||The History of Malaria
A Scourge Since Ancient Times
Malaria has been a scourge since ancient times. The early Egyptians wrote about it on papyrus, and the famous Greek physician Hippocrates described it in detail. It devastated the invaders of the Roman Empire. In ancient Rome, as in other temperate climates, the threat of malaria lurked in marshes and swamps. People blamed the unhealthiness in these areas on rot and decay that wafted out on the foul air, or, as the Italians were to say, "mal' aria" "bad air." In 1880, scientists discovered the real cause of malaria, the one-celled Plasmodium parasite, and 18 years later, they attributed the transmission of malaria to the Anopheles mosquito.
Historically, the United States is no stranger to the tragedy of malaria. The toll that this disease, commonly known as "fever and ague," took on early settlers is vividly depicted in the popular children's book "Little House on the Prairie" by Laura Ingalls Wilder. Historians believe that the incidence of malaria in this country peaked around 1875, but they estimate that by 1914, more than 600,000 new cases still were occurring every year. Malaria has been a significant factor in virtually all of the military campaigns involving the United States. In both the Vietnam War and World War II, more personnel time was lost due to malaria than to bullets.
The malaria parasite is transmitted to humans by mosquitoes belonging to the genus Anopheles. The larval stage of the Anopheles mosquito thrives in still waters, such as in swamps. The discovery by scientists that mosquitoes carried the disease unleashed a flurry of ambitious public health measures designed to stamp out malaria. These measures were targeted at both the larval and adult stages of the insect. In some areas, such as the Southern United States, draining swamps and changing the way land was used was somewhat successful in eliminating mosquitoes. The pace of the battle accelerated rapidly when the insecticide DDT and the drug chloroquine were introduced during World War II. DDT was remarkably effective and could be sprayed on the walls of houses where adult Anopheles mosquitoes alight and rest after feeding. Chloroquine has been a highly effective medicine for preventing and treating malaria.
In the mid-1950s, the World Health Organization (WHO) launched a massive worldwide campaign to eliminate malaria. At the beginning, the WHO program, which combined insecticide spraying and drug treatment, had many successes, some of which were spectacular. Malaria was conquered completely in areas inhabited by more than 600 million people, and sharply curbed in the homelands of 300 million others.
Difficulties soon developed, however. Some stumbling blocks were administrative, others financial. Even worse, nature had begun to intervene. More and more strains of Anopheles mosquitoes were developing resistance to DDT and other insecticides. Meanwhile, the Plasmodium parasite was becoming resistant to chloroquine, the mainstay of antimalarial drug treatment in humans. By the 1960s, malaria incidence was again on the rise. In some areas, disastrously so.
The incidence of malaria continues to grow. Researchers estimate that infection rates increased by 40 percent between 1970 and 1997 in sub-Saharan Africa. To cope with this dangerous resurgence, public health workers carefully select prevention methods best suited to a particular environment or area. In addition to medicines and insecticides, these include such standbys as draining swampy areas and filling them with dirt, and using window screens, mosquito netting, and insect repellents.
At the same time, scientists are intensively researching ways to develop better weapons against malaria, including:
- sophisticated techniques for tracking disease transmission worldwide;
- more effective ways of treating malaria;
- new ways, some quite ingenious, to control transmission of malaria by mosquitoes; and
- a vaccine for blocking its development and spread.
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Editor: Susan K. Boyer, RN
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