Malaria update

Malaria just doesn’t get respect. Until, that is, someone catches it.

It is a wicked disease which infects between 300- and 550-million people (yes, that is one-third to one-half billion people — about 10 times the number of those suffering from AIDS) and kills between one to three million annually. It is spread by mosquitoes and is found through much of the world but primarily occurs in the tropics.

There are four species of this parasite which affect mankind. The most dangerous is called Falciparum, but the most common form is called Vivax, which can hibernate for months to years in the liver.

Malaria is a highly successful parasite which has infected the blood of humans for millennia. Sadly, since the majority of the people on Earth who suffer from it are poor and disenfranchised, little attention is paid to it in the developed world and many medical schools give the topic short shrift (as with most tropical diseases) and so American doctors know little about it.

The disease is, for the most part, curable. If caught promptly and treated appropriately, patients do very well. However, there is no real immunity to the disease, so you can catch it more than once.

The risk of infection depends upon several factors. The main ones are the destination, the season, the number of bites and the timing of the bites. Malaria can be contracted in cities as well as the countryside; however, the major cities of Latin America and Southeast Asia can be considered malaria-free, whereas this is not true for Africa nor the Indian Subcontinent.

The risk within a country can vary greatly, with some areas being completely free of the disease and other parts intensely rife with it. The mosquito that carries malaria is a bit of a vampire, biting from dusk to dawn. One does not get malaria from day-biting mosquitoes, but one could get other diseases from them such as dengue fever.

Avoiding malaria is shockingly simple. There are only two things needed: avoiding bites and taking antimalarial medication when in a risk zone.

Avoiding bites, otherwise known as Personal Protective Measures, involves wearing appropriate clothing, not wearing colognes or perfumes, sleeping inside an air-conditioned room or otherwise under a mosquito net, and wearing effective mosquito repellents.

Just as important to avoiding bites is taking an appropriate malaria preventive medication, officially known as “chemoprophylaxis.” The medication is taken to avoid dying from malaria and to reduce serious infection; no medication confers 100% protection against illness. Because of the complex life cycle of the parasite, any antimalarial medication must be taken for a set period of time after leaving the risk area.

In the United States we have four medications available to us for prevention (it is a different story for the treatment of malaria as a disease): chloroquine, mefloquine, doxycyline and atovaquone-proguanil. Primaquine is an alternative but is best left untouched as it is the only drug available to cure two of the four types of malaria.

Each of these drugs has a role to play in the drama of travelers going to malaria-risk zones. Figuring out which one to use and for which travelers, as well as for how long, deserves careful thought, and a travel health specialist really needs to be consulted for this. Please refer back to my article “The Malaria Medication Controversy” (Feb. ’05, pg. 98) for further details about the medications.

Dr. Spira is medical director of the Travel Medicine Center, 131 N. Robertson Blvd., Beverly Hills, CA 90211; visit www.healthytravel.com.