Malaria Relapse

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QUESTION

Why do I suffer from constant malaria attack? The doctor has prescribed different prescriptions every time I get an attack but its still coming back. What could be the problem?

ANSWER

There are a number of possible answers to your question. First of all, your doctor might not be prescribing the right type of treatment for the type of malaria that you have. The World Health Organisation now recommends that all uncomplicated cases of malaria should be treated with artemisinin-based combination therapies (ACTs), such a Coartem. However, in some places, doctors still prescribe other drugs, such as Fansidar or chloroquine. This can be a problem, as in many areas, the local kinds of malaria have become resistant to these earlier drugs, and so you may not be cleared of the infection. This is called recrudescence—when a malaria infection is not cleared completely from the blood and so symptoms come back once the treatment has stopped.

Alternatively, if there is a longer time interval between your episodes of illness, you may be suffering from relapses. This occurs with two particular types of malaria: Plasmodium vivax and P. ovale. These types of malaria can form liver stages which remain dormant even after the treatment you take kills all the malaria in your blood. Therefore it will appear like you have been cured, but really you still have an infection in the liver.

These liver stages can re-activate and re-enter the blood, causing another episode of malaria symptoms months or even years after the initial infection. If your doctor finds that you are positive for one of these two types of malaria, you should talk to him/her about the possibility of taking primaquine. This drug kills the liver stages of the parasite, but is not appropriate for people with G6DP deficiency, so you should be tested for that first.

Finally, there is the possibility that you are continually being re-infected with malaria. In this case, you should take more preventative precautions. For example, sleep under a long-lasting insecticide-treated bednet, wear long-sleeved clothing (especially at night) and cover exposed skin with insect repellent. All of these measures will help prevent mosquito bites, which transmit malaria. In addition, you could consider indoor residual spraying, which coats the walls inside your house with insecticide to further eliminate the presence of mosquitoes.

When to Seek Malaria Treatment

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QUESTION

I have been in New Guinea recently and 2 weeks on am exhibiting all the signs and symptoms of malaria. What is best course of action, considering I do not know what sort of mosquito was hovering about?

ANSWER

You should visit your physician or a clinic immediately. Depending on where you are, you may have to visit a specialist travel medicine clinic, to be sure that you will be seen by someone who understands how best to diagnose malaria. They should take blood and examine it under a microscope (using thick and thin blood films), or they may utilise a rapid diagnostic test. Either way, they will be able to determine whether you have malaria and if so, which type of malaria you have. 

This is important because some types of malaria, such as Plasmodium vivax (which is very common in PNG) can remain dormant in the liver after the initial infection has been treated, which leads to relapses months or years later. In order to prevent relapses, if you find you are infected with P. vivax you should inquire about the possibility of also being given primaquine, which is a drug that can kill these liver stages.

Symptoms and Causes of Malaria

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QUESTION

What are the symptoms and causes of malaria?

ANSWER

Malaria is caused by a parasite called Plasmodium, which is transmitted via the bites of infected mosquitoes. In the human body, the parasites multiply in the liver, and then infect red blood cells. Usually, people get malaria by being bitten by an infective female Anopheles mosquito. Only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken on an infected person. When a mosquito bites an infected person, a small amount of blood is taken in which contains microscopic malaria parasites. About 1 week later, when the mosquito takes its next blood meal, these parasites mix with the mosquito’s saliva and are injected into the person being bitten.

Because the malaria parasite is found in red blood cells of an infected person, malaria can also be transmitted through blood transfusion, organ transplant, or the shared use of needles or syringes contaminated with blood. Malaria may also be transmitted from a mother to her unborn infant before or during delivery (“congenital” malaria).

There are five kinds of malaria known to infect humans: Plasmodium falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi. The symptoms of malaria differ depending on the type of malaria; P. falciparum  is the most deadly and severe form of the disease. General symptoms of malaria include  include fever and flu-like illness, including shaking chills, headache, muscle aches, and tiredness. Nausea, vomiting, and diarrhea may also occur. Malaria may cause anemia and jaundice (yellow coloring of the skin and eyes) because of the loss of red blood cells.

Symptoms usually appear between 10 and 15 days after the mosquito bite. If not treated, malaria can quickly become life-threatening by disrupting the blood supply to vital organs.

What are the causes of malaria?

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QUESTION

What are the causes of malaria?

ANSWER

Malaria is caused by a parasite called Plasmodium, which is transmitted via the bites of infected mosquitoes. In the human body, the parasites multiply in the liver, and then infect red blood cells. Usually, people get malaria by being bitten by an infective female Anopheles mosquito. Only Anopheles mosquitoes can transmit malaria and they must have been infected through a previous blood meal taken on an infected person. When a mosquito bites an infected person, a small amount of blood is taken in which contains microscopic malaria parasites. About 1 week later, when the mosquito takes its next blood meal, these parasites mix with the mosquito’s saliva and are injected into the person being bitten.

Because the malaria parasite is found in red blood cells of an infected person, malaria can also be transmitted through blood transfusion, organ transplant, or the shared use of needles or syringes contaminated with blood. Malaria may also be transmitted from a mother to her unborn infant before or during delivery (“congenital” malaria).

There are five kinds of malaria known to infect humans: Plasmodium falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi.

Is malaria possible years after bite?

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QUESTION

My child had a fever for 40 days after returning from a cruise 3 years ago. I begged the pediatrician to test for malaria because she got bit by something in Mexico but they laughed at me. She has had swollen lymph nodes on both sides of her neck for 3 years and all the docs tell me you can have swollen lymph nodes forever but now she has them in her groin and under arm on left side. She is pale and tired all the time. I took her back to the pediatrician and her cbc was normal so the dr is blowing it off. Malaria and Lymphoma are on my mind. My question is, Can malaria live in the body that long without it killing you?

ANSWER

Malaria can certainly survive in the body for a long time, but usually would present as recurring episodes of fever rather than enlarged lymph nodes (the malaria parasites reside dormant in the liver). There are two types of malaria that can reside in the body for extended periods: Plasmodium vivax and P. ovale. The former is found in parts Mexico, but cases of malaria are rare, especially in coastal areas. Unfortunately, malaria can only be detected when it enters the blood again – this occurs during the fever episodes. So, if your daughter does have a fever again, it might be worth asking for a malaria test, and specifically to look for P. vivax. If positive, there is a drug, primaquine, which can be taken to kill the remaining liver stages of malaria and prevent further relapses. However, overall, your daughter’s case doesn’t sound like malaria. What was your daughter’s Hb level? Anemia could explain the pallor and lethargy, though your pediatrician should have spotted that on the blood tests.

Where did malaria start in Africa?

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QUESTION

Where did malaria start in Africa?

ANSWER

Malaria has been present in Africa for tens of thousands of years; given this ancient history, it is very difficult to know exactly where it first entered the continent. Also, there are several different types of malaria in Africa, which have likely had different histories, and malaria researchers continually unearth new evidence regarding the origins of these different species.

For example, it has long been thought that Plasmodium falciparum, the most deadly form of malaria, emerged somewhere in the western Congo Basin in Central Africa. Originally, it was thought to have crossed over into humans from a closely related species found in chimpanzees, but recent research, published only in 2010, has suggested that a new species, found in gorillas, is actually the closer relative.

Plasmodium vivax, the most geographically widespread species of malaria that infects humans, has less clear origins. Many of its closely related species occur in south-east Asia, which leads some researchers to suggest this is where it emerged, passing into Africa as humans and their livestock moved across Asia towards the Middle East and North Africa, or possibly via  migration through Madagascar. However, other researchers argue that the high prevalence of certain genetic mutations which protect against Plasmodium vivax malaria found in populations in Africa and of African descent, and particularly West Africa, is evidence that P. vivax actually originated on this continent.

How long do I need to carry a Malaria Risk Card

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QUESTION

Hello, 13 months ago I worked in Nigeria, Africa for a period of 6 weeks. During which time I took Malarone tables daily. I think I was only bitten once or twice when there – but have never had Malaria. I currently carry a Malaria Risk Card in my wallet. At the time I was told I could potentially contract Malaria up to a period of 2 years after exposure – is this correct, or can I now remove the Risk Cards from my wallet?

ANSWER

If you never had malaria while you were in Nigeria, then you certainly would not still be at risk from it now. The only case in which you might still be at risk is if you had been diagnosed with either Plasmdodium ovale or P. vivax (two of the five forms of malaria that infect humans) – these can cause relapses months or even years after initial infection.

However, as I said above, since you did not have malaria at all, this does not apply to you. It is true that malaria has a latent phase, and so can sometimes only start to cause symptoms after someone returns home from a malarial area, but this period is usually one or two weeks, and certainly not months or years!

Malaria Relapse

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QUESTION

I had malaria in Papua New Guinea 40 years ago and had many relapses. I had one 11 years ago and was in hospital for 3 weeks. I have been to a massage therapist who used a hand machine giving out pulses rather strong a bit like tiny electric shots could this activate malaria?

ANSWER

The reasons why malaria relapses are not well known. Malaria acquired in different places tends to have different relapse times (faster in the tropics, less frequent in sub-tropical or temperate regions) and there is also some evidence that being bitten again by mosquitoes can trigger relapse. I am not aware of any evidence that electric pulses could trigger relapse, but likewise cannot discount the possibility! On another note, there is medicine that can be taken to prevent further relapse, by killing the dormant liver forms of the malaria parasite. It is called primaquine, and is only effective is taken exactly as prescribed for a 2 week period. Some people with G6DP deficiency may also not be recommended this medicine, so before prescribing it, your doctor should test you for this deficiency.

How many types of malaria are there?

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QUESTION

How many types of malaria are there?

ANSWER

There are four species of malaria parasite that commonly infect humans. These are: Plasmodium falciparum, P. vivax, P. ovale and P. malariae. In addition, a fifth species, P. knowlesi, is starting to draw public health attention as an infection in humans in south-east Asia, and particularly Borneo – previously, it was thought to only infect macaque monkeys.

Apart from these five species, there are many other species of Plasmodium, which infect other primates (including gorillas, chimpanzees and orangutans), rodents, birds and reptiles. A closely related group of parasites, called Hepatocystis, infects monkeys, squirrels, hippopotamus and bats.

Child Has Recurring Malaria

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QUESTION

My two year old daughter was affected by malaria 9 months back we took proper course and also the follow up course of 6 weeks. After 2 months post 6 weeks she was infected again by malaria and now again she is getting fever and fear this could be malaria again.

ANSWER

If you suspect she might have malaria again it is important you go and get her tested immediately, as then the doctor can prescribe appropriate treatment. This is particularly important for young children, as they are most susceptible to severe malaria. You should also try to find out what type of malaria she had/has. Repeated attacks of malaria can occur three ways. The first is re-infection – the first infection was cured by the medication, but then your daughter was exposed to malaria again, through the bite of an infected mosquito. Preventative measures, such as making sure she sleeps under a long-lasting insecticide treated bednet, can help reduce the risk of re-infection. Secondly, it could be what is called “recrudescence” – this is when the treatment brings the number of parasites in the blood below detectable levels, and low enough so that symptoms subside.

However, once the treatment course stops, the parasite is able to replicate in the blood again, and symptoms return. This is rare if the full, proper course of medication is taken – in most circumstances, Coartem (artemether plus lumefantrine) should be the first line of treatment and it is very effective against preventing recrudescence. Finally, there is relapse. This only occurs with two species of malaria: Plasmodium vivax and Plasmodium ovale. In this case, the parasite is cleared from the blood by the treatment, but some parasites escape by laying dormant in the liver. These can then reactivate weeks, months or even years after the initial infection. Normal malaria medication can be given to treat relapses of infection, but an additional drug, called primaquine, should also be given, to kill the remaining dormant liver stages. Your doctor should be able to tell you whether he would recommend this drug for your child – they should also be tested for G6DP deficiency prior to taking the drug.