Now largely a tropical disease, malaria was once a global blight.
Aug 4, 2008, Vol. 13, No. 44 • By KEVIN R. KOSAR
The Making of a Tropical Disease
In 1881, the eminent Philadelphia publishing house Presley Blakiston began selling Joseph F. Edwards's Malaria: What It Means and How Avoided. In it, Edwards, an M.D. and author of other useful monographs, such as Constipation Plainly Treated and Relieved Without the Use of Drugs, complained that too many "incompetent physicians" attempting to hide their "want of penetration in diagnosis" had confused matters. The good doctor would set matters aright.
"I will define malaria for you," he promised, "and will furnish the definition in two words, BAD AIR." This blight on man's health was to be distinguished from another affliction, which he termed "intermittent fever," a mysterious affliction that caused dreadful spells of chills and fever. The cause of the latter was due to a "special, mysterious, unrecognized agent." Malaria's cause, however, was obvious--"Everything that has life, be it animal or vegetable, MUST DIE. Everything that dies MUST DECOMPOSE, and everything that decomposes MUST PRODUCE BAD AIR. . . . Therefore, it is self-evident that the surest way to avoid malaria is remove this matter from your presence while it is undergoing decomposition." Q.E.D.
Dr. Edwards, for sure, was not the first person to misconstrue malaria's nature. For at least two millennia scientists, naturalists, and others had gotten it wrong, blaming angry gods, unbalanced humors, and swamp gas. Indeed, as Edwards's example shows, even the best informed could not agree on the affliction's causes, or even its name. Malaria is the accepted nomenclature today, but in centuries past it has been called paludisme, swamp fever, and ague.
What all observers could agree on, though, was that malaria tended to occur in summer and autumn, and that it was--and still is--a god-awful pestilence. The afflicted may first feel minor symptoms, such as a headache and muscle pains. Then come horrendous chills, a skyrocketing fever, and pouring sweats. The spleen swells, anemia may set in, and the victim might fall comatose, in some cases with his limbs thrust out in frozen contortions. The fortunate evade death, but remain susceptible to reinfection throughout their lives.
Nobody was safe from it; malaria has killed millions, from the humblest field worker to eminent figures such as Alexander the Great, Pope Leo X, and Oliver Cromwell.
Discerning the causes of malaria required both technological advances and overcoming old ways of thinking about disease. Aided by microscopes and advances in medical science, researchers began to unravel the mystery of malaria. In 1880 French physician Charles Louis Alphonse Laveran discovered parasites (malaria plasmodium) in the blood of malaria victims. Around the fin de siècle, the British physician Ronald Ross found that the Anopheles mosquito could transmit malaria plasmodium from one bird to another, while the Italian researchers Giovanni Battista Grassi, Amico Bignami, and Giuseppe Bastianelli demonstrated that the same mosquito could spread this parasite from human to human.
Today, we have a pretty good grasp of the mechanics of malaria. The -Anopheles mosquito carries the plasmodium parasite, which it passes on to humans when it bites them. Plasmodium quickly travels through the circulatory system to the liver, where it takes up residence in liver cells, and multiplies. After a week or two, the liver cells burst, sending the disease into the bloodstream. Thereafter, the buggers penetrate blood cells and multiply until these cells burst and scatter still more pestilence in the circulatory system. (This recurrent cycle of bursting red blood cells accounts for the waves of fever that the victim experiences.)
The immune system and spleen work mightily to kill off the infection, and some victims recover. Too often, though, the victim's body cannot keep up with the exponential reproduction of the parasite. Red blood cells die en masse, the organs fail for want of oxygen, and the victim convulses and dies.
Armed with this knowledge, mankind has taken the battle to malaria. Draining swamps and oiling stagnant pools reduces the breeding grounds for Anopheles mosquitoes. Sleeping under mosquito nets can keep individuals from being bitten, and spraying DDT and malathion has killed off zillions of mosquitoes. Chloroquine, artemsinin, and other medications can disrupt the parasite's reproduction, thereby helping victims' bodies to defeat the pathogen. Isolating the afflicted in medical facilities prevents mosquitoes from biting them and spreading plasmodium to others.
Mankind has won stunning battles against malaria. Worldwide deaths from malaria went from around 3.5 million per year in the 1930s to perhaps 1.25 million today. Brazil reduced its annual malaria cases more than 90 percent, from three million in the 1940s to fewer than 700,000 at the end of the 20th century. Many countries, in North America, Europe, and much of Asia, are malaria-free. The occasional case pops up in these nations--as it did in Palm Beach in 2003--but the disease fails to take hold and spread.
Malaria, as the title of Randall Packard's short, dense volume indicates, has become a tropical disease. Whereas it once ravaged areas as far north as New York City (killing 450 people in the same year that Edwards published his wrongheaded book) and Archangel, Russia, malaria is now limited to Central America, Southeast Asia, and Africa.
These successes, combined with the ugly havoc that malaria continues to wreak, may have helped spur the recent calls for renewing the battle against malaria. The World Health Organization launched its "Roll Back Malaria" initiative in 1998, and this past year the Gates Foundation announced its intention to spend billions of dollars to eradicate malaria worldwide.
But should we expect past performance to be indicative of future returns? On this question, The Making of a Tropical Disease is especially pertinent. Packard, who directs the Institute for the History of Medicine at Johns Hopkins, has not produced a history of malaria per se. Regrettably, the reader will not find a chronological narrative that starts with the ancient Vedic and Chinese writings on malaria, or one that recounts in detail malaria epidemics and their effects on war, peace, and the rise and fall of nations.
Rather, Packard yanks the reader into an ongoing public health debate. He piles up case studies to argue that
The history of malaria has been driven by the interplay of social, biological, and environmental forces. The shifting alignment of these forces has largely determined the social and geographic distribution of the disease. . . . By contrast, efforts to control malaria . . . have been driven by a narrower vision of the disease and its causes that has privileged biological processes and focused on attacking anopheline mosquitoes and malaria parasites.
The result is a short book that reads long and tries the commitment of the general reader. That said, Packard's big point is a critical one. Malaria reduction and eradication have tended to be most successful in countries that were well on their way to being First World nation-states. The reasons for this are not hard to see. Modern nation-states have the wealth, power, and administrative competence to take the steps required to stop malaria. In the 1930s, the Tennessee Valley Authority used federal money and might to wipe out malaria: Marshes were drained, screens were installed in the windows of homes, medical facilities were established, DDT was sprayed, and the public was schooled on the causes and prevention of malaria. Malaria vanished in less than 20 years. (Around the same time, Italy similarly vanquished its infamously Anopheles-stricken Pontine Marshes.)
The results of this disparity are not hard to see, either. Today, if someone in, say, San Diego is suffering from chills and fever, he probably will head by car or ambulance to the nearest hospital where he'll immediately be diagnosed by trained medical personnel, given the correct drugs, kept in quarantine, and brought back to full health in short order.
In Zambia or Angola, today's malaria victim might be taken to a witch doctor who blames djinni and provides treatment that is useless at best. Or the afflicted might be carried for a few days to the nearest understaffed medical clinic, where he may be given watered-down medicines that kill the weakest plasmodia while leaving the strongest, most resistant, bacteria to propagate further. During his journey to and from the clinic, the victim may be bitten by more mosquitoes that will, in due course, spread the disease to others. Once home, the mosquito net provided by the clinic might end up being rigged up in a stream to catch fish rather than hung over his bed.
If that is not enough of an impediment to future progress in curbing malaria cases, there is also the matter of the plague itself. Initially, as Packard shows, mankind was able to score many fast victories against malaria because its attacks on the mosquito and the plasmodium were novel. With the passage of time, both organisms have responded to the assault, developing resistance to some medications and insecticides. There are at least 30 different malaria-carrying species of the Anopheles mosquito, each of which is evolving defenses.
Finally, there is the matter of climate and topography, key factors that Packard underplays. Temperature, humidity, and rainfall levels affect the ability of malaria to spread. Temperatures below 68 degrees Fahrenheit stunt the spread of the vicious falciparum species of plasmodium. Similarly, different parts of the earth are more favorable to the propagation of different species of Anopheles mosquitoes. Anopheles gambiae, a very efficient transmitter of malaria, breeds best in the environmental conditions found in the savannahs of sub-Saharan Africa. Not surprisingly, countries there are swarmed with Anopheles gambiae and deadly malaria cases. So, yes--malaria once clobbered Archangel's residents, but Zambia's inhabitants have suffered regularly for centuries.
All of which is to say that there is only so much man can do. First World efforts to economically and socially modernize Third World countries often fail. We cannot lower the temperature or reduce the rainfall in the tropical areas where malaria remains endemic. Regrettably, absent a miraculous medical breakthrough--the anti-plasmodium vaccine pursued by the Gates Foundation, and others--we can expect malaria to continue to afflict and kill people in tropical areas for the foreseeable future.
Kevin R. Kosar is a writer in Washington.