the southern USA, get warmer due to climate change, there will be more risk of greater malaria transmission in these regions. Similarly, high altitude areas in tropical regions, which currently have low or no malaria transmission, may find that transmission of malaria becomes possible and even frequent. This may be the case for some of Africa’s major cities, such as Nairobi and Johannesburg, which are currently at a high enough altitude to limit high malaria transmission, but may be negatively affected by climate change with respect to malaria.

Similarly, there are some regions in the world which are currently too dry during parts of the year to allow the larvae of malaria mosquitoes to develop; this results in only seasonal transmission of malaria, after the rains. If climate change affects the patterns or the amount of rain that falls in these areas, transmission risk of malaria will also change, and perhaps in unpredictable ways.

On the other hand, there may be some areas which become more dry with the onset of climate change. These areas may see reduced malaria transmission, but increases in other problems, such as lack of water to grow crops and therefore higher levels of food insecurity and malnutrition.

Therefore, overall it is expected that without control measures, the number of cases of malaria worldwide will continue to increase. As such, it is crucial that we all work together to implement successful measures for prevention, diagnosis and treatment of malaria, and especially in the countries, such as in sub-Saharan Africa, where the burden of the disease is the greatest.

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 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.

In humans, malaria causes severe illness and sometimes death – the World Health Organisation estimates that there are somewhere between 300 and 500 million cases of malaria each year, and as many as 1 million deaths.

Due to the temperature requirements of the parasite’s life cycle, malaria transmission is constrained to tropical and sub-tropical regions around the world, which means that the highest burden of disease falls on some of the world’s poorest people.

Having said that, many cases of malaria can be prevented using simple measures such as sleeping under an insecticide-treated bednet, and especially if promptly diagnosed, most cases can be treated using safe and effective medication. As such, malaria control is a key aim of many international development agencies and also the focus of a many scientific research groups around the world.

For more information about the specifics of malaria, please visit the Malaria Overview section of Malaria.com, or see our news and blogs sections of the website.

What age can be affected by malaria?

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QUESTION:

A child of what age can be affected from cerebral malaria or malaria?

ANSWER:

People of all ages can be affected by malaria, which is what makes it such a public health burden in so many places.

Severe symptoms of the disease, such as the manifestation of cerebral malaria that you mention, can also be seen in children of all ages as well as adults. However, generally, younger children tend to have more serious attacks of malaria, and the disease is most deadly in children under the age of 5, who have not had a chance to build up natural, protective immunity to malaria. This lack of immunity is why malaria is also particularly severe in travellers, who have not been exposed during their childhood. Similarly, changes in the body’s immune response and blood chemistry during pregnancy make pregnant women, no matter what their age, very vulnerable to malaria infection.

Where does malaria appear?

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QUESTION:

Where does malaria first appears on the body?

ANSWER:

That’s a very interesting question! You could say that malaria first appears in the blood, since that is how the parasite enters the human body—it passes into our bloodstream when an infected mosquito penetrates the skin to feed on blood.

The life cycle below, courtesy of CDC, explains more about the next stages of infection, and where the malaria parasite also passes within the human body.

The initial migration of malaria parasites is usually into the liver, after which they reproduce and begin to infect red blood cells. It is the cycles of infecting and bursting out of red blood cells, as part of the life cycle, that usually results in the classic cycles of chills, fever and sweating that characterises malaria infection. So in this way, you could say that malaria is first noticed once it begins to infect blood cells, throughout the body.

malaria_lifecycle_CDC

A generalised life cycle of the malaria parasite (courtesy of CDC; www.cdc.gov)