Mosquito-Borne Chikungunya Virus Invades America

Mosquito-Borne Chikungunya Virus Invades America

In mid-April, 39-year-old Belkys Jimenez came down with a high fever. She also developed a headache and then severe pain in her muscles and joints. Her feet and ankles became swollen, making walking painful. Jimenez had long battled hypertension, but this was clearly something new.

Over the next two weeks, her symptoms came and went. Several times, she visited a doctor in her hometown of Bajos de Haina, in the Dominican Republic. He provided acetaminophen for the pain and swelling and promptly dismissed her. The night of April 30, a Wednesday, Jimenez was feeling better. Before going to bed, she told her mother she would wake up early to go to the market.

But the following morning, Jimenez didn't get out of bed. Her worried mother entered the room and found her dark-skinned, soft-featured daughter cold to the touch. There was no pulse. Belkys was dead. "One day she was fine; the next day she was bad," Jimenez's mother told the Dominican television network Telenoticias. "She never got better from this."

Jimenez's hypertension had combined with a new, debilitating illness, and the complications had killed her, her mother said. The sudden death shook her neighborhood, but the rapid onset and severity of her illness surprised no one. Hundreds of residents of Bajos de Haina, a gritty, industrial town just south of Santo Domingo, were suffering from the same symptoms. They had fevers as high as 104, migraine-like headaches, and sometimes bright-red rashes covering their limbs. But worst was the joint pain -- typically so severe it made ordinary tasks like twisting doorknobs and tying shoelaces unbearable and forced even healthy young men to walk as if they had aged 50 years overnight.

"This is like a plague that the Bible talks about," one elderly woman said after Jimenez's death.

The cause was a mosquito-borne virus that, just months earlier, almost no one in the town knew: chikungunya. There is no cure or antidote, and while typically not fatal, the disease can leave victims in agonizing pain for months or years. In parts of Africa and Asia, it has been around for decades, but in the Dominican Republic -- and the rest of the Americas -- it was brand new. Though travelers had been diagnosed before, never had someone in the Western Hemisphere contracted the disease from local mosquitoes until last December 6, when the Pan American Health Organization (PAHO) confirmed two cases in the tiny Caribbean nation of Saint Martin.

The region soon faced a pandemic. By midsummer, when the world's attention was suddenly consumed by another African viral epidemic -- Ebola -- chikungunya had infected hundreds of thousands in the Caribbean and was gradually creeping into the United States. People from Maine to California contracted it after traveling to affected countries, and this past July 17, public health officials announced that two Florida residents had been infected by local mosquitoes -- marking the first time chikungunya had been acquired in the United States. The door was open to thousands of new American cases.

"It's a new disease," says Dr. Scott Weaver, a virologist at the University of Texas Medical Branch. "I think it's one of the most serious threats from a mosquito-borne disease in the U.S. in many years."


Just after 8 a.m. on a bright Tuesday in early August, Yasser Compagines walked through a middle-class neighborhood in Hialeah, his eyes darting from one neatly fenced-in driveway to the next. Compagines, a well-built man with a shaved head and a quick stride, wore a light-blue polo tucked into dark khakis, a black wristwatch, and sunglasses hanging around his neck. On the back of his shirt, in huge capital letters, were the words "Miami-Dade Mosquito Inspector." A neighborhood resident had called to complain, and Compagines had come to locate and kill.

The inspector walked past two houses, then spotted a broad, gray cement flowerpot, maybe two feet tall and engraved with an intricate, curved-line pattern. He approached the pot and stopped, then doubled at the waist so his bald head was just inches from the container's top. "This is fresh water from the rain," he announced. It was not a mosquito breeding ground.

But the pot was resting on a cement base that was a few inches tall and saucer-shaped, like a large, upside-down Frisbee. Compagines crouched to the ground, his face creasing from the glare. This time the water, about two inches deep, was green-tinted, with dark spots of algae and dirt. Swimming in it were dozens of black, wriggly, pinhead-sized creatures -- larvae of the Aedes aegypti mosquito. "These are ready to pop," Compagines said.

Aedes aegypti were first identified three centuries ago by a Swedish entomologist in Asia Minor. The speckled black, white, and brown mosquito is found in tropical locations around the globe and has long been identified with diseases like yellow and dengue fevers. But about 60 years ago, scientists discovered it was also transmitting another, potentially even more devastating virus: chikungunya . Although it has likely been present in parts of Asia and Africa for millennia, this virus was identified by scientists only in 1953, after thousands of villagers living on the Makonde Plateau, in present-day Tanzania, suddenly became crippled and bedridden.

 

Yasser Compagines, a county mosquito inspector, examines the stagnant water inside the base of a flower pot for larvae.
Yasser Compagines, a county mosquito inspector, examines the stagnant water inside the base of a flower pot for larvae.
Photo by Trevor Bach

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.

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.

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."

 

The Aedes aegypti mosquito is common throughout South Florida and is responsible for spreading the ongoing epidemic.
The Aedes aegypti mosquito is common throughout South Florida and is responsible for spreading the ongoing epidemic.
Shutterstock

Soon Judy was running a high fever and feeling nauseous. For the next four days, she barely left the bed. Her ankles were so swollen that it hurt to make contact with the ground, and when she did stand, she often felt as if she were going to lose her balance and fall. But within a week, by the 26th, Judy was feeling slightly better. Her pain was still severe, and she had developed a rash, but she could at least get out of bed and limp around the house.

Then Richard fell ill. Like Judy, he developed a fever in the late afternoon, climbed into bed, and within hours was writhing in pain. His case was much worse. It felt as if someone were squeezing his back, hands, feet, and knees with pliers, or maybe beating on him with a hammer. Richard and his wife were no strangers to tropical diseases, having both previously contracted typhoid fever and amoebic dysentery as they transported boats through the Caribbean. "But this made typhoid fever feel like a light cold," Richard says.

He took Benadryl every four hours -- "You don't notice the pain as much when you're asleep" -- but for the next two weeks, he barely stood up. It hurt too much, and he was too weak. "I had to have somebody help me get out of bed."

Even to walk to the bathroom, Richard was forced to yell for his wife, who herself would then limp over and support him as he leaned against the walls for support. She also had to open the door -- Richard's hands and wrists hurt too much to turn the knob himself.

"Before, the [doctors] would always ask you what kind of pain you're in, from zero to ten," says Richard. "Ten is kill me; I don't want to live... I guess I was up pretty high, about like a six."

Still in agony, the Wittigs, who had contracted both chikungunya and dengue fever, managed to fly back to Florida on June 7. But they still couldn't drive a car, go for a walk with the dog, or enjoy their morning coffee. Richard still couldn't turn a doorknob. "I thought it was going to do us in," says Judy. "You feel so debilitated... like you're never going to get better."


Ten days after the Wittigs arrived home, Florida health officials made an announcement: The country's first two locally acquired cases of chikungunya had been confirmed. The victims were a 41-year-old woman in Miami-Dade County and a 50-year-old man in Palm Beach County. "At this time, there is no broad risk to the health of the public," Dr. Celeste Philip, a Florida deputy secretary for health, said in a telephone news conference from Tallahassee.

Monica Abrams, a 56-year-old small-business owner in St. Lucie County, saw the announcement on the news. That same afternoon, she walked into a local clinic, her lobster-red legs showing below her shorts, and asked for a blood test. "I think I have chikungunya," she says.

She didn't know that a highly efficient virus had been injected into her and was multiplying, traveling through her bloodstream to her liver, muscles, and brain.

Abrams, who asked that her real name and exact location not be used because of privacy concerns, is gregarious and animated, with short ginger hair and a Long Island accent. Less than two weeks before, her summer had been going well. On July 4, she had watched a fireworks show while sitting outside. The next day, a Saturday, she had helped a friend paint the exterior of her house. On Sunday, she had gone for a leisurely ride with her husband on the back of his Harley Road King. She doesn't remember being bitten. She didn't feel a mosquito land on her skin or suck her blood. She didn't know that a highly efficient virus had been injected into her and was multiplying rapidly, traveling through her bloodstream to her liver, muscles, and brain. But a week or so later, Abrams realized something was very wrong.

On July 11, she woke up around 7 a.m., as she always does. When she rolled out of bed and stood, she felt a sharp pain in her left hip. For years, she's had a bad back, and she assumed she must have thrown it out during the night. A bit later in the kitchen, she flipped on the local TV news, made a cup of coffee, and took a seat on a barstool.

A few minutes later, she tried to stand, but when her right foot touched the ground, she felt a shot of searing pain. "It was like I had dislodged a bone," she says. Within a few hours, her right wrist and thumb also ached. She stubbornly tried to walk it off, still thinking she just needed to loosen up her back, but it only got worse. By evening, her right foot and ankle had swollen, and her wrist was sensitive enough that even a faint touch made her wince. Still, Abrams convinced herself she'd be better by morning. "Tomorrow's another day," she thought to herself as she collapsed into bed. "I'll be OK."

The next day was worse. It hurt to stand, walk, or move her arms. The following day was the same. But then the pain disappeared. "Halfway through Monday, it was like a light switch. It was gone."

That afternoon Abrams' 1-year-old granddaughter came over, and the proud grandma bobbed up and down in the pool with the baby, the cool water relaxing her body and lifting her spirits. Then she got out, and Paul, her husband, noticed that her entire body and face were bright red. "When did you get time to get a sunburn?" he joked.

The next few days, the pain was bearable, but the rash remained. For a few days, Monica Abrams wavered about getting her blood tested. She had seen reports in the news about travelers returning with chikungunya, and she knew her joint pain and rash seemed to fit the disease's symptoms. But it still seemed absurd to think she could have contracted it around her suburban home. Then came the announcement of the first locally acquired cases, and Abrams knew she had to go.

"You feel silly, because you know there's only two other people that locally contracted this, none in St. Lucie County. Now you're going to be this crazy 56-year-old lady that thinks [she has] every symptom they put on the news."

 

Dr. Scott Weaver, a virologist at the University of Texas Medical Branch, has been working on a chikungunya vaccine for more than a decade.
Dr. Scott Weaver, a virologist at the University of Texas Medical Branch, has been working on a chikungunya vaccine for more than a decade.
Photo by Daniel Kramer

After being tested, Abrams waited. The clinic told her the county health department would be in touch within a couple of days. Early the next week, someone called to say Abrams' blood had tested negative for dengue fever. Then a second call disclosed she had tested negative for Lyme disease. For several more days, there was no word. The wait became excruciating. "So I started calling every day -- 'What about the chikungunya?'"

Finally, on July 26, Abrams was told she had tested positive, and on July 30, after the sample had been sent to another lab for confirmation, the St. Lucie County Health Department announced the results. Abrams had officially become the third locally acquired chikungunya case in the United States.

By then, the pain had come back, and it was worse than ever. Abrams' fingers and wrists hurt too much to pick up a plate. Her back throbbed to the point where she dreaded the thought of even turning over in bed. Her knees and feet hurt so much that she sometimes lay flat for hours just to avoid touching the ground. "The only way I can describe it to you is if you could take your feet, have somebody crush all the bones in them, and then ask you to walk constantly."

The pain had become overwhelming. Consuming. Surreal.

"I thought I was going to die," she says. "I was terrified it was never going to go away."


Dr. Scott Weaver is struck by chikungunya's beauty. A virologist at the University of Texas Medical Branch in Galveston, he has spent more time with it than anyone in America. He has stared through a microscope for hours at its millions of intricate, prickly edges, mesmerized by its bright colors.

For more than a decade, inside a Biosafety Level 4 lab 50 miles from Houston -- the same place where scientists pore over Ebola -- Weaver has been dedicated to creating a chikungunya vaccine. "I've spent my entire career working on this virus," he says. "Someone should benefit."

"He has stared through a microscope for hours at its millions of intricate, prickly edges, mesmerized by its bright colors."

Weaver is tall and lanky, with graying hair and a thick salt-and-pepper beard that extends high on his cheekbones. He often wears plaid shirts, even in the lab, which gives him the look of a 1970s computer geek or a misplaced lumberjack. Weaver, who is now in his 50s, first became fascinated by mosquitoes and the diseases they spread more than 30 years ago, when he cataloged insects around the swamps of his native Maryland during the summer after his freshman year of college.

He has tracked chikungunya through Africa, Southeast Asia, and, recently, the Caribbean, though he typically spends most of his time in his spacious office in Galveston, surrounded by heavy wooden furniture and various mosquito paraphernalia, including a mosquito hand puppet.

When he first started at the university in the 1990s, Weaver worked mostly with chikungunya epidemiological data, tracing the origins and cycle of chikungunya and other alphaviruses. But then came September 11, 2001. After the terror attacks, the National Institutes of Health (NIH) in Bethesda, Maryland, suddenly began pouring millions into research funds and biodefense, including for emerging infectious diseases like chikungunya.

"We developed our first vaccine within a matter of months," says the researcher. Weaver's team had used a living sample of the virus, just as doctors did for the polio and other vaccines. But live vaccines require an incredibly delicate balancing act -- they must be strong enough to be effective at inducing antibodies yet weak enough to not make humans sick or to spread the virus to other mosquitoes if the vaccine recipient is bitten.

It finished creating the first version of the vaccine in 2007, but Weaver's team was concerned this vaccine could be transmitted to mosquitoes from its recipients. The researchers had to start again. In 2011, they developed another version that has proven effective and safe in preclinical trials. But Weaver can't move on to clinical trials -- tests on real people -- because large pharmaceutical companies aren't yet willing to risk the millions of dollars that would likely be needed, he says. And human trials, of course, are critical for approval by the Food and Drug Administration. "The FDA is extremely conservative," he says. "And in this country, a lot of these infectious diseases aren't causing enough life-threatening infections to make the public worry whether there's a product available or why it takes years to get one approved."

The NIH is also developing a chikun-gunya vaccine, as are numerous other research centers. And last month, the institutes reported a successful human trial: Twenty-five volunteers who received the vaccine developed an effective antibody response. The NIH vaccine isn't live, which means it's considered safer, but it's also less efficient and has to be administered via three shots over the course of a month. "If you want to stop an epidemic, you can't take a month to vaccinate," Weaver says. "You can't even get people to come back for all of their doses of the vaccine most of the time."

Moreover, the NIH vaccine still needs a second trial, and after losing its previous pharmaceutical support, the institutes are searching for funding. Merck, the New Jersey-based company that had supported the project, pulled out after deciding against a large-scale trial it was considering in India. "The take-home message was no one knew how much disease they had in India, so there was no way of knowing how many they'd have to vaccinate to show efficacy," Weaver says. "And to get that information, they'd have to pay for it." (Researchers from the NIH declined to speak with New Times.)

Weaver's vaccine technically has a backer, Tokyo-based Takeda Pharmaceutical, but so far the company hasn't invested much, despite the vaccine's promise. "Now the vaccine is less of a scientific problem and more of a financial and logistical problem," Weaver says.

 

Chikungunya's symptoms include foot swelling and a bright-red rash, along with fever, headache, and excruciating joint pain that can last years.
Chikungunya's symptoms include foot swelling and a bright-red rash, along with fever, headache, and excruciating joint pain that can last years.
Wikimedia Commons/Nsaa

With no vaccine likely to be available for years, the chikungunya epidemic in the Americas will continue claiming victims. As of September 12, the PAHO reported an official number of more than 700,000 cases in the Caribbean, Central America, and Venezuela, including 467,000 in the Dominican Republic, 77,000 in Guadeloupe, and 64,000 in Haiti. But the actual number could be several times higher, because many people who contract the disease never visit a hospital. One hundred thirteen people who contracted the disease, most of whom suffered from other ailments as well, have been reported dead.

In the United States, as of September 16, the Centers for Disease Control reported a total of 1,043 confirmed foreign-acquired cases in 45 states, including 195 in Florida, 252 in New York, and 26 in Texas.

The U.S. has now confirmed ten locally acquired cases, meaning people who contracted the disease from local mosquitoes. On July 30, the same day Monica Abrams' illness was reported, a second locally acquired case was confirmed in Palm Beach County, prompting the county health department, for the first time, to issue a chikungunya alert. Three weeks later, on August 20, Palm Beach confirmed two more locally acquired cases. "Our best advice to the community is to be aware that there's another mosquito-borne disease that they could be affected by," says Tim O'Connor, the health department spokesman, who emphasizes residents should use repellent and drain mosquito breeding grounds such as flowerpots and birdbaths. "It's the only defense we have."

So far, the local outbreak has been spread only by Aedes aegypti, the tropical mosquito, and all the locally acquired cases have occurred in Florida, one of the few places in the U.S. warm enough for the species to live. But Aedes albopictus lives throughout most of the United States. The virus could easily mutate, as it did before, to be spread by that species as well, which could spur locally acquired cases around the country.

In the past, Aedes albopictus has actually spread the virus even more efficiently than Aedes aegypti. The La Reunion outbreak had been so explosive, said Failloux, the French researcher, in part because the Aedes albopictus mosquitoes themselves became infectious exceptionally quickly. After a mosquito ingested an infected human's blood, the mutated virus traveled from its stomach to its saliva -- through which the mosquito can then infect another human -- within just two days. "That's very, very short," Failloux said.


On a Monday afternoon in late August, Monica Abrams is perched in her cozy office in front of a computer with rotating screensaver pictures of her bubbly granddaughter. Six weeks after she fell ill, Abrams still can't move her arms and hands enough to cook, and she's too weak to lift even small boxes. She struggles to walk. "Every day is a little better," she says. "Yesterday was a setback."

For more than half an hour, Abrams sits still in her office chair answering a reporter's questions. Then, wanting to fetch a glass of water, she unfolds herself slowly, as if in a back brace, and steels herself. The searing agony that for weeks has come every time she places her foot on the ground is mostly gone now, but some days the pain is still intense. She also feels a near-constant, numbing sensation in her wrists, hands, feet, and ankles. Abrams slowly lowers her feet to the carpet. She pushes herself up, waits a second, and begins to shuffle forward, dragging her left leg behind the right. A few minutes later she returns, holding a full mug. She smiles.

Abrams is in good spirits, but throughout the summer, she's often struggled with depression. Sometimes she doubts the pain will ever go away. Getting bitten by an infected mosquito, she says, was about as likely as hitting a lottery ticket. By now, she's mostly come to terms with her exceptionally bad luck, she says, but one thing still confounds her: In the time frame during which she contracted the virus, she hadn't traveled outside St. Lucie County. Someone else in the area must have had it before her, and it seemed near-impossible that no one else had been bitten by an infected mosquito around the same time she was. "I just find it surprising," she says, "that there isn't somebody else."

Four days later, on August 29, Clint Sperber, a deputy administrator with the Florida Department of Health, made an announcement: The nation's seventh locally acquired chikungunya infection had been confirmed -- a second victim in St. Lucie County.




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