How is Malaria Treated

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QUESTION

How is malaria treated?

ANSWER

This answer is copied from an earlier question about the various available cures for malaria.

Malaria can be cured with a number of different medications, depending on then type of malaria and how far the disease has been progressed.

For standard, non-complicated Plasmodium falciparum malaria, the World Health Organisation recommends use of artemisinin-based combination therapies (ACTs), such as Coartem. This is due to increasing levels of resistance to chloroquine in many parts of the world. Indeed, even though chloroquine is still used in many places as first-line treatment against P. vivax, P. malariae, P. ovale and P. knowlesi uncomplicated malaria, there is some evidence that resistance to this treatment is also emerging, for example in P. vivax in parts of south-east Asia.

In cases where malaria infection has progressed to a stage where oral administration of medication is not possible, or where cerebral symptoms are suspected, the usual treatment option is intravenous quinine.

In addition, P. vivax and P. ovale malaria parasites are able to produce forms (called hypnozoites) which can become dormant in liver hepatocyte cells after the blood stages of the infection have been cleared. These dormant forms can become reactivated weeks or even months or years after the initial infection, which is called a “relapse” of the infection. One drug, called primaquine, is able to kill these liver stages, and so patients with either of these types of malaria should also discuss the possibility of taking primaquine.

Apart from these first-line treatments, there are other medications which are used against malaria, both prophylactically as well as for treatment. These include orally-administered quinine, pyrimethamine, mefloquine, proguanil, atovaquone and sulfonamides.

 

Passing Malaria to Baby

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QUESTION

I contracted Malaria 3.5 years ago (either in Uganda or Rwanda). I believe it was the Plasmodium falciparum strain. Upon my diagnosis, I was treated and have been healthy since.

In regards to pregnancy, is it safe for me to have a baby? What are the chances of passing the malaria virus to the baby?

ANSWER

First of all, malaria is caused by a single-celled parasite, not a virus.  Secondly, you probably don’t have to worry—malaria is only very rarely transmitted directly between a mother and her unborn baby, via infected red blood cells passing through the placenta. When I say rare, I mean very rare, especially in developed countries without endemic transmission. There are only 48 cases of this occurring in the United States in the last 60 years, for example. Moreover, this can only occur if you actually have malaria during the pregnancy; if you were successfully treated when you had malaria 3.5 years ago, the parasite should no longer be present at all in your body.

P. falciparum does not lay dormant in the body, unlike some other types of malaria. The only thing to consider is if you plan to travel to malarial areas while you are pregnant – pregnancy makes women more vulnerable to malaria infection, and many forms of malaria preventative medication and treatment have not been thoroughly tested for safety in pregnant women. If you are planning on travelling to malarial areas while pregnant, it would be wise to consult with a specialist travel doctor for the most up-to-date recommendations of malaria prevention when pregnant.

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.

How does oxygenated blood reach the brain?

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QUESTION

How does the oxygenated blood actually reach the brain???

ANSWER

Two main artery pairs supply the brain with oxygenated blood from the lungs. These are the internal carotid arteries and the vertebral arteries.

One of the major risks of infection with Plasmodium falciparum malaria is that the parasite induces red blood cells to sequester to the sides of small blood vessels in major organs, rather than stay in the peripheral blood system in the limbs. If this happens in the brain, the resultant loss of oxygen supply and other complications leads to cerebral malaria, which is a serious condition and can lead to convulsions, permanent neurological damage and even coma and death. As such, it is crucial to treat all cases of malaria swiftly and effectively, but none so urgently as P. falciparum infections.

Symptoms of Malaria

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QUESTION

What are the main symptoms of malaria?

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.

Is it just a cold?

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QUESTION

I came back from a Kenya safari and Mombasa beach holiday 21 days ago.
I took my malaria tablets as prescribed, and only got 5 bites on my last morning.

Since yesterday, I have been feeling hot then cold, though not shivering or overly sweating. A headache which is constantly there. I have also today been sick after eating/drinking. Feeling really tired. Also sore throat and blocked nose which makes me think its more a cold, so don’t want to bother my GP.
Any advice would be appreciated.

ANSWER

Malaria does have an incubation period, which means that the symptoms only show up days or weeks (or in some cases, years) after the patient is bitten by an infected mosquito. Different species of malaria have different incubation times; Plasmodium falciparum, which is the most common form in sub-Saharan Africa, usually has shorter incubation times than P. vivax, a still-acute but less deadly form. P. falciparum incubation is usually between 1 and 3 weeks, although taking anti-malarial medication can extend it. As such, since you began experiencing symptoms within a few weeks of returning, there is definitely a chance it could be malaria, although less likely if you haven’t experienced any fever (this is a key symptom of malaria, and usually goes in cycles of about 48 hours). However, since malaria is a serious issue, and can progress rapidly if not treated, I would suggest you see your GP – if you tell them that you have recently returned from a highly malarial area, they will understand your concern! Alternatively, if you live near London, if you have a fever you can go straight to the A&E department of the Hospital for Tropical Diseases (HTD) in Warren Street, where they have doctors that specialise in traveller’s health and tropical medicine.

How was Plasmodium Falciparum AMA1 Discovered?

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QUESTION:

Plasmodium falciparum AMA1 was discovered how?

ANSWER:

AMA1 stands for “apical membrane antigen 1”, and it is a protein expressed in the cell membrane of the P. falciparum parasites.

Whereas many of these antigenic proteins are highly variable between parasites, this one appears to be relatively well conserved in evolutionary terms, and therefore is a leading drug target candidate for development of new therapeutic medication against malaria.

The presence of AMA1 was elucidated during the genome sequencing of Plasmodium falciparum, which was completed in 2002; in the same year, mass spectrometry of the proteins present in P. falciparum was also done, shedding light on the exact structure and biochemistry of AMA1. Both of these studies were published in Nature magazine in 2002.

Chloroquine Resistant Malaria

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QUESTION

What is chloroquine resistant malaria?

ANSWER

Chloroquine-resistant malaria is exactly what it sounds like—particular types of malaria which are not cured by treatment with chloroquine.

Chloroquine was first discovered in the 1930s in Germany and began to be widely used as an anti-malaria post-World War II, in the late 1940s. However, resistance to the drug also rapidly emerged, with the first cases of Plasmodium falciparum not being cured by administration of chloroquine being reported in the 1950s.

Since then, resistance has spread rapidly (since obviously it is beneficial to the parasite to be resistant, so various mutations conferring this protection have arisen multiple times in different areas in the world and also been passed on preferentially to new generations of malaria parasites), and now chloroquine resistant P. falciparum can be found globally in malaria-endemic areas.

Chloroquine resistance in Plasmodium vivax has also now arisen, though more recently—the first reports came from 1989, in Australia, in travellers returning from Papua New Guinea. Now, chloroquine resistant forms of P. vivax are found in multiple locations in south-east Asia, such as Myanmar and India, as well as from Guyana in South America.

Nowadays, other drugs, and notably ones containing artemisinin-based compounds, are preferentially used to treat uncomplicated malaria and especially in areas where chloroquine resistance is known to occur. However, due to fears of resistance to these compounds also developing, the World Health Organisation recommends that artemisinin-based compounds only be administered in conjunction with other anti-malaria drugs, such as lumefantrine (which in combination with artemether forms the widely-used anti-malarial treatment Coartem). These combinations are known as artemisinin-based combination therapies, or ACTs for short.

Examination of Malaria Parasite

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QUESTION

How can you examine malaria parasites?

ANSWER

Malaria parasites are usually examined under a microscope using a peripheral blood smear method (also called a blood film). Thick blood smears, which use a large unsmeared drop of blood, are sensitive since a large number of red blood cells can be examined, though the parasites, if present, are difficult to distinguish morphologically.

For species-level identification of malaria parasites, a thin blood film is more commonly used, whereby a small volume of blood is smeared thinly across the slide and then stained, usually with Romanowsky stain, in order to see the detailed structures which differentiate the different species of malaria. It is crucial to make the blood films soon after the blood sample has been taken, and to store the blood in an appropriate anti-coagulate.

Characters to look out for include the presence of Maurer’s dots on the surface of red blood cells infected with Plasmodium falciparum. You may also see multi-infected red blood cells with this species, and it is rare to see mature trophozoites or schizonts with this parasite since when this stage is reached the red blood cells are usually sequestered deep within major organs and so are not readily present in the peripheral blood.

These parasites have crescent-shaped gametocytes. Plasmodium vivax, on the other hand, enlarges red blood cells that it infects and seems to show a preference for immature red blood cells. The presence of Schüffner’s dots is also characteristic – these looks like specks or granules on the cell surface of the infected red blood cell. P. ovale is very similar to P. vivax, in that it also enlarges the red blood cells and can have Schüffner’s dots, but fewer merozoites tend to be present per cell and infected red blood cells tend to look elongated. P. malariae does not alter the size or shape of the red blood cell it infects and tends to form rosette-like patterns of 8-10 merozoites. Later on in maturation, its trophozoites may form characteristic band-like patterns across the cell.

Anti-Malarial Tablets for Kenya

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QUESTION

Which are the best tablets to take against malaria in Kenya?
Is there a malaria vaccination?

ANSWER

I’ll answer your second question first—no, there does not yet exist a commercially available malaria vaccine. Currently, one promising vaccine candidate is undergoing Phase 3 clinical trials in children in sub-Saharan Africa; recently published preliminary findings suggest that it provides roughly 50% protection against malaria.

As for which tablets you should take, there are a number of options, and choosing between them is basically a matter of personal preference. The three main kinds recommended for sub-Saharan Africa are doxycycline, atovaquone/proguanil combination (sold under the brand name Malarone) and mefloquine (sold as Lariam). These three differ in how you take them (usually once a day for doxycycline and Malarone and once a week for Lariam), how expensive they are (doxycycline is the cheapest, Malarone the most expensive) and the side effects you might experience (sun sensitivity is a big problem for some people on doxycycline, some people report hallucinations on Lariam, whereas Malarone usually has the fewest severe side effects).

If you’re not sure what’s best for you, you can always talk it over with your doctor when asking for the prescription, and they might have recommendations, based on their knowledge of your health and specific requirements.

It is worth noting that levels of chloroquine resistance are very high in sub-Saharan Africa, and so chloroquine is not recommended as a prophylactic when travelling to this region.