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• WHO - Risk by country (link)

• Antimalarial Drugs & Common side effects

• Drug dosages (including children)

MALARIA - Full Information

Introduction
Malaria is one of the 10 most prevalent and deadly diseases in the world. Between 300 to 500 million clinical cases occur every year with over 1.2 to 2.7 million deaths. 90% of these occur in sub-Saharan Africa. 800>1000 cases of malaria are reported in Australia each year. It is a parasitic disease spread by the bite of Anopheles mosquito which is active between dusk and dawn.   Malarial symptoms can occur after 8 days following an infected bite. The principal symptoms are fever, malaise, headache, chills and sweats but it can present as a respiratory or gastrointestinal illness.

Prevention
You cannot depend on medications alone to prevent malaria so avoidance of bites is the best plan. Consistent use of the measures below will also prevent other mosquito spread diseases particularly dengue (A daytime biting mosquito disease), as well as other insect or fly spread diseases.

Early diagnosis and treatment of malaria
Since few can escape mosquito bites during their travel and no preventative drugs are completely effective we need to accept the fact that you may contract malaria. Hence early diagnosis and treatment is essential.
Any fever occurring whilst away or after return from a malarious area, even if still taking preventative drugs, may be due to malaria, and you should consult a doctor, tell the doctor where you have been, voice your suspicion of malaria, and ask for a blood film to be done. You should do so within 48 hours of onset of fever, or earlier if you are very unwell.
(The very dangerous falciparum malaria usually occur within 3 months of return, but may be longer)

Minimisation of exposure to mosquitoes
Stringent measures to prevent mosquito contact reduce the risk of contracting malaria by ten fold.
They include:

• Mosquito nets preferably impregnated with permethrin-emulsifiable concentrate. Permethrin is an insecticide but not a repellent; is safe, colourless, odourless; is stable; adheres well to fabric; survives 5-10 washing's in hot or cold water; but is not recommended for skin application.
• Avoidance of night time outside activities.
• Avoid dark coloured clothing as it attracts mosquitoes as do perfume, cologne & after-shave.
• Clothing to cover arms and legs in the evenings. NB. It is common for mosquitoes to attack leg/ankle region.
• Use of an insecticide aerosol in the room to kill mosquitoes before retiring. (Knock Down sprays)
• Use of mosquito coils or vaporising mat containing a pyrethrin.
• Use of mosquito repellents. The most effective mosquito repellent is (DEET). "Rid" or "Muskol" are commercial preparations containing DEET. Roll-on preparations are recommended as spray cans may explode in luggage compartments. It is effective for 3 to 4 hours when applied to clothing or skin. It needs to be spread evenly and completely over all exposed skin. Untreated travellers in proximity to treated ones are more apt to be bitten.
• DEET is absorbed through the skin. Preparations containing less than 50% DEET are almost free of side effects when applied to the skin of adults. In children the repeated,  extensive inappropriate application of as low as 20% DEET has lead to staggers, agitation, tremors, slurred speech, convulsions and death.
• DEET repellents should be kept well away from plastics, including cameras, as it will dissolve them.
• In addition MASTA (Medical Advisory Service for Travellers Abroad) can provide a large range of travel equipment including impregnated mosquito nets, wrist and ankle insect repellent bands (mosi-guards). These products can be obtained through some chemists or by mail : MASTA PO Box 168, Dee Why, NSW 2099 Tel:(02) 971 1499 or Fax (02) 971 0239. TMVC and some camping stores can also supply these products. TMVC website www.tmvc.com.au ; also Travel Clinics, Australia www.travelclinic.com.au/products.htm

Malarial Risk Areas

Approximate fractions of adult doses of antimalarial drugs tor children

Chloraquine:- Prophylactic dose 5 mg/kg base/week, up to maximum adult dose of 300 mg base/week.

Mefloquine:- Prophylactic dose 5 mg/kg /week, up to a maximum of 250 mg. (Adult: 250 mg weekly)

Azithromycin:- 250 mg daily (Adult). Less effective than doxycycline, malarone & mefloquine but can be used in children and during pregnancy (also used to treat bacterial dysentry ** WHO )

Primaquine - not approved for prophylaxis in Australia
Consider if no other alternative: Adult dose 30mg base per day with food - Children 0.5mg/kg base taken with food.

Tafenoquine (very promising new once weekly primaquine like drug) - not available in Australia

Proguanil:- Prophylactic dose 3 mg/kg daily.(Adult. 200 mg daily)
nb. rarely used by Australian Travel authorities alone

Treatment doses  (nb. Riamet not approved for use in children under 12 in Australia)

Quinine + Fansidar:-
Quinine 600mg (10 mg/kg) every 8 hours for 7 days + 3 tablets Fansidar (Adult)

Quinine + Doxycycline:-
Quinine 600mg (10 mg/kg) every 8 hours for 7 days + 200mg Doxycycline daily 7 days (Adult)

Mefloquine:- Therapeutic dose:  3 tablets initially, then 2 tabs 6 - 8 hours later
(currently only used if no alternative)

Stand by Treatment
Since malaria can become life-threatening within a short time you should not delay seeking medical attention. Travellers who are likely to be more than 24 hours away from medical help, are often given one or more treatment courses of the following to take with them.

Business persons & Frequent Travellers
Some travellers make frequent short stops to endemic areas, over a prolonged period of time. Such travellers may eventually choose to reserve chemoprophylaxis for high-risk areas only. Malarone may be the most useful malarial prevention drug here, as it only needs to be taken for 1 week after leaving the malarial area. When antimalarial drugs are not used, rigorous self-protection measures against mosquito bites should be employed and they should be prepared for an attack of malaria: they should always carry a course of antimalarials for stand-by emergency treatment, seek immediate medical care in cases of fever, and take self-treatment if medical help is not available.*(*p 135 WHO 2002 year book - www.who.int/ith/chapter07_03.html#10)

Standby malarial treatment:

• Malarone (Atovaquone + Proguanil) - The dosage is 4 tabs daily for 3 days with food and is now considered the drug of choice. (but expensive approx $100 Aus). 
• Artemisinin derivatives: Riamet (Co-artemether which contains artemether 20mg and lumefantrine 120mg) - 4 tablets twice a day 3 days. Advantage of being very quick acting. (Supply - Not always available)

• Fansidar (3 tablets for an adult) - becoming less reliable

• Mefloquine for adults > 65kg, 3 tablets followed 6-8 hours later by another 1 tablet (high side effects & no longer recommended)

• Quinine (adult dose 600 mg three times a day for 7 days) - eg pregnancy
  see also WHO year book (Stand by treatment)- www.who.int/ith/chapter07_03.html#10

(Nb. If taking malarone for prevention, a supply of Riamet should be taken)

ICT Malaria P.f/P.v test  - This test, provides a realistic alternative for people in this category, particularly those who have had significant side-effects from either mefloquine or doxycycline. This test detects circulating antigens of falciparum malaria. A finger prick blood sample gives a result in 5 minutes. For Plasmodium falciparum infection the test is close to 100% reliable, but false positives can occur (rheumatoid factor, previously treated malaria in the last month). For vivax malaria reliabilty is very low. The test is stable at 37 degrees C for 4 months. Cost approx $30 for 2 test kit.  - NB. The test is very reliable in experienced hands but reliability in a sick febrile traveller (self testing) is questionable.
Last edited: 14-Sep-2005

Preventive drugs should be continued after treatment for malaria. As serious neurological side effects may occur when mefloquine is used in the high doses needed for treatment, it should only be used in a true emergency situation when medical attention is not available. Standby use of mefloquine is not recommended for persons already taking mefloquine for malarial prevention. (click important note ) -- Also see Full Information

Antimalarial Drugs & Common side effects ... Childrens dosages

Chloroquine: Minor side effects such as stomach upset and blurred vision occur frequently. These can lessened by taking tablets with food, or taking half the dose on 2 occasions each week. They are safe in pregnant women and children in correct doses. Pruritus (itch) in dark skin individuals is common. . If you have had generalised psoriasis, chloroquine and other chloroquine-like drugs, including primaquine, quinidine and proguanil should be avoided. Retinal changes including eye damage and blindness may occur after prolonged use but on the usual 300mg per week dose it would take 6-7 years.

Malarone:  - a combination of atovaquone and proguanil in a single tablet, is a new addition for malaria prevention. Its use has been approved for treatment and prevention of malaria (TGA-Australia) since November 2001. It is particularly useful where malaria is resistant to chloroquine and mefloquine (Larium). On evidence to date, it appears to be very safe and effective, but is expensive.

For prevention of malaria, Malarone is taken once a day, starting 1 day before entering malarial risk area and continuing for 1 week after leaving the malarious area. It should be taken with food or milk. This regime is simple and suited to business & frequent travellers.  Nb. When Malarone is used for malaria prevention, side effects are uncommon . However, nausea, vomiting, abdominal pain, and diarrhoea occur when higher doses of the drug are used for treatment. Convulsions and rash have rarely been reported.

Doxycycline: It is an alternative to mefloquine for short-term travellers. Doxycycline at 100 mg/day is approved for a period of up to 8 weeks only (NHMRC 1994) but is probably safe for longer use. Side Effects include thrush, stomach & bowel upsets, (particularly if medication is taken on an empty stomach) and sunlight sensitivity. The exaggerated sunburn reaction may be minimised by avoidance of sunlight, using sunscreen and taking the drug in the evening. Drinking copious quantities of water after swallowing the drug is recommended to reduce heartburn. Using Doxycycline may make the Contraceptive pill unreliable. The Therapeutic guidelines 2002 states that: "A second form of contraception is not necessary, but may be offered." & "Women who develop breakthrough bleeding might consider using barrier methods for the duration of antibiotic therapy". Discuss this matter with your doctor. (Nb. The non life threatening Vivax malaria can occur whilst on doxycycline)

Mefloquine: Side-effects ('Lariam') Minor side effects such as nausea, vomiting, heartburn and loose stools occur in about 20% of users, but this is no more frequent than with other antimalarials and usually subside with continued use. Taking ½ tab twice a week with food, and drinking copious water with medication will help reduce these.

Unfortunately mefloquine frequently produces annoying adverse neurological effects such as insomnia, vivid dreams, dizziness, mental clouding, anxiety and coordination problems. These are sufficient to interfere with daily activities in up to 10% of users and are probably aggravated by use of alcohol and cannabis.
Disabling side effects sufficient to recommend the cessation of mefloquine occur in 0.5% of users. However despite this, some  5 - 10% of users will stop the drug.  Consequently any person requiring a clear mind and good co-ordination should not use mefloquine. This may involve travellers to high altitude and definitely those contemplating aqualung (scuba) diving. Other contra indications include persons with a history of seizures, neuro-psychiatric disorder, the first 3 months of pregnancy and those with cardiac conduction problems. Women are advised to use contraceptives during and for 3 months after administration of mefloquine.

Mefloquine is probably best commenced 3 -4 weeks before entering a malarious area as it takes this long to build up to satisfactory blood levels. (half life of 21 days).  Also this provides time to detect those travellers that develop unacceptable side-effects and thus enable a change in medication. Commencing 1 or 2 weeks before departure is not adequate.
A recent report involving soldiers taking mefloquine 250mg daily for 3 days to enable a quick build up in blood levels was surprisingly well tolerated.
US authorities are prepared to use mefloquine for up to 2 years continuously in Peace Corps Volunteers overseas.

Serious neuropsychological side effects can occur when mefloquine is used in high doses. (click important note )
see also Malarial misconceptions: http://www.hc-sc.gc.ca/pphb-dgspsp/publicat/ccdr-rmtc/00vol26/26s2/26s2n_e.html or copy

Proguanil: One of the safest antimalarial drugs. Mouth ulcers is an annoying complication in up to 37% of travellers. (when taken with Chloroquine). Proguanil is taken 2 tabs daily, starting 1 day before entering malarial area and continuing for 4 weeks after leaving the area.  Chloroquine is taken 2 tabs weekly…. Confusing your tablets could be deadly.
Contrarily  to WHO recommendations, Australian travel physicians mostly limit the use of Chloraquine + Proguanil, to travellers unable to take mefloquine or doxycycline.

Antimalarial special considerations

see also SPECIAL GROUPS - http://www.who.int/ith/chapter07_04.html#12

After returning home
Malaria may still occur after using antimalarial drugs, sometimes months or years after your trip. It is important that you seek prompt medical attention (within 48 hours) for any fever, mention your travels and your concern about malaria, and ask for a blood film examination. If you are more than moderately unwell go to hospital emergency centre.

Information mostly taken from: "International Travel and Health" (WHO year book - internet only)
Australian Immunisation Handbook, 8th Edition - 9/2003 - Part1 - Part 2 & Part 3 (large pdf files)
Centre for Disease Control, USA -  www.cdc.gov/travel Travel Health Seminar Oct 96, June 97,Feb 98, March 99, May 2000, August 2002 & March 2005 - Victorian Medical Postgraduate Foundation.
Manual of Travel Medicine, Melbourne, Oct 2004. Updated 06/09/2006.  Additional references & disclaimer.