Travelers to the countries affected by malaria usually do not have any background immunity to malaria since they are not routinely exposed to malaria in their own countries. As non-immunes, they are at high risk for malaria and its complications. Other particularly vulnerable groups include pregnant women, infants and young children, splenectomized and immunosuppressed individuals. The general rule for all high-risk groups should be avoiding any travel to malarious regions, if possible.
It has to be mentioned, that even in high risk areas, pregnant women and infants need to protect themselves from getting malaria because of the high mortality due to malaria in them.
Malaria prophylaxis targets:
An alternative or supplement to malaria prophylaxis is a 'standby treatment'. It is also referred to as a 'presumptive treatment' when traveler self administers antimalarials whenever malaria is suspected (feverish and unwell) in the place which is far from medical/diagnostic facility (medical care is unavailable within 24 hrs). Rapid standby treatment may be advantageous in people with increased risk for side effects of chemoprophylaxis (e.g. pregnant women, young children and people with drug allergies).
- reducing risk of contracting malaria
- minimizing risk of severe malaria
- avoiding fatal malaria
The spectrum of malaria prophylaxis tools include everything from mosquito bite protection to chemotherapy, screening of blood donors or transfused blood, malaria cross-infection in hospitals etc. Despite being very effective, malaria prophylaxis does not guarantee a full protection. Doctors have to alert all travelers to malarious regions about the risk of contracting malaria in spite of taking prophylaxis. Special awareness should be made if the traveler is at risk of getting falciparum malaria.
Mosquito bite prophylaxis is universal whereas the choice of chemoprophylaxis depends upon the travel destination, travel type and its duration.
The risk of infective mosquito bites can be avoided by staying indoors from dusk to dawn, because mosquito tend to bite more at night. House should be sprayed with insecticide (see vector control). Mosquito screens and bed nets impregnated with insecticides, such as permethrin, very effectively protect against bites. Long clothing should be worn out of doors after sunset. Cloth and skin repellents (e.g. DEET - N,N-diethyl-3-methylbenzamide) provide additional protection and very rarely result in skin allergy in case of DEET. However, when applied to the face it should be kept away from eyes and mouth.
Best options for chemoprophylaxis come out from evaluating the following factors:
Drug resistance profile of the travel area determines whether the use of chloroquine is appropriate. It may further narrow the drug choice depending on the presence of highly resistant strains (e.g. mefloquine resistance in border areas of Thailand and Cambodia).
Chloroquine is the prophylactic drug of choice in the regions without chloroquine-resistant P.falciparum. However, today the chloroquine-senditive areas of P.falciparum are relatively few including including parts of the Middle East, NIS of former Soviet Union, China, Mexico, Central America north of the Panama Canal, the island of Hispaniola, and temperate South America (see Table).
Contraindications and precautions for specific patient should be considered in choosing a prophylactic regimen. For example, when patient has a history of seizures or neuropsychiatric illness, would it be better to avoid Mefloquine? Or should the history of renal failure preclude Malarone use?
Risk-benefit analysis has to be applied in evaluating the Other factors such as tolerance, convenience etc. For example, if person gets severe photosensitivity on doxycycline, another option should be tried. Malarone is clearly attractive in that it only needs to be taken for 1 week instead of 4 weeks after travel (it is well known that after travel adherence to prophylactic drugs drops off). Finally, cost is an issue especially when malarone is chosen.
There are number of information sources today for travelers and their doctors about the area of travel and prophylactic treatment options available for them. We would recommend WHO's international travel and health website as a reference: www.who.int/ith
Furthermore, WHO has also a summary of malaria data by country available online at http://cisid.who.dk/mal/MALProfile.asp
CDC is also developping a user friendly map of the world where the malaria profile for all countries and malarious regions can be obtained. Current CDC's travelers' health website can be found at www.cdc.gov/travel
Below we also refer to the region specific summary table of chemoprophylaxis and standby treatment (see Table1).
Table1. Chemoprophylaxis and standby treatment for travelers in malarious areas
||Armenia1, Georgia (rural), Azerbaijan (rural), Tajikistan (South border), Turkey (Adona, Side, South East Anatolia, March-Nov), Egypt (El Faiyoum, June-Oct), Iraq (rural North, May-Nov), Syria (Northern border, May-Oct), Mauritus (rural)
||Afganistan (< 2000m, May-Nov), Iran (March-Nov), Oman, Saudi Arabia (except North, East & central provinces, Asir, West border cities), Yemen, United Arabian Emirates (rural North)
||C + P
||Sub-Saharan Africa including Sao Tome, Principe, Madagascar and Comoro Islands
||Mexico (rural), Central America, Haiti, Dominican Republic, Paraguay (rural, Oct-May), Argentina (North-West only)
||South America (except in E above and G, L below)
||C + P/Malarone
||Brazil (Amazonas, Mato Grosso, Maranhao), Colombia (< 800 m), French Guiana, Guyana (interior), Surinam (not Paramaribo and cost), Bolivia and Venezuela (Amazon regions only)
||South East Asia including some rural areas of China, Sabah (except in I and L below)
||Thailand, border of Cambodia and Burma (Myanmar) (except L below), western Cambodia
||South Asia (Indian subcontinent, Bangladesh - not Dhaka, Sri Lanka - not Colombo, Nepal Terai - not Kathmandu, Bhutan, Indonesia except K & L below)
||C + P
||West Pacific (Irian Jaya/Papua New Guinea & adjacent island, Solomon Island, Vanuatu)
||M/Maloprim3 + C
||North Africa & Middle East (except in A above); South East Asia - tourist areas and cities of Peninsula (West) Malaysia, Bali, Thailand, China, Sarawak, Hong Kong, Macao, Philippines, Brunei, Singapore, Maldives; South America - Uruguay
1 Ararat Valley was the risk area in late 90s. Today due to very low rates NO chemoprophylaxis is recommended.
2 For detailed prophylaxis regimen see Table.
3 Maloprim is the combination of Pyrimethamine and Dapson used against P.falciparum
C=Chloroquine; D=Doxycycline; F=Fancidar/Metakelfin; P=Proquinail; Q=Quinine; R=Riamet
According to the general principles of chemoprophylaxis:
- All prescribed drugs should be taken as advised
- Chemoprophylaxis should be started before the travel and continued upon return for the certain period of time depending upon the type of drug used
- If side effects are serious, the chemoprophylaxis must be discontinued and immediate medical advise is needed
- In the face of mild or moderate side effects the chemoprophylaxis may be continued but medical advise is needed
The following algorithm can be also used in choosing the appropriate chemoprophylaxic regimen.
Chloroquine is a standard choice of chemoprophylaxis in the areas of benign (e.g. Turkey) or sensitive P.falciparum malaria (see Table2-3. for detailed dosage for adults and children). Chloroquine is acceptable in pregnancy and in infants. One weekly dosage is quite convenient. Side effects are rare and, if happen, they may include dysphagia, nausea, blurred vision and itching.
There are currently 3 options available for the travel to chloroquine-resistant P.falciparum areas:
All three options are more effective compared to Chloroquine+proguanil. However, the latter may be chosen in selected circumstances (e.g. pregnant woman).
- Doxycycline taken daily starting 1-2 days before till 4 weeks after travel
- Malarone® (, taken daily starting 1-2 days before till 7 days after travel
- Mefloquine (Lariam®) taken weekly starting 1-2 weeks before till 4 weeks after travel
Mefloquine (Lariam ®) is an effective prophylaxis agent against chloroquine-resistant P.falciparum, apart from some regions in South East Asia, where mefloquine-resistance exists. It can be used in children from 5 kg of body weight and more than 3 months of age, although it is practically impossible to divide the 250-mg tablet into less than a quarter in order to adjust for the age group less than 2 years old. One weekly dosage is quite convenient. Mefloquine is contraindicated in pregnancy and lactation. Side effects include dizziness and gastrointestinal symptoms in about 5-10% of people. Neuropsychiatric complications including nightmares and vivid dreams have become the source of bad publicity on Mefloquine. However, such complications are likely to happen in less than 1% of people and they have not proven to be that significant or serious. It is sometimes recommended to begin Mefloquine a little bit earlier (3-4 weeks vs. 1-2 weeks) before travel in order to test tolerance.
Malarone ® (Proquanil+Atovaquone) is very effective in preventing vivax and multi-resistant falciparum malaria. Malarone should be taken once per day with food or milk product. After leaving the malarious area the treatment needs to be continued only for 7 days. Malarone is well tolerated. Major disadvantage is the high cost of the drug. It is currently labeled for use in children who weigh 11 kg or more. Up today, Malarone is not recommended for use in pregnancy and lactation just because there is no safety data available.
Doxycycline can be used for prevention of P.falciparum in South East Asia (multi-resistance) and also as an alternative agent for other areas. The regimen consists of one daily dose taken with meal, but NOT with milk or iron-rich products. Adverse effects of prolonged use may include gastrointestinal problems (e.g. diarrhea due to Clostridium difficile), vaginal candidiasis and photosensitivity. Women should be aware that contraceptive pills may become less effective when taken with Doxycycline. This drug is absolutely contraindicated in pregnant and lactating women as well as in growing children less than 12 years old.
Table2. Recommended chemoprophylaxis regimens
Table3. Dosage schedule for chloroquine chemoprophylaxis
||300 mg base (2 tab) once per week
||5 mg base/kg
||Chloroquine as above + proguanil 200 mg (2 tabs) once every day
||Chloroquine as above + proguanil 3 mg/kg
|Proquanil+Atovaquone (Malarone ®)
||100 mg proquanil + 250 mg atovaquone - 1 tab once every day
||Proquanil 2 mg/kg + Atovaquone 6 mg/kg
|Mefloquine (Lariam ®)
||250 mg base (1 tab) once per week
||5 mg base/kg1
||100 mg (1 tab/capsule) once per day
1 Not recommended for children < 1 year old
2 Contraindicated in children < 12 years old; 12-14 years - 0.75 tablet; > 14 years - 1 tablet/capsule
In all cases, continue chemoprophylaxis for 4 weeks after leaving the malarious area (except for Malarone - 1 week)
||Number of tablets per week
||Tablets, 100 mg base
||Tablets, 150 mg base
||< 4 months
Self administration of antimalarials in the absence of medical care may sometimes be very effective because of the following reasons:
Therefore, if the traveler is going to the malarious area which is remote from the medical care and diagnostic facilities, it is necessary to provide him with so called 'drugs in the pocket' for the standby treatment. It should be initiated whenever the travelers become feverish, and at least 7 days after entering the malarious area. All travelers should seek medical care as soon as possible following the standby treatment. For the reference on the particular standby regimen please see Table1.
- Malaria may progress rapidly to serious complications
- In high risk areas malaria chemoprophylaxis is only 50-90% effective
- In low risk areas side effects of chemoprophylaxis may overweight the benefit of avoiding malaria
© 2002. Malaria in Armenia.
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