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.

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.

Treatment for Malaria

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QUESTION:

What is the main medicine to cure malaria and about safety precautions?

ANSWER:

There are a number of medicines used to treat malaria. Traditionally, chloroquine has been the first line drug of choice for uncomplicated, non-resistant malaria. However, several types of malaria, and most notably Plasmodium falciparum, the most severe and deadly kind, has become resistant to chloroquine in many places. In some parts of south-east Asia, Plasmodium vivax has also begun to show worrying signs of chloroquine resistance. In such settings, where resistance to chloroquine is suspected, the first line medications for uncomplicated cases are artemisinin-based combination therapies (ACTs), such as Coartem.

The World Health Organization has recommended that artemisinin only be given in combination with another drug to prevent malaria also becoming resistant to this therapy as well. Cases of malaria which have progressed beyond the grasp of that treatable with oral medication as described above (so-called “complicated” cases, most common with P. falciparum infection) are usually given intravenous quinine as a first-line response.

All of these treatments have been rigorously tested in strictly controlled clinical and field trials, and while they may have side effects, they are generally mild and in most cases, the patient will be given the dose without prior testing for reaction to the drug. One exception is with primaquine, which is sometimes used as a preventative medication against malaria and can also be used to treat the liver stages of P. vivax and P. ovale. Primaquine is known to cause severe haemolysis in people with G6DP deficiency, and so people with a high statistical probability of having this condition (for example due to family history or ethnicity) should be tested prior to being given primaquine.

Drugs for Malaria

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QUESTION

What drugs are used in the treatment of malaria?

ANSWER

There are a number of medicines used to treat malaria. Traditionally, chloroquine has been the first line drug of choice for uncomplicated, non-resistant malaria. However, several types of malaria, and most notably Plasmodium falciparum, the most severe and deadly kind, has become resistant to chloroquine in many places. In some parts of south-east Asia, Plasmodium vivax has also begun to show worrying signs of chloroquine resistance. In such settings, where resistance to chloroquine is suspected, the first line medications for uncomplicated cases are artemisinin-based combination therapies (ACTs), such as Coartem.

The World Health Organization has recommended that artemisinin only be given in combination with another drug to prevent malaria also becoming resistant to this therapy as well. Cases of malaria which have progressed beyond the grasp of that treatable with oral medication as described above (so-called “complicated” cases, most common with P. falciparum infection) are usually given intravenous quinine as a first-line response.

All of these treatments have been rigorously tested in strictly controlled clinical and field trials, and while they may have side effects, they are generally mild and in most cases, the patient will be given the dose without prior testing for reaction to the drug. One exception is with primaquine, which is sometimes used as a preventative medication against malaria and can also be used to treat the liver stages of P. vivax and P. ovale. Primaquine is known to cause severe haemolysis in people with G6DP deficiency, and so people with a high statistical probability of having this condition (for example due to family history or ethnicity) should be tested prior to being given primaquine.

 

Drugs to Treat Pregnant Woman with Malaria

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QUESTION:

What are the drugs for a pregnant woman who has malaria for the first to third trimester?

ANSWER:

The treatment of malaria in pregnant women has become more challenging in recent years, as many types of malaria are developing resistance to the standard arsenal of drugs. In locations where the dominant form of malaria is still chloroquine-sensitive, chloroquine can be used safely throughout pregnancy.

However, given the high levels of chloroquine-resistance, other drug regimens may be required. Currently, first-line treatment options for uncomplicated malaria caused by Plasmodium falciparum (many strains of which are resistant to chloroquine), is quinine plus clindamycin (doxycycline is contraindicated in pregnant women). In the second and third trimesters, artesunate plus clindamycin can be administered, or the artemisinin-based combination therapy (ACT) commonly used in that region, although some of these combinations, particularly those containing artemether, have limited safety testing in pregnant women. In general, the paucity of controlled, randomized trials has posed a problem to creating safe and effective recommendations for the treatment of malaria in pregnant women.

Malaria Re-occurrence

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QUESTION:

I’ve been infected with malaria vivax, for this i’ve taken the treatment for three days, after three days i don’t have any symptoms but after two days again I’m feeling the fever and abdominal pain which i’m having since the diagnosis is still persisting. Why is it happening? Are there any chances even after treatment for re-occurrence? My urine is yellow color but there is no jaundice?

ANSWER:

“Vivax” malaria, caused by the parasite Plasmodium vivax, is known for cyclical fevers every couple of days. As such, it may be that while the medication is working, you are still experiencing some mild symptoms as the infection is not completely cleared. For this reason, it is very important to take the full course of medication prescribed to you by your doctor; DO NOT stop taking it as soon as you feel better, as you might not have killed all of the malaria parasites in your blood, putting yourself at risk for the infection to persist. Alternatively, it might be that the strain of P. vivax you have is not responding to the medication you have been given; in parts of Papua New Guinea and Indonesia, for example, the local strains of P. vivax have been shown to have high levels of chloroquine resistance, which is usually used for treating P. vivax. If you are located in an area of known P. vivax resistance to chloroquine, your doctor should be able to recommend a different regimen of treatment to ensure that the infection is cured thoroughly. You should take a blood test after completing treatment to be sure that the parasite is no longer in your blood stream. In addition, P. vivax can produce dormant liver stages called hypnozoites that can remain within the liver hepatocyte cells and cause relapse or recurrence of the disease many weeks or months after the initial infection. To destroy these liver stages, and thus prevent relapse, you should ask your doctor about taking another drug once you have completed your initial treatment. This second drug is called primaquine, and will kill the P. vivax hepatocytes.

Malaria Treatment

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QUESTION:

What is the proper treatment for people with malaria symptoms?

ANSWER:

The proper treatment for malaria depends on the type of malaria parasite that the patient is infected with. Therefore, before treatment begins, the patient should be accurately diagnosed.

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.

Malaria Prevention

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Photo by Matthew Naythons, MD

Malaria prevention consists of a combination of mosquito avoidance measures and chemoprophylaxis. Although very efficacious, none of the recommended interventions are 100% effective.

Mosquito Avoidance Measures

  • Because of the nocturnal feeding habits of Anopheles mosquitoes, malaria transmission occurs primarily between dusk and dawn.
  • Contact with mosquitoes can be reduced by remaining in well-screened areas, using mosquito bed nets (preferably insecticide-treated nets), using a pyrethroid-containing flying-insect spray in living and sleeping areas during evening and nighttime hours, and wearing clothes that cover most of the body.
  • All travelers should use an effective mosquito repellent. [Read more…]