plied inappropriately. The situation in many African nations is particularly dismal, exacerbated by a crumbling health infrastructure that has made the implementation of any disease control program difficult.

Malaria cases among tourists, business travelers, military personnel, and migrant workers in malarious areas have been increasing steadily in the last several years, posing new concerns that the disease will be introduced to currently nonmalarious areas. Recent epidemics have claimed tens of thousands of lives in Africa, and there is an increasing realization that malaria is a major impediment to socioeconomic development in many countries. Unless practical, cost-effective strategies can be developed and successfully implemented, malaria will continue to exact a heavy toll on human life and health around the world.

Although often considered a single disease, malaria is more accurately viewed as many diseases, each shaped by subtle interactions of biologic, ecologic, social, and economic factors. The species of parasite, the behavior of the mosquito host, the individual's immune status, the climate, human activities, and access to health services all play important roles in determining the intensity of disease transmission, who will become infected, who will get sick, and who will die.

Gem miners along the Thailand-Cambodia border, American tourists on a wildlife safari in East Africa, villagers living on the central highlands in Madagascar, residents of San Diego County, California, a young pregnant woman in Malawi, Swiss citizens living near Geneva International Airport, children in Africa south of the Sahara, and a U.S. State Department secretary in Tanzania seem to have little in common, yet they are all at risk of contracting malaria. Because of the disease's variable presentations, each will be affected differently, as illustrated below.

  • For the hundreds of thousands of Thai seasonal agricultural workers who travel deep into the forest along the Thailand-Cambodia border to mine for gems, malaria is the cost of doing business. These young men are exposed to aggressive forest mosquitoes, and within two to three weeks after arriving, almost every miner will get malaria. Many gem miners seek medications to prevent and self-treat mild cases of the disease. But because malaria in this part of the world is resistant to most antimalarial drugs, the few effective drugs are reserved for the treatment of confirmed cases of malaria. To complicate matters, there are no health services in the forest to treat patients, and the health clinics in Thailand are overburdened by the high demand for treating those with severe malaria, most of whom are returning gem miners. A similar scenario involving over 400,000 people exists among gold miners in Rondonia, Brazil.

  • Each year, over seven million U.S. citizens visit parts of the world



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