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

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)

Malaria Treatment While Pregnant?

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QUESTION:

1) I am two months pregnant. Please, what drug can I use to treat malaria? 2) How often should I treat malaria?

ANSWER:

The specific answer to your question depends a bit on whether you believe you are already actively infected with malaria (in other words, you are feeling ill right now, or have done recently) or if you would like information on preventing malaria during your pregnancy.

In both cases, there are certain drugs which have been tested as safe for pregnant women, but whether these drugs are appropriate for you depends on where you live, what types of malaria you might have been exposed to, and, as I mentioned first, whether you are seeking treatment for an existing episode of malaria or want to prevent future illness.

I have asked one of our board members, who is an expert on maternal health and pregnancy, to comment further, so please check back here soon!

How does malaria infect the body?

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QUESTION:

How does malaria infect the body?

ANSWER:

Malaria is transmitted to humans via certain species of mosquito. The parasite that causes malaria, called Plasmodium (there are several species, which cause slightly different forms of the disease), lives in the saliva of the mosquito and is introduced into the human blood when the mosquito bites through the skin. It is interesting to note that only female mosquitoes transmit malaria; male mosquitoes don’t feed on blood, only on nectar and other plant juices, and their mouth parts are too soft to break human skin!

Once the parasite is in the human bloodstream, it undergoes several different life stages. Throughout, it must evade the human immune system, and it has a number of clever ways to do this. One method is by producing a protein which it attaches to its surface; this acts as a “cloak” against the human immune system and hides the parasite. The parasite also uses other proteins to complete its life cycle, for example several are used to enter red blood cells, where part of the reproductive cycle of the parasite is carried out. Finally, after several transformations and cycles of reproduction, the malaria parasites are released again into the bloodstream, where they can be picked up by another female mosquito, and transported to a different human.

For more information about some of the mechanisms for evading the immune system, check out this article from the BBC website, which summarises some recent findings about Plasmodium falciparum, the malaria parasite which causes some of the most debilitating and deadly malaria cases worldwide.

 

 

Is there malaria in Papua New Guinea?

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QUESTION:

Is Papua New Guinea infected of malaria?

ANSWER:

There is malaria in many parts of Papua New Guinea, and especially in the coastal regions. Chloroquine-resistant malaria has been reported from PNG so if travelling to malarial zones in the country you should ask your doctor about getting a prescription for another form of prophylaxis (preventative drugs), such as Malarone, Lariam or doxycycline. it is also recommended to sleep under an insecticide-treated bednet.

Parts of the country which are above 1800 metres of altitude (5900 ft) are considered free of transmission but you should consult with local doctors before travelling to specific areas to see what they recommend in terms of preventative measures you can take.

How did malaria start?

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QUESTION:

When did malaria happen?

ANSWER:

It is believed that Plasmodium, the parasite which causes malaria in a wide variety of animals, first evolved in reptiles. Even today, reptiles are infected by species of Plasmodium that are related to those that infect humans. The parasite probably then evolved to infect birds, and then, more recently, to infect mammals. Many mammals can be infected with malaria-like parasites, but most commonly rodents (like rats and mice) and primates (including humans).

The exact origins of human malaria are less clear, and indeed, there are several different types of malaria, caused by different Plasmodium species, so it would be expected that there were different evolutionary origins for these different types. The most common and deadly form of human malaria, P. falciparum, was long believed to have crossed over about 500,000 years ago from a closely related chimpanzee malaria species called P. reichnowi, and evolved to infect humans.

However, a recent paper in Nature (Liu et al., “Origin of the human malaria parasite Plasmodium falciparum in gorillas,” in volume 467 and pages 420-425) has used molecular evidence, from almost 3000 samples and several genetic regions, has instead suggested that P. falciparum evolved from a type of malaria which is found in western lowland gorillas. However, the paper did not remark on when this cross-over might have occurred. No doubt more studies will be done on this subject in the near future, which will give us a better idea of when the first cases of truly “human” malaria might have occurred!

Is there Malaria in Naboomspruit, South Africa?

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QUESTION:

Is Naboomspruit in South-Africa a malaria area?

ANSWER:

Naboomspruit (also known as Mookgopong) is located in Limpopo province in South Africa; malaria is endemic in parts of this province, namely the eastern border of South Africa (next to Mozambique and Swaziland), and including popular tourist areas such as Kruger National Park. In these regions, precautions against malaria, such as sleeping under an insecticide-treated bednet and taking preventative (prophylactic) medicine against malaria are highly recommended.

However, regions further away from the border, such as Naboomspruit, are generally considered zones of low to no transmission. However, transmission may still occur at some points in the year (particularly after rains) so some precautions would be advisable, although medication against malaria is probably not necessary. Instead, if visiting, or indeed if living in the area, it would be recommended to avoid getting bitten by mosquitoes by using insect repellant, wearing long-sleeved and dark clothing at dawn and after dusk and if being particularly cautious, by sleeping under an insecticide-treated bednet.

Bear in mind also that these are simply recommendations, and things may change over time and with variations in local climate; it would be worth asking a local doctor or hospital what the immediate risks of malaria are before travelling to a particular location.