Reoccurring Malaria

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QUESTION

Can malaria reoccur year after year from a single infection? I have been told that it comes back every year by many people. I have had malaria once and it never came back after successful treatment. My thinking is that once the parasite has been eliminated from the system it is gone unless you get bitten again.

ANSWER

There are several different types of malaria that infect humans, and two of these species (Plasmodium ovale and Plasmodium vivax) can recur from year to year after a single infection.

The way it happens is that these types of malaria are able to form dormant life stages which hide in the liver. Most malaria medication only targets the blood stage form of malaria, and so these liver stages escape being killed by the medication, and can survive for long periods of time without the patient knowing about them. Then, at some point later (no one knows exactly what triggers the relapse—there is evidence that infection with other forms of malaria can instigate relapse, or being bitten by mosquitoes, or even just the climate), the liver stages activate again and re-enter the blood stream, which causes a renewal of symptoms.

It is possible to prevent these relapses—there is one type of medication, called primaquine, which is able to kill the dormant liver stages and thus completely clear the patient of malaria. However, it is important to talk to your doctor before taking primaquine, as it is not suitable for some people (especially those with G6DP deficiency).

Apart from these two types of malaria, the other three forms that infect people (P. falciparum, P. malariae and P. knowlesi) cannot reoccur in the same way as described above – if you have been infected with one of these, and then been successfully treated, you cannot get the disease again unless you are bitten by another infected mosquito.

Malaria Prevention

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QUESTION

What are the ways in which you can prevent yourself from being infected with malaria?

ANSWER

Malaria prevention consists of a combination of mosquito avoidance measures (since malaria is transmitted by infected mosquitoes) and chemoprophylaxis (medication to prevent the establishment of malaria in your body, if you do get bitten). 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.
  • The most effective repellent against a wide range of vectors is DEET (N,N-diethylmetatoluamide), an ingredient in many commercially available insect repellents. The actual concentration of DEET varies widely among repellents. DEET formulations as high as 50% are recommended for both adults and children older than 2 months of age (see the Protection Against Mosquitoes, Ticks, and Other Insects and Arthropods section later in this chapter). DEET should be applied to the exposed parts of the skin when mosquitoes are likely to be present.
  • In addition to using a topical insect repellent, a permethrin-containing product may be applied to bed nets and clothing for additional protection against mosquitoes.

Chemoprophylaxis

      • All currently recommended primary chemoprophylaxis regimens involve taking a medicine before travel, during travel, and for a period of time after leaving the malaria endemic area. Beginning the drug before travel allows the antimalarial agent to be in the blood before the traveler is exposed to malaria parasites.
      • Presumptive antirelapse therapy (also known as terminal prophylaxis) uses a medication towards the end of the exposure period (or immediately thereafter) to prevent relapses or delayed-onset clinical presentations of malaria caused by hypnozoites (dormant liver stages) of P. vivax or P. ovale. Because most malarious areas of the world (except the Caribbean) have at least one species of relapsing malaria, travelers to these areas have some risk for acquiring either P. vivax or P. ovale, although the actual risk for an individual traveler is difficult to define. Presumptive anti-relapse therapy is generally indicated only for persons who have had prolonged exposure in malaria-endemic areas (e.g., missionaries, volunteers).
      • In choosing an appropriate chemoprophylactic regimen before travel, the traveler and the health-care provider should consider several factors. The travel itinerary should be reviewed in detail and compared with the information on where malaria transmission occurs within a given country to determine whether the traveler will actually be traveling in a part of the country where malaria occurs and if significant antimalarial drug resistance has been reported in that location.
      • The resistance of P. falciparum to chloroquine has been confirmed in all areas with P. falciparum malaria except the Caribbean, Central America west of the Panama Canal, and some countries in the Middle East. In addition, resistance to sulfadoxine–pyrimethamine (e.g., Fansidar) is widespread in the Amazon River Basin area of South America, much of Southeast Asia, other parts of Asia, and in large parts of Africa. Resistance to mefloquine has been confirmed on the borders of Thailand with Burma (Myanmar) and Cambodia, in the western provinces of Cambodia, in the eastern states of Burma (Myanmar), on the border between Burma and China, along the borders of Laos and Burma, and the adjacent parts of the Thailand–Cambodia border, as well as in southern Vietnam.
      • Additional factors to consider are the patient’s other medical conditions, medications being taken (to assess potential drug–drug interactions), the cost of the medicines, and the potential side effects.

The medications recommended for chemoprophylaxis of malaria may also be available at overseas destinations. However, combinations of these medications and additional drugs that are not recommended may be commonly prescribed and used in other countries. Travelers should be strongly discouraged from obtaining chemoprophylactic medications while abroad. The quality of these products is not known, and they may not be protective and may be dangerous. These medications may have been produced by substandard manufacturing practices, may be counterfeit, or may contain contaminants. Additional information on this topic can be found in an FDA document

Purchasing Medications Outside the United States.

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.

Distribution of Malaria

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QUESTION

Where does malaria mostly take place?

ANSWER

Malaria is mainly transmitted in tropical regions of the world; while some transmission does occur outside of the tropics, it tends to be seasonal in these areas (i.e. usually only during periods of high temperature/high rainfall). Within the tropics, malaria is found on all continents, though the highest number of cases is in Africa, which is also where over 90% of deaths due to malaria occur (of these, most are children under the age of 5). Outside Africa, the next highest levels of malaria are in India and south-east Asia and the western Pacific (such as Papua New Guinea).

Mosquito Types

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QUESTION

How many types of mosquito are there?

ANSWER

There are over 3,500 species of mosquito! However, most of these do not transmit any diseases to humans. Mosquitoes are usually divided into two sub-families, the Anophelinae and the Culicinae. The latter group consists of about 40 genera, including Culex and Aedes, which contain some species that transmit diseases to humans (such as yellow fever, dengue fever and West Nile). The former contains the genus Anopheles, which are the mosquitoes that transmit malaria. There are about 460 described species of Anopheles mosquito, of which about 100 can transmit malaria, though the vast bulk of transmission is usually limited to about 30 species.

Sexual Transmission of Malaria

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QUESTION

Can malaria be transmitted by having sex with an infected person?

ANSWER

No. Malaria cannot be transmitted sexually. It is only present in the blood and in certain organs such as the liver and spleen. As such, it is usually only transmitted via the bite of an infected mosquito, though in rare cases, it can be transmitted directly via blood transfusion, organ transplant or via the placenta during pregnancy (called congenital malaria).

Sexual Intercourse During Malaria Infection

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QUESTION

Can one have sexual intercourse during malaria infection?

Can malaria be transmitted by sexual intercourse?

ANSWER

Malaria cannot be transmitted by sexual intercourse. It is usually transmitted via the bite of an infected mosquito. Because the parasites infect red blood cells, malaria can also be transmitted via blood transfusion (if the blood is not screened beforehand), organ transplant, and from a mother to her unborn baby, either during childbirth or via the placenta.

Complete Course of Anti-Malarial Drugs

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QUESTION

Hi, I am in Goa and so far have not been bitten by anything. I am taking anti malaria tablets which I do not like. My question is this. If I do not receive any bites do I need to complete the course when I get home?

ANSWER

It is always better to complete the course of anti-malarials, just in case you actually did get bitten but just did not notice it. However, in some cases, the side-effects of anti-malarials can be uncomfortable and unpleasant, so I understand your dilemma. Just remember that there is always a risk of contracting malaria if you stop your anti-malarials early.

We at MALARIA.com are very interesting in learning about people’s experiences with anti-malarial drugs. Please take a few minutes to complete our Malaria Survey. All answers are anonymous and we will post the results on MALARIA.com.

Is it possible to inherit malaria?

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QUESTION

I was wondering is it possible for a father who contracted malaria in the Korean War to pass it to his unborn child.

ANSWER

No. Malaria can only be transmitted by the bite of an infected mosquito, and in rare cases, through infected blood, for example from a blood transfusion or organ transplant. Mothers can transmit malaria to their unborn babies via the placenta or through blood during childbirth (this is called congenital malaria) but there is no way that a father could pass malaria on to his child.

Malaria in KwaZulu Natal

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QUESTION

How many people are infected by malaria in KZN?

ANSWER

By “KNZ” I assume you mean KwaZulu Natal (for the benefit of other readers, this is a region of South Africa, in the north-eastern portion of the country). KZN is one of the few parts of South Africa that experiences malaria transmission, though effective control measures have reduced its impact as a public health threat.

Up until 1996, South African policy had been to use DDT (even though it was a banned substance) to control mosquito populations, and malaria levels had correspondingly been low. However, after cessation of spraying with DDT, the number of malaria cases increased, to a high of over 40,000 cases in the 1999/2000 malaria season (in KZN, malaria is most commonly transmitted during the wet summer months, from November to May). Since then, the use of DDT as an insecticide has been reintroduced (along with other public health measures, such as switching to artemisinin-based combination therapies for first-line malaria treatment), and the burden of malaria has plummeted.

The most recent data I could find reported less than 3500 cases for the 2001/2002 malaria season, and zero cases in 2002/2003 (though the data I found were only up to February 2003). Efforts to coordinate malaria control between South Africa, Mozambique and Swaziland have also contributed to the success of reducing malaria transmission in the region.