As divers, our quest for clear, warm seas and productive coral reefs often takes us to the tropics; indeed, many of the planet’s most exciting dive destinations line up like a dot-to-dot map along the equator. But excellent diving is not the only thing these destinations have in common — many tropical and subtropical regions are also home to malarial mosquitoes. Caused by plasmodium parasites and transmitted by the female Anopheles mosquito, malaria is a serious and sometimes fatal disease that affects the red blood cells and liver. It is prevalent throughout large areas of Africa, Asia, Central and South America, the South Pacific and the Middle and Far East.
There are several different strains of the disease; the one caused by the plasmodium falciparum parasite is the most dangerous. In 2010, the World Health Organization estimated that over 2 million people contracted malaria worldwide, of which up to 1.2 million cases proved to be fatal. Your chances for infection are highest at dawn and dusk when malarial mosquitoes are most active; signs and symptoms include chills, sweating, shivering, body aches and high fever. Complications can include circulatory collapse, kidney failure, jaundice and fluid in the lungs. Those victims who contract the falciparum parasite strain may experience an obstruction of blood flow to the brain, causing impaired consciousness, seizure and eventually, coma.
The seriousness of contracting malaria is such that divers traveling to malarial regions must take preemptive precautions. This article will explore the different options available to travelers, but should not be taken as medical advice: you must consult your physician before choosing which medication is best for you. Several kinds of malaria prophylaxis are available, all of which have varying side effects, and some may be more or less suitable depending on your destination, age, other medication and personal circumstances. If you’re planning a trip to a malarial area, you should contact your physician several weeks before your departure, firstly because many medications require advance dosing, and secondly because your pharmacy or clinic may need to order stock. Make sure to let your doctor know that you will be diving on your vacation, because this will affect his or her recommendations as to which pills you should take.
There are four main types of malaria medication: chloroquine, mefloquine (often sold as Lariam), doxycycline and Malarone.
- Chloroquine was the first anti-malarial treatment, and the disease has built up a resistance to it in many parts of the world, therefore rendering it ineffective in those locations. There are still some countries in which it can be used, though, mainly in the Caribbean and Central America. It is taken weekly for the duration of your vacation, as well as for the week prior to departure and for four weeks after your return. It is one of the few anti-malarial drugs with no recorded adverse affects on pregnant women, although expectant mothers are advised against diving in the first place. Side effects can include stomach upsets, headaches, dizziness, blurred vision and itching, and there are several medical conditions and other drugs with which chloroquine is not compatible.
- Mefloquine, or Lariam, is one of the cheapest anti-malarial drugs available, and like doxycycline and Malarone, is effective in countries where the malaria parasite has developed a resistance to chloroquine. However, it has some relatively severe side effects, including nausea, vomiting, dizziness, insomnia, nightmares, blurred vision and an altered sense of balance. In rare cases, mefloquine has been reported to trigger seizures, depression, anxiety, hallucinations and psychosis and is not recommended for those engaging in activities requiring fine coordination and spatial discrimination. For these reasons, and because symptoms can both imitate and exacerbate those of decompression sickness (leading to a failure to detect the latter condition), mefloquine is not recommended for scuba divers.
- Doxycycline is an effective anti-malarial drug and is often recommended as an alternative to mefloquine and chloroquine. Its list of side effects is not as severe as those of other drugs, but divers should be wary of its tendency to increase photosensitivity, thereby making the user susceptible to severe sunburn. Obviously, when spending a lot of time in hot countries in swimwear, this is a side effect that needs to be taken seriously. For women, doxycycline can increase the likelihood of yeast infections, another consideration that those prone to this condition should discuss with their physician. Doxycycline is taken throughout your vacation, and for two days before departure and four weeks after return, and is not suitable for children under 12 years of age.
- Malarone contains a combination of atovaquone and proguanil, and must be taken with food for two days before your vacation and one week afterwards. Traditionally it’s been the most expensive of the anti-malarial drugs, but has recently become much more affordable with the advent of a generic version of the pill. Serious side effects or reactions to Malarone are rare, although users could experience mild abdominal pain (especially if taken on an empty stomach), nausea, vomiting, headaches or diarrhea. This drug is not recommended for pregnant or lactating women, but is available in a dosage safe for children.
Remember — your partner, friend or family member’s choice of malaria pill may not be the best choice for you. It is imperative that you seek professional medical advice before making your decision; a doctor must usually write out a prescription anyway. The side effects of anti-malarial drugs may seem daunting, but the potential ramifications of not taking them are worse — DAN advises that “if a diver is unable to take a preventive medication because of side effects, the trip should be canceled or the medication changed to ensure coverage; the risk of contracting malaria is simply too great.” DAN also advises caution and stability on the drug before attempting to dive.
Divers should also be aware that malaria pills do not provide guaranteed protection, so make every effort to avoid being bitten in the first place. It is a good idea to travel with mosquito coils and a mosquito net in case your accommodation either doesn’t have them or has ones that are in bad repair. Try to cover arms and legs, particularly in the evenings and early mornings, and always use mosquito repellent. Preferably, choose a brand of repellent with at least 30 percent Deet, and reapply upon exiting the water. In many parts of the world, avoiding mosquito bites is a good idea not only as a precaution against malaria, but also against other mosquito-borne diseases like dengue fever, for which there are no pills or vaccinations.
Upon returning from your travels, be aware that malaria can manifest for up to a year after you get home. If you do experience symptoms including fever, chills, muscle aches and weakness, you should seek medical attention and remember to let your doctor know that you have been in a malarial country. Always remember to finish your course of pills, even after you leave the affected area. Don’t let the risk of malaria put you off traveling to the tropics; after all, this is the home of some of the best dive sites in the world. However, it is vital that you give the disease the respect it deserves, and take every precaution to ensure that malaria doesn’t ruin the trip of a lifetime.