Primaquine for Malaria Treatment

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QUESTION:

In India what is the duration of primaquine therapy in confirmed Malaria infection?

ANSWER:

Primaquine is usually used to kill the hypnozoite stages of Plasmodium vivax or P. ovale. This life stage of the malaria parasite can reside, dormant in the liver’s hepatocyte cells, even after the patient has completed the normal course of treatment for the infection; at this stage, the patient might not have visible malaria parasites in the bloodstream, and thus be considered “cured”. Despite this, the patient is actually potentially at risk from recurrence of malaria if the dormant liver hepatocytes re-enter the blood stream.

For this reason, patients with P. vivax or P. ovale should complete a course of primaquine in addition to the standard malaria treatment offered. The usual adult dosage for primaquine is 15-30mg base, taken orally, once a day for 14 days.

Do I have malaria?

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QUESTION:

Hi, I went to Ivory Coast August/2003 back March/2004, took some pills to help prevent Malaria on my trip but ran out and did not get more. While I was there I got many mosquito bites.

Around October/03 became very sick, got tested for malaria at the hospital in Quebec but negative. Now May/2011 still have all the same symptoms, flu like symptoms, feeling cold most of the time, chills headaches, tired.

Is there any way I got it? I’ve gone to doctors and doctors and no one can seem to find what is causing this? I am tired of taking tylenols all the time for the body ache. My wife is from there and she’s so sure that I got it from seeing how I am since she’s been around it all her life. Can you help me?

ANSWER:

There are definitely types of malaria that can cause relapses of symptoms many months or even years after an initial infection. These types are not common in the Ivory Coast but if you had many mosquito bites then it is certainly possible that you were exposed. What kind of test did you have for malaria when you returned to Canada?

Often, the test is by looking at a microscope slide of your blood under the microscope—the problem with this test is that it is not very sensitive for low levels of malaria, for example, after the worst of infection, and especially with the types of malaria that cause relapse (these types, P. ovale and P. malariae being the ones you might expect from Ivory Coast, tend to cause less severe illness than the more common type of malaria in Africa, called P. falciparum, doesn’t relapse in the same way, but results in much higher levels of the malaria parasite in the blood, which makes it easier to diagnose on blood slides). Also, since malaria is relatively rare in northern countries like Canada, laboratory technicians are not as experienced at diagnosing the parasite as they are in countries where malaria is endemic.

Having said that, there are of course lots of other illnesses which also cause symptoms similar to that of malaria – fevers, chills, etc. What I would recommend is that you re-visit the doctor, and ask for a more sophisticated test for malaria. Mention that you have had a relapse of symptoms—this should prompt them to use more sensitive tests, such as PCR or a rapid diagnostic test, and to look specifically for P. ovale or P. malariae. Not only will this answer your question about whether you have malaria, but it will allow the doctors to give you the appropriate treatment for your current symptoms (probably chloroquine) as well as treatment to prevent any further relapses (primequine).

Hope this helps!

Causes of malaria

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QUESTION:

What are the causes of malaria?

ANSWER:

Malaria is caused by parasites of the genus Plasmodium. These are single-celled animals known as protozoans (from the Greek ‘protos’ and ‘zoia’ which together mean ‘first animal’) and they are transmitted via mosquitoes that feed on blood; the parasites need both mosquito and human hosts to complete their life cycle (see below a graphic of the complete life cycle, courtesy of CDC). In the process of reproducing, the malaria parasites destroy human red blood cells, which is what causes the clinical symptoms of disease that the patient experiences, such as fever, headaches and nausea.

Malaria life cycle CDC

Generalized malaria life cycle (courtesy of CDC: www.cdc.gov)

There are four main species of Plasmodium that infect humans: P. falciparum, P. vivax, P. malariae and P. ovale. P. falciparum causes the most severe manifestations of the disease and is responsible for the majority of human deaths from malaria. There is a fifth type of malaria, P. knowlesi, which usually infects macaque monkeys but has been known to pass into humans as well.

For more on this, please see Christina Faust’s excellent blog post about her research.

What are the strains of malaria?

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QUESTION:

What are the different strains of malaria?

ANSWER:

Malaria is caused by small, single-celled parasites called protozoans, and specifically ones of the genus Plasmodium. There are many, many species of Plasmodium, which infect a wide variety of different species, from lizards and birds to rodents, bats and primates. Of all the species of malaria, four main ones infect humans – these are P. falciparum, P. vivax, P. ovale and P. malariae. A fifth species, P. knowlesi, usually infects macaque monkeys in South East Asia but has been known to cross over to humans. Each of these species causes slightly different manifestations of the disease in humans, and even within the species, there are regional strains and variations. Probably the most distinct internal division within a malaria species is within P. ovale, where two sub-species are currently recognised: P. ovale curtisi and P. ovale wallikeri. These two forms are identical morphologically (that is, in the way they look under the microscope) but can be differentiated genetically.

Can malaria come back?

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QUESTION:

If you had malaria once, can it return for a second time without being in a malaria area?

ANSWER:

Yes. There are several ways in which malaria can come back without being re-infected again. The blood forms of the parasites can sometimes persist at low numbers, so that the patient no longer has any symptoms; if these blood forms begin to reproduce again, the patient will once again begin to feel sick and have malaria symptoms. This is known as ‘recrudescence’ and can occur as quickly as within the same year as the initial infection but also as long as fifty years later, depending on the type of malaria! Treating the infection thoroughly, and being tested for parasites after treatment, is one way to avoid recrudescence.

The other way in which malaria can come back is through ‘recurrence’, which is when the malaria parasite enters a dormant phase which resides in the liver. Again, the patient will feel no symptoms while the malaria is dormant, but once these liver stages change into the blood stages and reproduce, symptoms will reoccur. This form of relapse only occurs with Plasmodium vivax and P. ovale infections, and can be prevented through taking an additional form of medication, called primequine, at the same time as the normal malaria drugs when diagnosed. This extra medicine kills the liver forms of malaria and thus prevents recurrence. For more details on this, please see the comments I made, on behalf of Dr Etty Villanueva, on the post ‘Malaria Symptoms and Causes’, published on the 22nd of February, 2011.

Treatment for Malaria

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QUESTION:

How do you treat malaria?

ANSWER:

Malaria can be treated with a number of different types of medication; which one to use depends on the type of malaria you have, as well as whether resistant strains are known to occur in your area. Below I have copied the response I wrote to a similar question on malaria treatment, posted on the 2nd of May, 2011:

In most cases of non-Plasmodium falciparum malaria (the most deadly form of malaria, found throughout the world but most prevalent in sub-Saharan Africa), and even in some places where P. falciparum has not yet developed resistance, treatment with chloroquine is sufficient.

The dosage will depend on body weight (usually approximated by age). Where there is a risk of chloroquine-resistant malaria occurring, treatment of non-complicated cases will usually consist of orally-administered artemisinin-based combination therapy (or ACT) – again, the dosage will depend on age/weight.

For severe malaria, parenteral ingestion of drugs is required. For the treatment of cerebral malaria, caused by P. falciparum, quinine is the traditional drug of choice, though artemisinin has also been shown to be effective. Anti-convulsants and anti-pyretics (to reduce fever) should also be administered.

In cases of infection with P. vivax or P. ovale, the parasite can become dormant in the liver and result in a relapse of the disease if not treated properly. As such, patients with either of these forms of malaria should also be treated with primaquine.

If you have, or suspect you have a health problem, you should visit a physician for a medical diagnosis and treatment.

Started Late on Anti-malaria Medication

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QUESTION:

I’m in a malarious country and I had no idea about anti-malarials until I got here, so I started taking anti-malaria(doxycicline) two weeks late. It has been three weeks since I started taking the medicine. Do you think it would work or should I stop taking it?

ANSWER:

It depends a bit on where you are, and what types of malaria are in your region. Plasmodium falciparum usually takes between 7 and 14 days for symptoms to develop after exposure; P. vivax and P. ovale take between 9 and 14 days. P. malariae, on the other hand, sometimes doesn’t show symptoms until 30 days after infection. However, the most acute and dangerous form of malaria is that caused by P. falciparum; as such, if you haven’t had any symptoms since you started taking anti-malarials three weeks ago, you should be ok, and it certainly would be advisable that you continue with the preventative medicine while you remain in the malarial area.

It’s also worth mentioning that because of the lag between infection and symptoms, in many cases you need to continue taking antimalarials for some period of time after you leave the malaria zone. Of course, if at any point you start to develop symptoms, such as fever or chills, go to a hospital or see a doctor for prompt diagnosis.

Treatment for malaria in Africa

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QUESTION:

What is the treatment for malaria in Africa?

ANSWER:

The appropriate form of treatment for malaria, regardless of where you are, depends on the type of malaria you have. This can be determined through diagnosis; each of the main malaria parasites that ordinarily infect humans (P. falciparum, P. vivax, P. malariae and P. ovale) looks slightly different under the microscope, although you have to be well trained to tell them apart! Rapid diagnostic tests (RDTs) can also sometimes distinguish between malaria species, although many RDTs only test for P. falciparum, he most acute, severe and deadly of the species.

In much of Africa, P. falciparum is the most common and dangerous form of the disease. In some places, it can be treated with chloroquine, though in many places the parasite has developed resistance to this drug, so other treatment is necessary.

The most common drugs given in areas with known chloroquine-resistant strains of P. falciparum are ACTs (artemisinin-based combined therapies). There are some parts of Africa where other forms of malaria, such as P. ovale and P. vivax, can also occur – it is important to know whether a patient is infected with these species as they require an additional form of treatment, the drug primequine, in order to kill dormant liver stages that characterise these species and can lead to a relapse of infection months or even years after the initial exposure.

What is malaria? What Causes Malaria?

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QUESTIONS:

What is malaria?
What causes malaria?

ANSWER:

I have copied below the text from an earlier question, also asking about the causes of malaria and explaining what it is:

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.


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.