The plateau is about 45 miles long and separated from surrounding lowlands by high ridges; its primary inhabitants, the Makonde tribe, were farmers who often kept pigeons and goats around their thatched huts. After residents of one village on the eastern edge of the plateau were suddenly stricken with agonizing pain, the disease rapidly spread to dozens of others, and the Makonde started calling it "chikungunya," or "that which bends," in reference to its contorting effect on its victims.
British missionary doctors who worked in the area were startled. "The pain was frightening in its severity," wrote Dr. Marion Robinson, who worked at the nearby Lulindi Hospital and first noticed the epidemic, "completely immobilizing many patients and preventing sleep in the first few days of illness."
Over the next several decades, the disease tore through populations and then went away, only to show up years later somewhere new. Epidemics broke out in tropical, populous areas where the exclusively human-feeding Aedes aegypti was common: Bangkok in 1958, Calcutta in 1963, Vietnam in 1975, Malaysia in 1998.
But in 2005, an epidemic that had started in Kenya the year before appeared on the Indian Ocean island of La Reunion, where an earlier insecticide campaign had killed all the Aedes aegypti mosquitoes. Researchers discovered that the virus had mutated and was now being spread by another mosquito, Aedes albopictus -- a highly invasive species capable of living in much more temperate climates. Worse, the species can thrive both around humans and in nonpopulated areas like forests, making it virtually impossible to eradicate.
"The mosquito is everywhere," says Anna-Bella Failloux, a French researcher. "Using insecticide... you can kill Aedes aegypti, but you can't kill Aedes albopictus totally."
In 2007, a chikungunya-infected traveler from India landed in northern Italy, sparking roughly 200 cases within weeks -- the first chikungunya epidemic in Europe. The virus was again being transmitted by Aedes albopictus, and health officials braced for more epidemics to come.
"Since that time," says Failloux, "we were waiting for something to come to America."
The hemisphere's first outbreak was announced this past December 6 in Marigot, the capital of French-controlled Saint Martin. Two cases were confirmed, and 30 more were suspected. "Chikungunya is in the Pacific islands, in Asia, in India but never until now in the Caribbean islands," announced epidemiologist Marion Petit-Sinturel. "It's the first time we have had a located transmission here."
Within weeks, there were hundreds of cases on Saint Martin, and the disease had also spread to Martinique, Guadeloupe, Saint Barthelemy, French Guiana, and Dominica. By early March, there were 10,000 suspected cases on dozens of islands. By late April, there were more than 30,000. But the epidemic really exploded only once it reached the densely populated, less developed Dominican Republic, where chikungunya was first rumored to be spread through the air, or maybe as an act of terrorism, and where health officials struggled to make diagnoses. "For the first week, it was 'Oh my God, what is happening here?'" says Dr. Liddy Kiaty, who works in rural areas of the country. "It's not dengue; it's not malaria. What is this?"
At the end of May, nearly 40,000 cases had been reported in the D.R. By late July, the official tally was 260,000, although it was likely much more -- one doctors' organization reported that at least 1 million had visited hospitals with symptoms.
That same month, a well-known children's hospital in the capital, Dr. Robert Reid Cabral, announced that half its staff had been infected; in early August, the national women's volleyball team lost a game to Italy when three of its players were sick; and as the epidemic raged on, ordinary people everywhere -- young and old, rich and poor, urban and rural -- were suddenly seen limping and wincing their way through crowded streets, markets, and buses.
"You've seen the Thriller video by Michael Jackson? With the cadavers?" says 28-year-old Santo Domingo resident Massiel Pimentel. "That's how you walk with the pain, like the cadavers."
For years, Richard Wittig and his wife of 52 years, Judy, have been morning people. Richard is a licensed yacht captain and mostly retired realtor. He's 71 years old, with a friendly smile, combed white hair, and a cropped, Hemingway-white beard. Judy, also a veteran sailor, is a youthful-looking 72, with narrow features and straw-blond hair that falls to her shoulders. The Wittigs live in Pensacola, on a small residential island a few miles north of downtown. When they're home, they like to wake up around 6 or 6:30, drink coffee on their back porch, and watch the sun come up over the waterway that abuts their yard. Afterward, they like to go for long walks around the island with Bobbi, their 15-year-old Jack Russell terrier. "She's very active," Richard says. "She thinks she's 3."
On June 15, the Wittigs flew to San Juan, Puerto Rico, to visit their 47-year-old son, David, a chiropractor, who had moved there nine years ago after a divorce. The trip was planned as a relaxing three weeks in tropical paradise. "He was going to take us out to dinner every once in a while and just sit and talk and renew relationships, of course," Richard says.
David Wittig lives in a modest one-story, three-bedroom cement house in the city's tony Ocean Park neighborhood, just a few minutes from the sea. The house has a small courtyard with a nice patch of grass, and David keeps several chairs on the lawn -- the perfect place for visiting.
The first few days of the trip, Richard and Judy woke up early and drank coffee with their son in the courtyard; in the late afternoons, they lingered over cocktails in the same spot. But on June 19, a Thursday, Judy woke up in the morning unusually weak and stiff. Her son pulled a medical table out to the courtyard and tried to adjust Judy's spine and neck. But he had to stop when his mother was overcome with pain. "I could only stand it for about ten minutes," Judy says. "I started to scream."