MALARIA AND PROPHYLAXIS for the layman:




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    Default MALARIA AND PROPHYLAXIS for the layman:

    MALARIA AND PROPHYLAXIS for the layman:

    Dear fellow African travel enthusiasts and forum addicts. This is not light reading, but I hope will serve as a reference point for the perennial forum topic of malaria. If considered appropriate perhaps the moderators can make this a sticky.
    Malaria is a potentially fatal disease that can be prevented in the vast majority of cases by taking appropriate precautions to avoid mosquito bites and by taking effective prophylactic medications.
    It is a constant source of distress to some of us to witness, on this type of forum, the posting of opinions presented as facts, regarding malaria and especially prophylaxis. These alternate views often have no factual or scientific basis and one follows them at one’s own peril. Whilst accepting that this is a forum for the free exchange of opinions, any contrary opinion on malaria needs to accurately indicate that it is only a personal opinion and not a fact. Please, these alternate opinions should not be presented in such a manner as to persuade others to follow your personal bias and prejudices.
    The World Health Organization states “Malaria prophylaxis should be taken wherever the risk of acquiring malaria is higher than the (very low) risk of SERIOUS adverse reactions to chemoprophylaxis”.
    Below are some guidelines drawn up from scientific sources and totally evidence-based data. These are completely in line with recommendations from the WHO and our own Department of Health. These are only guidelines and not the final word. As in the rest of medical science, new scientific facts continue to emerge and I will endeavor to update any new developments. If any knowledgeable members note any omissions or inaccuracies of fact or emphasis, please come forward with them. However I am not keen that this thread be extensively used to debate what is official international policy.
    Always consult a Medical practitioner before taking any of the medications under discussion.

    INCIDENCE OF MALARIA:
    More than a million African children die of malaria every year. Malaria is the commonest cause of death in most parts of Africa. Most susceptible to SEVERE malaria are children (especially under the age of 5 years), pregnant women, the elderly and those with compromised immunity and serious medical illnesses. These people should avoid malaria areas if at all possible. In some tropical districts in Africa, over half of the residents may be infected with malaria.
    Malaria occurs in many areas commonly visited by our forum members. It occurs in some of northern SA, northern Namibia, north and central Botswana, Zimbabwe, Mozambique and the countries further north. Distribution maps are available on the internet. It does not occur above an altitude of 1,000 meters. It is important to remember that one often has to pass through a malaria area to reach some of the malaria-free areas. It is most common in areas of relative population density and during the rainy season. In times of particularly heavy rains its range may increase. The length of stay in a malaria area is significant; the increase in risk, comparing between a 2 week and 3 month exposure, is 6 times greater with the longer exposure (WHO). Malaria definately does occur out of the rainy season and prophylaxis should not be omitted because of the time of the year.


    DIAGNOSIS:
    It is imperative to make an early diagnosis and institute early treatment, as the onset of the severe form may occur within a day or 2. The severe form carries a very high mortality even under optimal care, usually due to multiple organ failure. The severe form involves some of the following; coma, kidney and liver failure, uncontrolled bleeding and difficulty with breathing.
    Classic symptoms are known to most of us. After exposure, any fever or flu-like illness must be regarded as possible malaria until otherwise proven. Intermittent fever, headache, cold shivers (rigors), tiredness, and muscle pains are well known symptoms.
    Less commonly known symptoms include abdominal pain, nausea and vomiting, diarrhea, anemia, confusion, drowsiness and jaundice. The symptoms can be particularly difficult to pick up in children. Suspect malaria in any child with malaria exposure, that seems out of sorts in any way.
    The incubation period is between 7 to 30 days after being bitten, but can be prolonged if prophylaxis has been incorrectly taken. The WHO states that it is a myth that prophylaxis delays the laboratory diagnosis of malaria. A malarial illness occurring despite prophylaxis is usually milder and this is where the confusion about the masking effect of prophylaxis originates. If you have become ill after a visit to a malaria area it is your responsibility to tell your doctor about your exposure, as specific tests, not used routinely, need to be done. If at first a malaria test is negative, this needs to be repeated at least daily until the diagnosis is made or you are better. A positive test is more likely during or just after a fever peak.

    BACKGROUND FACTS ABOUT MALARIA:
    Malaria is a parasitic disease spread by the bite of an infected female Anopheles mosquito. The males do not feed on blood. Human beings are the reservoir of the parasite, which mainly lives in our red blood cells. It is thus spread from an infected human to another by the bite of an infected mosquito. The Anopheles mosquito is fairly small compared to other mosquitos and its flight is not the noisy whine of local mosquitos. It is thus not easily noticed. Thus the frequent statement “we saw no mosquitos” holds no water. The bites are not as raised or itchy as those from our local mosquitos and may easily be overlooked. This mosquito looks like a fighter aircraft when at rest, with a head down, hind legs up posture. It has mottled markings on its wings. They breed in fresh standing water. Its flight is low to the ground and it seldom flies above knee height so that bites are most often on the lower limbs or when lying down. They are mainly active between sunset and sunrise, precisely when happy campers are relaxing outdoors, sitting with a drink in hand.
    The parasite is known as Plasmodium. There are 4 different species, of which Falciparum is the most severe and is what makes up virtually all the malaria cases in Southern Africa. The other types can occur in central and western Africa but are rarer. The information here is confined to Falciparum. The exact type of malaria is usually diagnosed on a blood smear. Resistance to the old type of prophylactics that many of us took in the 70’s and 80’s is widespread, but is very rare with precise use of the 3 medications discussed later.

    PREVENTION:


    General Measures:
    THESE ARE AT LEAST JUST AS IMPORTANT AS CHEMOPROPHYLAXIS.
    1) If possible avoid outdoor activity between dusk and dawn. (Not very practical).
    2) Be especially vigilant near areas of fresh standing water.
    3) Keep tents zipped up and screen doors closed.
    4) Spray the locality with household insecticides if you think mosquitos may be present. Use mosquito coils or mats in sleeping areas.
    5) Clothing. Especially after sunset it is very important to wear long-sleeved shirts and long trousers to cover exposed skin. Light colored clothing is less attractive to mosquitos. Because most bites are on the feet and ankles it is important to wear socks and avoid open shoes from dusk to dawn.
    6) Soak clothing and mosquito nets in Permethrin, an insect repellant with some insecticidal properties. This is available under various brand names at many outdoor shops. It is effective for up to 4 to 6 weeks even on clothes that have been laundered.
    7) Citronella skin applications are fairly effective but have to be reapplied every 40 to 90 minutes. Candles also have some repellant effect.
    8) DEET based skin applications and sprays are more effective. They should have at least a 30% concentration of DEET. Commonly available commercial products are Peaceful Sleep and Tabard. These must be applied to any exposed skin surfaces and must be reapplied as per instruction on the container, usually every 4 to 6 hours. Remember to reapply more frequently if getting wet or if in very sweaty circumstances. Beware of applying too much in children because of possible toxicity. The topical applications are probably more effective than the armbands.

    Chemoprophylaxis:
    All prophylaxis should be taken with meals to increase absorption. Resistance to Chloroquine is now widespread and many of the older prophylactics are no longer effective.
    There are 3 medications that have proven track records. The individual choice is fairly complex and should only be taken after a thorough medical assessment. The choice depends on the area being visited, activities being engaged in, medical background, cost factors and personal preference. They may interfere with the oral contraceptive, leading to a more productive holiday than you bargained for.

    MEFLOQUINE:
    Larium or the cheaper generic, Mefliam.
    This is a very effective prophylactic. As with the other 2, its effectiveness is well above 90%. Failures are most often to poor adherence to dosaging or poor absorption, for instance from diarrhea or vomiting. Compliance is good because it has to be taken less often and for a shorter period after leaving a malaria area than some of the others. With generics now on the market it is also more cost-effective. It remains the most widely used.

    DOSAGE:
    Adults: 1 tablet (250 mg.) once a week, each dose taken at the same time of the day. Starting dose 1 week before exposure. Continue for 4 weeks after last exposure (4 doses).
    Children: Not safe if younger than 3 months or if less than 5kg in weight. It can be obtained in liquid form for children in some parts of the world.
    15kg or less; 5mg per kg per week.
    15 to 19.9kg; a quarter tablet per week.
    20 to 29.9kg; half a tablet per week.
    30 to 45kg; 3 quarters of a tablet per week.
    More than 45kg; 1 tablet per week. (Adult dose)

    CONTRAINDICATIONS:
    First three months of pregnancy and probably if breastfeeding.
    Infants of less than 3 months or less than 5kg in weight.
    People engaged in pursuits requiring a high degree of fine co-ordination (Pilots, divers, operators of heavy machinery etc).
    Not safe in most epileptics
    Not safe in people with psychiatric disorders.
    Not safe with certain anti-depressant medication.
    If on any chronic medication always check with your doctor for possible cross reactions with Mefloquine (or if using any of the other malarial prophylactic medications)
    Previous severe side effects on Mefloquine.

    SIDE EFFECTS:
    Neuropsychiatric: These have received the most prominence and are the most common. Fortunately they are usually mild. They range from moodiness, depression, vivid dreams and nightmares, insomnia and the very rare frank psychosis. These almost always occur with the initial dose and settle rapidly if no further dosages are taken, whilst switching to another prophylactic. There is no evidence that the side effects become more severe or more prevalent with prolonged usage. It is thus suggested that if being used for the first time, Mefloquine is started 3 weeks before departure, so that there is time, if side-effects occur, to switch to another prophylactic and still obtain effective cover. Those people who have been happy on Mefloquine in the past should certainly continue to use it, as the likelihood of future side effects after previous problem free use, is absolutely minimal.
    Quinine: The most significant medical disadvantage of Mefloquine is the fact that it can have interactions with Quinine with a risk of potentially severe heart-beat irregularities. Quinine remains the mainstay of treatment for severe malaria, where it has to be used intravenously. Most doctors would only use these two together in a hospital high care setting on a heart monitor.

    DOXYCYCLINE:
    This antibiotic is as effective as the other 2 prophylactics but as with the others, there has been the emergence of some resistance in certain parts of Africa, mainly the central western areas. A travel clinic or tropical medicine specialist should be consulted if one is planning to spend time in these seldom visited countries. Doxycycline is relatively cheap. It has been most commonly used in epileptics, pilots and divers, where Mefloquine should not be used.
    SIDE EFFECTS:
    Sun sensitivity: This is fairly common and can lead to severe sunburn.
    Superinfection. Opportunistic infections such vaginal thrush and other fungal infections can spoil your holiday. This is due to the fact that this antibiotic destroys the “healthy” bacteria living with your body, enabling other more harmful organisms to grow to harmful levels. Fortunately this usually only occurs with prolonged usage and is not a serious health threat.
    CONTRAINDICATIONS:
    Pregnant (especially first 3 months) and breast feeding women. Also in children less than 8 years of age. In both instances because it has adverse effects on growing bones and teeth.
    DOSAGING:
    Adults. 100mg (1 tablet) every day, start 1 day before entering a malaria area and continue for 4 weeks after leaving.
    Children. 8 years or less, do not take. More than 8 years, 2mg per kg per day, take daily as in adults. Can be obtained in liquid form for children.

    MALARONE:(Malanil)
    Many feel that this has become the new gold standard. It has fairly recently been released in SA but has been in use for a fairly long time elsewhere in the world. Until the last few years it was recommended with some reserve because it was new and trials on its usage were still incomplete. Most doubts have now been resolved and its use is growing rapidly throughout the world. I have no doubt that if it were cheaper it would become the most commonly used malaria prophylactic. The patent should be expiring fairly soon and with the appearance of cheaper generics it will become the agent of choice for most.
    It is highly effective if taken strictly according to instructions and has the lowest side effect profile of the 3. But it is a fairly new product and time may reveal some unexpected effects, especially if used long term, where it has not been fully tested yet. The WHO has however recently approved it for long term use.
    SIDE EFFECTS:
    Minimal and minor. Do not be put off by the possible side-effects listed in the package insert. Pharmaceutical companies are obliged to list every possible side-effect reported. To keep a perspective a common household medication such as Paracetamol has a similar list.
    CONTRAINDICATIONS:
    Not to be used in children less than 11kg in weight.
    Not to be used in first 3 months of pregnancy.
    Surprisingly to me, the WHO state that it is safe to use whilst breast feeding.
    ADVANTAGES:
    Highly effective, even against the other 3 strains of malaria. No resistance appears to have emerged yet.
    Absolutely minimal side effects.
    Minimal interactions with other medications have emerged.
    DISADVANTAGES:
    Cost. This is the major problem. Its cost at present is at least double that of the other prophylactics. You will not get much change from R1,000 for the average course.
    It is only available in tablet form and has an unpleasant taste. Children have to take it crushed with some sort of sweet syrup to disguise its taste.
    Dosage is daily, causing problems with compliance.
    DOSAGE:
    Adults
    1 tablet daily (Atovaquone 250mg and Proguanil 100mg)
    Start 1 to 2 days before entering a malaria area.
    Continue for 7 days after leaving a malaria area.
    Children
    Paediatric tablets are available, start and stop taking as per adults.
    11kg or less, not to be used.
    11 to 19.9kg, 1 paediatric tablet daily.
    20 to 29.9kg, 2 paediatric tablets daily.
    30 to 39.9kg, 3 paediatric tablets daily.
    40kg or more, adult dose.

    MALARIA SELF TEST KITS:
    These are very useful as long as one understands their limitations. They uncommonly give a false positive result. False negative results are the problem, the reported rate varies tremendously, from 20 to 40%. The package instructions must be followed very precisely in order to avoid unreliable results. These kits are now widely available from travel clinics, outdoor outlets and pharmacies.
    The kits test your blood for the malaria parasite protein (antigen) and can be useful if there is no nearby facility to do a blood smear. A blood smear is the gold standard and must be obtained as soon as possible, even if it means a considerable detour. Even some of the smallest clinics in rural Africa can interpret these slides. Any delay in definitive treatment may result in the onset of severe malaria. Coartem as self-medication is only suitable for mild malaria. Its greatest use is as an initiation of treatment whilst heading for the nearest medical facility (see below).
    Most of these kits only test for Falciparum malaria, fine for most trips. If you are going to be in an area where the other types of malaria are present, it might be worth the trouble to hunt down a kit that tests for all the strains prevalent in that area.
    The kits cannot be used to monitor the response to treatment as can be done with smears, as the kit test remains positive for many weeks after cure has been acheived.

    COARTEM as self-treatment:
    This, as with the test kits, should be carried by all those travelling offroad in Africa. Coartem is a prescription drug which was originally discovered by the Chinese and has only recently become available. It is available from travel clinics and on prescription from pharmacies.
    Self-treatment is seldom a sound practice, but obviously the situation of the traveler in Africa may demand otherwise. Coartem has few side-effects and can usually be taken safely when malaria is suspected or suggested by a positive kit test. This is with the strict proviso that great effort is made to get to a facility where the diagnosis can be confirmed as soon as possible and definitive treatment for severe malaria can be instituted if needed. COARTEM IS ONLY SUITABLE FOR THE TREATMENT OF MILD OR UNCOMPLICATED MALARIA. There are also many other very dangerous tropical diseases that can initially imitate malaria. Do not leave seeking definitive medical help too late!
    Be sure to read the package insert carefully and in fact whoever issues it to you must be prevailed upon to give you a detailed briefing on it. There is obviously a danger to handing these tablets out to others in your group without knowing what to check for in their medical history.
    SIDE EFFECTS:
    It can cause an irregular heart-beat, so be careful in those with a history of heart disease or on any heart medication.
    Allergy can occur but is rare.
    CONTRAINDICATIONS:
    Infants less than 5kg in weight.
    Certain other medications such as heart medicines, anti-depressants, antibiotics and psychiatric medications may have adverse cross reactions.
    Probably not safe in pregnancy or when breast feeding.
    Unsafe in people with chronic kidney or liver disease.
    DOSAGE:
    Adults
    The standard adult dose is 4 tablets.
    Day 1, take first dose, repeat after 8 hours.
    Day 2, 1 dose morning and evening.
    Day 3, 1 dose morning and final dose evening.
    Children
    Do not use if less than 5kg
    5 to 14.9kg, 1 tablet per dose. Dose as per adult schedule.
    15 to 24.9kg, 2 tablets per dose.
    25 to 34.9kg, 3 tablets per dose.
    35kg or more, treat as for adult.
    COARTEM IS ONLY SUITABLE FOR THE TREATMENT OF MILD OR UNCOMPLICATED MALARIA. In severe malaria it may not be effective and if there is vomiting or diarrhea the tablets are unlikely to be absorbed adequately. If the patient vomits within 2 hours of taking the tablets, repeat the dose.
    The symptoms of SEVERE MALARIA requiring emergency evacuation may include:
    Fits, lowered level of consciousness, confusion.
    Breathing difficulties.
    Jaundice or urine the color of black tea.
    Bleeding.
    Patient becomes cold and clammy with a weak pulse.

    LONG-TERM PROPHYLAXIS:
    This is a very controversial topic. The recommendation of the Department of Health and the WHO is that prophylaxis should be taken long-term unless there are valid contraindications. They feel this should be done even if there seems to be a level of immunity. In their opinion, Mefloquine represents the best option on present information. It is felt that Malarone holds great promise for the future. These recommendations apply to those on prolonged visits and also to permanent residents in medium to high risk malaria areas. They suggest that in some areas prophylaxis should be taken only during the rainy season.
    They emphasize the general preventative measures.

    Further or confirmatory information:
    * http://www.doh.gov.za/docs/facts-f.html
    * National Department of Health www.doh.gov.za www.health.gov.za 012 312 0125

    * Amayeza Info Centre amayeza@amayeza-info.co.za 011 678 2332

    * University of Cape Town Medicines Information Centre
    micguest@uctgsh1.uct.ac.za 021 406 6783 or 021 406 6778

    * Medical Research Council www.malaria.org.za 031 203 4700

    * World Health Organization www.who.int/health-topics/malaria.html

    * Center for Disease Control www.cdc.gov/travel/malinfo.html

    * Malaria Info Line 086 1669943(Mozzie)

    I hope this proves useful for future reference. I must emphasize again that these are only guidelines and do not supersede the need for an appropriate medical consultation.
    Stan Weakley.

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