Repeated Malaria Cases, New Guinea

by

QUESTION

Hello, I live in Papua New Guinea. Myself, my wife and my 2 kids (both under 4 years old), get diagnosed with malaria approximately 3-4 times a year, usually vivax or falciparum. Our GP uses a prick of blood and examines under a microscope. Is it that easy/obvious to diagnose under this method and is it common to get this many attacks in a year? I also fear the affects of taking malaria tabs (eg Fansidar, Primaquin, Artemeter, Amodiaquine) this many times, especially for my young kids. Please help!

ANSWER

In high transmission areas, particularly in rural areas in sub-Saharan Africa, it certainly isn’t unusual for children to get as many a 5 or 6 malaria attacks in a year; adults tend to present with fewer clinical episodes, usually because they were heavily exposed as children and thus developed a significant level of immunity against malaria.

If you and your wife didn’t grow up in a malarial area, then you would not have that acquired immunity, and so you would be expected to get sick almost as often as your young children. Papua New Guinea certainly is a high transmission zone, and I think one thing which might help your family is to focus more on malaria prevention. Since malaria is transmitted by mosquitoes, the best way to avoid getting malaria is to avoid getting bitten by mosquitoes. You should all be sleeping under log-lasting insecticide-treated bednets, which kill and/or repel mosquitoes that try to bite you while you sleep (the mosquitoes that transmit malaria, of the genus Anopheles, are most active at dusk, at night, and at dawn—during the heat of the day they usually don’t feed, but may be found in cooler, heavily shaded areas).

You could also try spraying the walls of your house with a long-lasting insecticide like permethrin, which will also kill adult mosquitoes. Making sure your house is well-screened will also prevent mosquitoes from getting in and biting you at night and in the evenings, and if you are going out during these times, you and your family should wear long-sleeved clothing, and exposed skin should be covered with insect repellent. A DEET-based insect repellent is best, but you may not be comfortable using these regularly on young children, since it can have some potentially dangerous long-term effects, particularly on the liver.

In terms of your other questions, looking at your blood under the microscope is the normal way to diagnose malaria in many places, so it sounds like your GP is doing a good job. There is no indication of adverse effects from taking multiple, repeated doses of anti-malarials, but as I mention above, taking additional preventive measures may further help in reducing your family’s malaria incidence.

One thing you might want to talk to your doctor about is the fact that in some cases, Plasmodium vivax can cause relapses of infection weeks or even months after the initial infection. The reason is that P. vivax can form dormant life stages, which can hide out in the liver, and cannot be killed by the normal anti-malarial treatment. However, there is a medication, called primaquine, which can kill these liver forms, and prevent future relapse. People with a deficiency in a particular enzyme, called G6DP, may not be able to take this medication, as it may cause severe anaemia, so prior to taking the drug you might have to be tested for this deficiency. However, it is definitely something you should talk to your GP about.

Please take a moment to complete our Malaria Survey, as it will help us better understand the effects of malaria medications.

Malaria Prevention

by

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.

Malaria in Thailand: Phrae and Nan

by

QUESTION

We are traveling in Phrae and Nan (in Thailand) in the period of December-Januar. Is there any risk for malaria. We are travelling with kids (9 months, 6 and 8 year) and want to avoid risky areas. Can we travel safely in that region? Thank you for your reply.

ANSWER

Thanks for your question. Phrae and Nan are two districts in northern Thailand—the latter shares a border with Laos. While most of the very touristy destinations in Thailand (i.e. Bangkok and the coastal regions) are considered to have very low levels of malaria, and perhaps no transmission at all, I’m afraid that the areas bordering Laos, Myanmar and Cambodia do have malaria and so if you visit, you should take appropriate preventative precautions.

It is worth noting that some parts of Thailand are known to have mefloquine (sold as Lariam) and chloroquine resistant strains of malaria, although I have just looked it up and it doesn’t appear that Phrae and Nan are within these regions. However, it would still be worth seeing a physician or visiting a travel clinic to get specific advice for your family, and particularly what anti-malarials are appropriate for your children—a lot of that will depend on personal preference, such as how frequently you are comfortable taking medication and also how much you are prepared to spend.

Some, such as Lariam, are also frequently associated with side effects, which may affect your decision. If you do take anti-malarials on your trip, please take the Malaria Medication Side-effects Survey: Treatment and Prophylaxis. We are trying to collect information from travellers to record people’s experiences with the different types available.

In addition to preventative anti-malaria medication (known as prophylaxis), there are other preventative measures you can take, such as sleeping under a long-lasting insecticide-treated bednet, wearing long-sleeved clothing (especially in the evenings and at night when malarial mosquitoes tend to bite) and using insect-repellent on any exposed skin. You can also spray clothing with permethrin, a chemical which repels insects and prevents them from biting through thin cloth.

Three Attacks of Malaria

by

QUESTION

I am right now recuperating from a third attack in less than one year’s time. What could have gone wrong ?

I am awaiting to hear your advice.

ANSWER

There are a number of reasons for multiple malaria attacks. One is that although malaria can be easily treated, these treatments often don’t prevent re-infection. There are separate drugs which can be used to prevent malaria (known as malaria prophylactics), but these must be taken all the time to be effective (usually either once a week, once a day or twice a day, depending on the specific drug), and so usually aren’t appropriate (due to the unknown health risks of taking the drugs for that long, plus the prohibitive cost) for people living in areas where malaria occurs.

For people living in malarial areas, other means of prevention are required, of which avoiding being bitten by mosquitoes is paramount. For this, it is recommended to sleep under a long-lasting insecticide treated bednet at night, when many malarial mosquitoes are active. Similarly, wearing long sleeved clothing, especially if it is impregnated with an insecticide such as permethrin, can help avoid the bite of infected mosquitoes.

Second of all, there are some types of malaria which cause repeat episodes of illness, even after only a single infection. Specifically, Plasmodium vivax and Plasmodium ovale (the former is common in many parts of Asia in particular) can form life stages called hypnozoites which rest dormant in liver cells, even after the parasites in the blood have been cleared.

During this time, the patient will have no trace of malaria if they take a blood test, and they will feel fine. However, if these hypnozoites become active again, they will re-invade the blood, and the symptoms of disease will reoccur – at this stage, the parasite will once again be observable in the blood, and so the patient will be diagnosed as positive for malaria. As such, it is very important to find out what type of malaria you have, and if it is one of the above two species, then you can talk to your doctor about taking another type of medication, in addition to that which cures the blood infection, called primaquine—primaquine kills the hypnozoite liver stages of malaria and thus prevent recurrence of the disease.

Thanks for your question—since we think other people may benefit from the questions in this forum, I have removed your name and contact information to preserve your anonymity.

Recurring Malaria Long Term Effects

by

QUESTION:

Hi, my husband is an expat working in Mozambique for the past 5 years. He has been diagnosed with malaria 9 times, what are the long term effects of this and is he just unlucky or do others also get infected often? thanks.

ANSWER:

If the proper precautions are not taken, then it is very easy to get infected with malaria multiple times; I have one Ugandan colleague who claims he gets sick at least once a year from malaria, usually sometime in the rainy season. However, there are means to protect oneself from regular infection, and it might be that your husband could be more vigilant about such methods of prevention. For example, he should make sure he sleeps under a long-lasting insecticide treated bednet, which drastically reduced the risk of being bitten by mosquitoes at night. Similarly, he should try to wear long trousers and long-sleeved shirts, preferably impregnated with a substance called permethrin (an insecticide which prevents mosquitoes from biting through clothing – it can be purchased at most camping stores and sprayed directly onto clothing only, not onto skin), especially at dawn, dusk and at night, when malaria-carrying mosquitoes are most active. When mosquito numbers are high, he could also use insecticide that contains DEET on any exposed skin as a further precaution against bites.

The good news is that if his previous bouts of malaria have been uncomplicated, and diagnosed and treated quickly, there should be no long term effects of having had the infection.

Safety of Bed Net Insecticides

by

QUESTION:

Are the insecticides used on the bed nets safe? What are the brand names and chemical names of those insecticides, and can you point me to any studies that have been done to determine their safety?

ANSWER:

The short answer is yes, the insecticides used in bednets are safe under the conditions in which people are exposed to them through using bednets.

Most standard bednets are treated with a chemical known as a pyrethroid, and usually permethrin or deltramethrin. Both of these chemicals have low toxicity to most mammals and are poorly absorbed by the skin, making them safe for treating bednets. There are some studies on mice which suggest that pyrethroids such as permethrin can be carcinogens when ingested, though once bound to the fibre of a bednet the chemical is not ingested by the person sleeping under the net so this is not a danger.

The World Health Organisation maintains a comprehensive set of specifications (PDF) for maintaining quality and safety in insecticide treated bednets.

There is another WHO report on the safety of pyrethroids (PDF) for public health use, which gives more details about conditions under which these compounds are considered toxic and the risk of exposure through bednet use.

Malaria Prevention

by

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…]