If you are traveling to almost any tropical country these days it is likely you will need to be careful about malaria. This is a disease which was supposed to have been eradicated by now but instead is on the increase. Resistant forms of malaria have now spread to most of the developing world.
Since it is spread by mosquitoes, protection against them is the vital first step in preventing the disease. Malaria-bearing mosquitoes tend to be rural and are night-biters. Covering up with long sleeves and long trousers in the evening and early morning are, therefore, recommended. At night, it is best to have screens on the windows and bednets around your bed. There are a number of safe and effective insecticides to use on clothing and bednets and around the room as well.
Personal protection should also include an insect repellent on exposed skin. The only one of proven effectiveness is DEET. Others are of only anecdotal benefit or last too briefly to be protective. (See article on DEET.)
Once you have protected yourself in these ways it is time to think of medication to protect yourself against the disease per se. Unfortunately the malaria parasites get into your body and into your liver so quickly that it is not practical to actually PREVENT you from getting malaria. It is only possible to keep you from getting sick from it. This is why most anti-malarials need to be taken before exposure and continued for a period of time after you leave. The medicine needs to be in your blood stream as the parasites exit your liver and head into your blood cells. This can continue to occur for some time after you have been bitten.
The old standby for malaria prophylaxis is chloroquine. Its advantage is that it has established safety in almost all circumstances including use in children and pregnant women. There are several dosage forms including, in Europe, a liquid formulation for children. Also it is cheap and, at usual doses, has few side effects (nausea, headache, rarely blurred vision.) The effective dose needs to be calculated based on body weight and the brand of medication one is using so is best prescribed by a travel medicine specialist (like us!) The problem with chloroquine is that it is now useless against resistant strains almost all over the world.
A widely recommended back-up regimen is a combination of proguanil (Paludrine) and chloroquine. This, too, is cheap and is safe in pregnancy. But it is now at best 70% protective and probably even less so in most places. Also, since it needs to be taken daily it has more side effects and is less apt to be taken.
The drug currently recommended most by travel medicine specialists is mefloquine (Lariam.) Lariam has received some bad press in the past few years so you will probably meet some travelers who are aghast at your taking it. The best studies, however, still show it to be as safe as any other alternative and far more effective. It is still by far the recommended choice of the Centers for Disease Control. You can't take it, however, if you are on any psycho-active medicines (antidepressants, anxiety medicines) or have a history of any neurologic disorder. Women are more apt to have side effects than men with this drug, and sometimes a reduced dose is recommended for women. It is also not recommended for people with certain heart conditions or for divers, or for pilots and others who need excellent eye-hand coordination.
Lariam, just like chloroquine, quinine and most other effective antimalarials, can depress heart function if given in high doses. The usual preventive doses are much safer. The problem is that malaria REALLY aggravates angina and depresses cardiac function (by destroying red blood cells) so it is hard to tell how much of the problem is from the drug and how much is from the disease. The literature cites the actual cardiac risk at less than 1% but does warn that the risk goes up if one is already taking a beta-blocker (e.g. propranolol) or another anti-arrhythmia drug.
Another drug which is frequently recommended is the antibiotic doxycycline. This has the advantage of being relatively inexpensive, but must be taken daily during exposure and for four weeks after, and can result in some significant side effects such as upset stomach, a severe sunburn and vaginal yeast infections. It is effective (so far) against the chloroquine-resistant strains.
Two other medications new on the market and being recommended where available are azithromycin (Zithromax) and Malarone (a combination drug.) The former has still not undergone enough testing to warrant routine use. The latter is now widely available and in increasing use. It, too, must be taken daily, starting a day or two before exposure. But as it attacks both the blood and liver forms of the parasite it need be taken for only seven days following exposure. Malarone also has a very benign side effect profile. It is still quite expensive, but for short trips it is now frequently as drug of choice.
Unfortunately, there are already reports of malaria resistance to mefloquine in the Far East and the Pacific, and to Malarone in Africa. No drug, it appears, is going to remain totally effective for very long. Research continues on new drugs and there is still hope for a malaria vaccine, but this remains several years in the future.
In any case, malaria prophylaxis is a serious subject and should not be taken lightly. The Centers for Disease Control in a report in 2000 indicated that the number of malaria cases in the U.S. has risen by about 45% per year in recent years and that 80% of those getting malaria were either taking no medical prophylaxis or had been prescribed an inappropriate medication. Your malaria prophylaxis needs to be prescribed by a medical professional who is familiar with all the available medications as well as current resistance patterns, your personal itinerary and your particular health needs,
For people who anticipate a short stay and minimal exposure to malaria perhaps it is as effective simply not to take prophylaxis but to go promptly to a Travel Medicine clinic if they run a fever upon returning. For others who may get ill a long way from a hospital it might be a good idea to simply take along a course of anti-malarial medication in treatment (not preventive) doses to treat themselves if they get sick. Since malaria can be difficult to diagnose and the medication side effects significant, this is rarely recommended.
Finally, remember that NO type of malaria prophylaxis is 100% effective. Even if you took all your medicine as prescribed you can STILL get malaria and should see a doctor if you run a fever after returning from a malarious area.