Katy Clark

It's one of the leading causes of sickness and death in the world; as many as half a billion people fall ill from it every year, and more than a million of them -- mostly children -- die. The disease is malaria. It affects largely the world's poor, and because of that, scientists say, there's been little money available to fight this major disease. But now wealthy foundations, companies, and governments are making malaria a priority. President Bush has pledged more than a billion dollars to the cause. This week on The World we'll examine the renewed fight against malaria. We begin our series today with a bit of history. It's the tale of one country that defeated malaria more than half a century ago. Here's The World's Katy Clark.

Listen to the report

Historian Margaret Humphreys teaches at Duke University in Durham, North Carolina. She studies the history of disease. Humphreys says most Americans today don't realize that just a few generations ago, malaria was a big problem in the United States.

Humphreys: "When my grandmother was told she was moving to East Tennessee from Minnesota in 1938, she was afraid for her children that they were going to a place where they would get sick. And I ask my students at Duke, 'Did any of you consider whether leaving Chicago or New Jersey was going to take you to a place that was going to make you sick?' And they all look at me with bewilderment. It used to be a marker of the South."

Early southern home

English colonists brought malaria to Jamestown, Virginia, in 1607. By fleeing the Old World for the New, they unwittingly carried the disease with them. It then spread across the continent. By the 1800's, malaria could be found as far north as the Dakotas, south to Louisiana, and along the Eastern Seaboard from Florida to Massachusetts. During the Civil War, malaria killed thousands of soldiers, both in the Union and Confederate armies.

Malaria was especially prevalent in the Mississippi Valley. That made a deep impression on writer Charles Dickens during his travels there. Margaret Humphreys cites the experiences of the title character in Dickens' novel "The Life and Adventures of Martin Chuzzlewit."

Humphreys: "Chuzzlewit ends up in America. He's sort of condemned to hell in the structure of the book, which ends up being Cairo, Illinois. And he comes to this town, which he's been sold property in, and everybody there is sick. One of the father figures in the story has just buried one child from malaria and his other son is sick. It is just probably the most desolate environment you could probably imagine and not exactly what we'd associate with Illinois, which at the time was a booming frontier state."

For thousands of years, no one knew what malaria was or how it spread. The Romans thought the disease was carried by fumes emanating from swamps.

The name "malaria" comes from the Italian for "bad air."

It wasn't until the late 1890's that scientists learned that a parasite causes the disease and that certain mosquitoes transmit the parasite from person to person.

Four types of malaria parasites infect humans. Each looks slightly different when viewed under a microscope.

"You can see it's a purplish thing. It's not a very pretty parasite. It's falciparum."

Bill Collins is a malaria expert with the U.S. Centers for Disease Control and Prevention in Atlanta. The CDC was founded in 1946 specifically to help control malaria. Today, the CDC has one of the few labs in the world that keeps mosquitoes infected with all four strains of human malaria.

The strains not only look different, they act differently, too.

Collins explains that the falciparum parasite can kill you if left untreated. Vivax just makes you wish you were dead. That was the case, he says, for many U.S. soldiers who fought in the Spanish-American war in the late 1890's.

Collins: "A lot of the soldiers from the North went down and fought on the islands - in Cuba and that - and they got malaria. And they got a lot of malaria, so bad they almost revolted."

By the turn of the 20th century, malaria had begun to disappear from many parts of the United States. CDC entomologist Bob Wirtz says as America became more industrialized, living conditions improved.

Collins: "Malaria's really a disease of poverty. When you develop the infrastructure and the capabilities, people move into screened houses or air conditioning, clean up the environment, get rid of the breeding sites, then mosquito populations decrease and transmission is reduced."

But malaria continued to plague the Southeastern United States long after the disease vanished elsewhere. Mosquitoes were simply more abundant in the South. And the deep poverty there meant share croppers' cabins didn't evolve into the tight, mosquito-proof houses that were being built in other parts of the country.

So in the late 1940's, the U.S. government launched a malaria eradication program focused on the South. National, state, and local officials drained swamps and wiped out other mosquito breeding grounds. They also sprayed the insecticide DDT inside every southern home.

Historian Margaret Humphreys says most people welcomed the spraying of DDT.

Humphreys: "It was hyped in newspapers and popular magazines. This was the atomic bomb of insect warfare. And the DDT didn't just kill mosquitoes. It killed fleas and bed bugs and cock roaches, and people loved it."

DDT advertisement in Time Magazine 1947

Humphreys says people who may have had some initial reservations about the campaign were won over after hearing their neighbors sing the praises of DDT. And by 1949 -- just a few years after the eradication campaign started -- the United States was declared malaria-free. Malaria still crops up here from time to time, but these sporadic cases are the result of travelers bringing the disease back from overseas.

Following the defeat of malaria in the United States, the World Health Organization launched an eradication effort of its own in the 1950's. The goal was to wipe out the disease across the globe through spraying, surveillance, and the distribution of anti-malarial drugs. The plan worked well enough in places with more temperate climates, but problems developed in other parts of the world. Mosquitoes developed resistance to DDT, and little effort was put into fighting malaria in sub-Saharan Africa.

Bill Collins says it became too impractical to replicate the U.S. model in the developing world.

Collins: "DDT is sprayed on walls. Most of the houses in Africa did not have walls. Where are you going to spray? You had no organization to have spray workers go out into the areas to do it. There was just no way to set up a program in these countries to hire spray workers to actually carry out the program."

And in the late 1960's, the WHO conceded defeat. Some have argued that the eradication of malaria from the United States and Europe actually hurt efforts in the developing world, because rich nations no longer considered malaria a problem.

But that's starting to change.

International aid organizations are stepping up distribution of anti-malarial drugs and bed nets to protect against mosquitoes. Scientists worldwide are also working to develop a malaria vaccine.

They hope to help the hundreds of millions of people who still fall ill from malaria each year, more than half a century after the disease became history in the United States.

For The World, this is Katy Clark.