ABC of Malaria
By Dr Malcolm Henry, MBChB (Hons) (UCT) B.Pharm (Rhodes) Member of SASTM (South African Society Of Travel Medicine) Medicross Fish Hoek
Malaria is a common and potentially severe disease that is endemic in more than 100 countries worldwide. It is estimated that more than 125 million international travellers visit these countries every year, many of whom fall ill with malaria while in these countries and more than 10 000 fall ill on returning home. It is said that more than 3 million South African residents travel to malaria areas each year and are at risk of contracting malaria. Malaria kills over a million people annually, most of these children in sub-Saharan Africa.
Malaria is an acute febrile illness caused in humans by four main species of protozoan parasite Plasmodium: P. falciparum, P. vivax, P. ovale and P. malaria, with an incubation period of at least 7 days.) P. falciparum is the most severe and is associated with high morbidity and mortality and is responsible for over 90% of cases in sub-Saharan Africa. These parasites are transmitted to humans by the bite of the female Anopheles mosquito, which is most active between dusk and dawn.
Travellers are at higher risk of malaria complications as they have no immunity. Most cases of falciparum malaria in travellers occur as a result of their failing to take adequate precautions to prevent mosquitoes from biting, or because they take inadequate or no prophylaxis. The risk of acquiring malaria is determined by the intensity of malaria transmission in the area and season of visit, as well as the length of stay, type of accommodation, and likely activities between dawn and dusk.
When considering preventive strategies there are 4 main aspects to be considered, generally known as the ABC of malaria prevention: A – be Aware of the risk; B – prevent mosquito Bites; C – take appropriate Chemoprophylaxis; D – early diagnosis can be life saving.
Being aware of the risk means researching the area to which one is travelling by accessing maps of malaria areas, and/or consulting your Travel Health Practitioner.
Several maps are available on the net including: http//www.nc.cdc.gov/travel/ and http//www.who.int/ith/countries/en/.
No chemoprophylaxis is considered to be 100% effective, and measures to prevent being bitten by mosquitoes should be considered the mainstay of malaria prevention. Applying a DEET containing insect repellent to exposed skin; remaining indoors between dusk and dawn; wearing long-sleeved clothing, long trousers and socks; using insecticide-treated bed nets; spraying inside the house with aerosol insecticide at dusk; using mosquito mats or coils; ceiling fans or air-conditioners; covering doorways and windows with screens.
Chemoprophylaxis is individualized and needs to be discussed with your Health Practitioner: various factors are taken into consideration when choosing an agent e.g. area and time of travel, co-morbid diseases, previous reactions, whether high risk patient or not such as pregnant women or young children under 5 years of age. There are 3 prophylactic agents available currently: Mefloquine (Lariam, Mefliam), Doxycycline (Cyclidox, Doximal), Atovaquone-proguanil (Malanil). Each of these should be taken 48 hours before entering the area and continued for 7 days if Malanil and 4 weeks after if Doxycycline or Mefloquine. There is no scientific evidence to support the use of complementary, alternative and homeopathic preparations for the prevention of malaria.
All travellers should be warned that malaria must be suspected and diagnosis and treatment sought in anyone presenting with a flu-like illness after being in a malaria area, especially for up to 3 months thereafter, even if they have been fully adherent with their prophylaxis. This could be LIFE-SAVING. It is vital to be informed and prepared beforehand, and therefore visiting your travel health practitioner for a pre-travel medical and travel health advice is essential.