Vaccine for malaria? Differences with yellow fever?

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QUESTION

Is there a vaccine to prevent malaria?
What is the difference between yellow fever and malaria?

ANSWER

In answer to your first question, no, there is not currently a vaccine available to prevent malaria. The best current candidate, the RTS,S vaccine which was developed by GlaxoSmithKline, is currently undergoing Phase III clinical trials in Africa. Although preliminary results showed up to a 50% rate of protection against malaria in some age groups, the trials will not conclude until 2014 and so full results will not be known until after that date.

As for your second question, while yellow fever and malaria are both transmitted by mosquitoes, they share few other similarities. Yellow fever is caused by a virus, for example, whereas malaria is caused by a single-celled parasite of the genus Plasmodium. The group of organisms that Plasmodium belongs to is often called “Protista” (the exact grouping and classification constantly changes!), and they more generally belong, based on cell type, to the Eukaryotes, an enormous group of organisms which also includes all mammals and even humans! Viruses, on the other hand, are tiny pieces of genetic material wrapped in a protein coating, and can hardly be described as alive in a conventional sense.

While both yellow fever and malaria are transmitted by mosquitoes, yellow fever is transmitted by the genus Aedes, whereas malaria is exclusively transmitted by the genus Anopheles (at least in humans, and all other mammals for that matter).While spraying inside households may reduce the prevalence of  both types of mosquitoes, Aedes mosquitoes tend to feed during the day, so sleeping under an insecticide-treated bednet is less protective against yellow fever than it is against malaria. Also, a vaccine is available for yellow fever (and has been available for over 50 years), whereas as I describe above, no such vaccine yet exists for malaria.

Finally, while superficially the symptoms of yellow fever and malaria may seem similar (fever, nausea, aches), other manifestations of the disease can be very different. Yellow fever is technically considered a hemorrhagic disease, since it can cause increased tendency to bleed in patients. Also, in some patients, the initial symptoms are followed by an acute liver phase, causing jaundice which can turn the patient yellow (and hence the name). Malaria can also affect the liver, and cause ild jaundice, but usually not to the extent of yellow fever.  Once a patient has been diagnosed with yellow fever, there is no specific treatment, and the patient is merely treated based on symptoms, to ease their discomfort. Vaccination is the mainstay of control of this disease, and has been very successful in many places; the total number of worldwide cases is estimated by the World Health Organization to be around 300,000, with 20,000 deaths, mainly in Africa.

The burden of malaria is also mainly felt in Africa, though the number of cases and deaths is vastly higher – globally, there are approximately 200 million cases of malaria in 2010, with almost 700,000 deaths. Along with the general symptoms of fever and nausea, the most dangerous manifestation of malaria is when it causes cerebral symptoms; this is usually only caused by Plasmodium falciparum malaria, and can lead to impaired consciousness, coma and even death. Also in contrast to yellow fever,  the mainstay of control is a combination of prevention (mostly with vector control, i.e. using bednets, indoor residual spraying and destruction of breeding habitats and larvae) and treatment (using a variety of medications).

Treatment of Malaria

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QUESTION

How is malaria treated?

ANSWER

Malaria can be a severe, potentially fatal disease (especially when caused by Plasmodium falciparum) and treatment should be initiated as soon as possible.

Patients who have severe P. falciparum malaria or who cannot take oral medications should be given the treatment by continuous intravenous infusion.

Most drugs used in treatment are active against the parasite forms in the blood (the form that causes disease) and include:

  • chloroquine
  • atovaquone-proguanil (Malarone®)
  • artemether-lumefantrine (Coartem®)
  • mefloquine (Lariam®)
  • quinine
  • quinidine
  • doxycycline (used in combination with quinine)
  • clindamycin (used in combination with quinine)
  • artesunate (not licensed for use in the United States, but available through the CDC malaria hotline)

In addition, primaquine is active against the dormant parasite liver forms (hypnozoites) and prevents relapses. Primaquine should not be taken by pregnant women or by people who are deficient in G6PD (glucose-6-phosphate dehydrogenase). Patients should not take primaquine until a screening test has excluded G6PD deficiency.

How to treat a patient with malaria depends on:

  • The type (species) of the infecting parasite
  • The area where the infection was acquired and its drug-resistance status
  • The clinical status of the patient
  • Any accompanying illness or condition
  • Pregnancy
  • Drug allergies, or other medications taken by the patient

If you have or suspect you have malaria, you should contact your doctor immediately.

Curing Malaria

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QUESTION

What is needed to cure malaria?

ANSWER

Malaria is usually cured through treatment with an anti-malarial drug. The World Health Organization recommends use of an ACT (artemisinin-based combination therapy, such as Coartem) as first-line treatment for all non-complicated (i.e. not severe) malaria, and especially P. falciparum malaria (which in most places is resistance to chloroquine, and also to mefloquine in some locations). For complicated, severe malaria, or in cases where the patient is unable to take medication orally, the recommended treatment is intravenous quinine.

Swelling of Lymph Nodes and Malaria

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QUESTION

I would like to know if swelling of lymph nodes in neck is any way connect to malaria?

ANSWER

Swollen lymph nodes are often a sign that the body is trying to fight off an infection, and so swollen lymph nodes are certainly sometimes observed in malaria patients. However, most malaria infections would also be associated with other symptoms, such as fever, chills, nausea and aches.

In some cases (but not all), malaria patients experience cyclical fever, whereby they have a high fever one day and no fever the next, but the fever returns on the third day, and the cycle continues. One type of malaria exhibits a cycle of fever one day, then no fever for two days, then fever returns on the fourth day. However, many patients do not experience these cycles, which means their symptoms are very similar to those for many other illnesses, which is why if you are in or have been visiting an area where malaria is transmitted and you have some of the above symptoms, it is very important to visit a doctor or clinic to get diagnosed for malaria. This can be done with a simple blood test, and the results are usually available very quickly. Then, if you are diagnosed as positive for malaria, the doctor can recommend appropriate treatment and instruct you in the proper way of taking it.

Treatment and Management of Malaria Parasite

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QUESTION

What are the treatments and management of malaria?

ANSWER

Treatment is actually part of the strategy for managing malaria, so I will come back to that later. The other main ways in which malaria is controlled is through prevention, diagnosis (followed by treatment if necessary) and education.

1) Prevention:

There are a number of ways to prevent malaria. These can be placed into two categories: medication and vector protection.

For medication, there are drugs you can take to prevent the malaria parasite from developing after someone is bitten by an infected mosquito. These drugs are known as “chemoprophylaxis.”

There are several different kinds, such as doxycycline, mefloquine (marketed as Lariam), atovaquone-proguanil (marketed as Malarone) and chloroquine—the type you use depends on the type of malaria present in the area. For example, in much of Africa and India, malaria is resistant to chloroquine, so this cannot be used as a prophylactic. In parts of Thailand, resistance to mefloquine has emerged. However, if the appropriate type of prophylaxis is used, it is very effective against malaria.

The problem is that these drugs have not been tested for long-term use, can be expensive and may have side-effects. Therefore they are of limited use for people who live in areas where malaria is endemic, and are more appropriate for travelers who are in malarial areas for short amounts of time. However, anti-malarial medication may be used in a very specific way for people at particularly high-risk for malaria, such as pregnant women and young children. In these cases, the high-risk individuals receive a dose or series of doses of malaria medication in order to prevent malaria. This form of prevention is known as intermittent preventive therapy (IPT).

Vector prevention involves protecting oneself against getting bitten by mosquitoes. This can involve wearing long-sleeved clothing in the evenings and at night, when malaria mosquitoes are most active, or wearing insect repellent on exposed skin. Indoor residual spraying, whereby repellent and insecticides are sprayed inside the house, can also be used to bring down the number of mosquitoes.

Another very effective technique for preventing malaria is to sleep under a long-lasting insecticide-treated bednet. The mesh acts as a barrier against the mosquitoes, and the insecticide impregnated in the mesh further repels the mosquitoes and prevents them from biting through the mesh.

2) Diagnosis

Diagnosis is considered a crucial step in controlling malaria, since it ensures that people are receiving correct medication, whether for malaria or for another condition which is causing their symptoms. Currently, the most commonly observed form of diagnosis is through microscopy of thick and thin blood films, which can be stained if necessary. These should be read by a qualified technician to determine both the species of malaria infection and the intensity of parasitaemia (number of parasites in the blood).

More recently, other methods for diagnosis have emerged. These include the use of rapid diagnostic tests (RDTs) which utilize a drop of blood applied to a reagent strip which very quickly reacts to show whether the patient is infected with malaria. While considered generally more sensitive than blood films, some RDTs don’t test for all types of malaria parasite, and many require that the reagents be kept cold in order for the test to be effective, which can be a problem in some developing countries.

Perhaps the most sensitive test for malaria is through PCR, which can theoretically detect a single malaria parasite in a drop of blood, and also determine the species. However, measures of infection intensity require an alternative form of PCR, called real-time PCR, which can be technologically challenging. All forms of PCR require a lot of expensive equipment and reagents, trained technicians and take several hours to run.

3) Treatment

Malaria treatment can be determined based on the diagnostic results, as well as other factors, such as:

  • The area where the infection was acquired and its drug-resistance status
  • The clinical status of the patient
  • Any accompanying illness or condition
  • Pregnancy
  • Drug allergies, or other medications taken by the patient

Most uncomplicated (i.e. not severe) cases of P. falciparum can be treated with oral medication, such as artemisinin-based combination therapies (ACTs). Artemisinin is given in combination with another anti-malarial drug in order to prevent resistance from developing in the parasite. Patients who have complicated (severe) P. falciparum malaria or who cannot take oral medications should be given the treatment by continuous intravenous infusion, with quinine recommended by WHO as the first-line treatment.

Other drugs, which are used in some settings, are considered second-line or alternative forms of treatment. These include:

  • chloroquine (very rarely used for P. falciparum, due to widespread resistance)
  • atovaquone-proguanil (Malarone®)
  • mefloquine (Lariam®)
  • quinine
  • quinidine
  • doxycycline (used in combination with quinine)
  • clindamycin (used in combination with quinine)

In addition, primaquine is active against the dormant parasite liver forms (hypnozoites) and prevents relapses, for patients with P. vivax or P. ovale malaria. Primaquine should not be taken by pregnant women or by people who are deficient in G6PD (glucose-6-phosphate dehydrogenase). Patients should not take primaquine until a screening test has excluded G6PD deficiency.

4) Education

Through education, people living in at-risk areas for malaria transmission can learn about ways to prevent the disease (see above), as well as what to do if they suspect they are infected (i.e. seek diagnosis). Similarly, education is important for travellers visiting malarial areas, so they know the best ways in which to avoid being infected.

Herbal Treatment for Malaria

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QUESTION

Can any form of malaria be treated by herbs or plants, and how long does it take to recover from malaria?

ANSWER

Actually, two of the most important kinds of anti-malarial medication are derived by substances found naturally in plants, though they need to be processed in certain ways before the full pharmaceutical effect is felt.

Quinine, administered intravenously, is currently the first-line treatment for complicated malaria (i.e. when the patient has a history of high fever, plus additional severe symptoms such as impaired consciousness). It is derived from the bark of trees of the genus Cinchona, which are native to the tropical rainforests of western South America. Long known to native populations for its medicinal properties, it became known to Europeans in the early 17th century when the Countess of Chinchón, the wife of the viceroy of Peru at the time, was cured by it, having been suffering from what was likely malaria.

Similarly, artemisinin, currently used in combination with other anti-malarial compounds as the first-line treatment against non-complicated malaria (these combinations are known as artemisinin-based combination therapies, or ACTs), is derived from wormwood, a shrub native to Asia but now found throughout the world. As with the Cinchona trees, traditional healers in China had used wormwood to treat fever for thousands of years, but its use had been forgotten in modern times, until its rediscovery in the 1970s. Nowadays, artemisinin is not recommended for treatment alone, as it is feared this will lead to resistance developing, and so it is only used in the combination therapies described above.

If treated promptly, and with the correct form of medication, recovery from malaria can take only a few days. If not, recovery can take much longer (even up to weeks), and in the case of P. falciparum malaria, the most deadly kind, the infection can become life threatening in only a day or two. P. knowlesi (found in parts of south-east Asia), though less fatal than P. falciparum, can also become severe rapidly, and so prompt treatment is especially necessary for these two kinds of malaria.

Malaria Beliefs

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QUESTION

How do beliefs and attitude affect the spread, treatment and prevention of malaria?

ANSWER

Accurate information and knowledge about how malaria is transmitted, diagnosed and treated is crucial to controlling the disease, for the general public living in malarial areas, travelers to these areas and health professionals. For example, many travelers are unaware that their destination is in a malaria transmission zone, so they do not take appropriate preventive precautions. Similarly, many travelers I have met believe that if they have had malaria once, they are immune and cannot get reinfected, so don’t bother protecting themselves from mosquitoes – this is not true, and they are inadvertently putting themselves at great risk.

In terms of endemic areas, the focus is on educating people about day-to-day preventive measures, such as sleeping under long-lasting insecticide treated bednets and indoor residual spraying. Educational campaigns that focus on simple, straightforward ways to prevent malaria are more likely to influence people’s attitudes and lead to better malaria control. Similarly, teaching people to seek accurate diagnosis and then ensuring they have appropriate treatment is an important step.

In some places, people feel they cannot afford to visit a doctor or clinic, or would rather place their trust in a traditional healer or healing herbs; since the most effective medications against malaria are treatments such as artemisinin-based combination therapies, which are available through official health sources such as clinics, believing in traditional medicine can lead to the malaria infection becoming very severe, and even resulting in death. As such, another component to control is making sure that medical services such as clinics are easily accessible even for the poorest people, provide good health care and are affordable.

How Long for Malaria Medication to Start Working?

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QUESTION

After I treat my body with the malaria pill how long will it be to start working in my body?

ANSWER

The malaria medication will start working almost immediately after you take it. The way in which malaria pills work differ depending on the type of drug you are taking, but most act on the parasites which infect red blood cells in your body. As soon as the parasite’s life cycle in the red blood cells is disrupted, you will begin to notice reduced symptoms and feel better, though it is important to take the full course of pills given to you by the pharmacist or doctor, as this ensures that all the malaria parasites are destroyed.

If you have recently taken medication against malaria, perhaps you would be willing to complete a short survey on our website, designed to get information about the experiences people have with malaria medication and the side effects they might have experienced? We would be very grateful for a few moments of your time – the link to the survey is here: Malaria Medication Side Effects Survey.

Headaches, Sweats, Nausea, Fatigue

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QUESTION

Since visiting Gambia I have been off food, suffering from headaches, sweats, nausea, tiredness and diarrhea after every meal, when I can eat that is. Do you think I should go to the doctor for a test for malaria?

ANSWER

Yes—whenever you have symptoms that include fever and sweats after visiting an area of high malaria transmission, it is always worthwhile getting a malaria test. With a positive diagnosis, the doctor can find out what type of malaria you have and then give you the most appropriate treatment. If the test is negative, the doctor is then able to look for other possible causes of your symptoms, such as an intestinal parasitic infection or some other illness.

Post-infection Malaria Medication

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QUESTION

My daughter has recently returned from a trip to Borneo. Even with aggressive preventive anti-mosquito behaviour (long sleeves/pants, deet applications and mosquito netting) but not anti-malarial medication, she received over 30 bites. She is now exhibiting some symptoms (body aches, headache and severe fatigue). She has an appointment at the doctors in 2 days time. Is there some kind of post-trip medication (like doxycycline) she can take as a precaution even if the malarial test comes back negative at this early of a time. Thanks.

ANSWER

The important thing to note here is that if your daughter has symptoms of malaria, then she should be diagnosed and, if positive, treated with medication aimed at curing active malaria. Doxycycline is NOT a drug used for the treatment of malaria, so there is no point taking it if she is already exhibiting symptoms.

Furthermore, some types of malaria found in Borneo (notably P. falciparum and P. knowlesi) can become more severe very quickly – 2 days may be too long to wait. If you live in an area where malaria transmission occurs, you may be able to buy a self-testing kit (also known as a rapid diagnostic test, or RDT) for malaria in a local pharmacy. Otherwise, if your daughter’s symptoms get worse, you should take her to an emergency room and explain her travel history and subsequent risk of having malaria.

There is no substitute for taking prophylactic malaria medicine; it might be that if your daughter had started taking prophylactic medicine as soon as she started receiving multiple mosquito bites, then she may have been protected to some degree. However, malaria has a latent period, and so she would have had to continue taking the medication for a period of time after returning home as well – with doxycycline, this means taking the drug for a further four weeks.