Breakbone Fever Attacks Enchanted Island: Battling the 2010 Dengue Epidemic in Puerto Rico

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Mosquito biting human 

by Tyler M. Sharp, PhD

Paradise Has Its Risks
Given the choice I prefer my bones to remain unbroken. For that reason I began to worry when I found out that the disease I would be studying for the next two years in Puerto Rico was also referred to as “breakbone fever.”

In April of 2010, I accepted an assignment to study dengue fever as an Epidemic Intelligence Service Officer at the CDC Dengue Branch in San Juan, Puerto Rico.  While I was thrilled to be moving to “The Island of Enchantment,” reality began to sink in when I realized that I was running head first into an ongoing epidemic of a painful and deadly disease.

Earlier that year, CDC had issued an update on the status of dengue in the Caribbean, warning of impending epidemics.  From my time in graduate school I knew that the four viruses that cause dengue are transmitted by mosquitoes, but I didn’t know much about the illness itself. When I started reading up on dengue, I found out that the name “breakbone fever” comes from the intense bone and joint pain that accompanies the disease. Patients with severe forms of dengue can experience hemorrhage, shock, and even death.  I also discovered that the World Health Organization estimates that there are about 100 million cases of dengue each year, including 500,000 hospitalizations and more than 25,000 deaths.  This was serious business!  What had I gotten myself into?!

Getting to Know the Enemy
On my first day on the island the Dengue Branch had arranged for me to meet with a realtor.  We spent the day looking at apartments throughout San Juan and eventually I found a nice spot in Punta Las Marias.  Afterwards, my realtor invited me to her house to sign papers and celebrate over dinner with her husband.  I immediately accepted, drooling at the chance for a home-cooked Puerto Rican meal: chuletas de puerco (pork chops), chillo ala parilla (grilled red snapper), arroz con habichuelas (rice and beans), and amarillos (fried sweet plantains).  A full belly and a cubalibre (rum and coke with a lime) later, I was a happy guy!

Sunset overlooking San Juan, Puerto RicoAfter dinner, we retired to the back porch where the first thing I noticed was the mosquitoes.  They were everywhere! Clouds of them clustered in the corners and they seemed to follow my realtor’s dog around like a permanent shadow. Soon enough I was swatting at my own cloud of blood sucking pests.

As we were watching the sun slowly slip over the horizon, my supervisor from the Dengue Branch called to check in on me.

Hi, Tyler! I’m so glad that you’re on the island!  Look, Puerto Rico is in the middle of a really bad dengue epidemic right now, so try not to go anywhere where there are mosquitoes, OK!?  AVOID MOSQUITO BITES!”
Slap, splat, smoosh! Went the mosquitoes as I tried to stop them from gorging on my delicious gringo blood.  “‘Mosquitoes,’ you say..?”

Reality Sets In
The gravity of the epidemic soon came into sharp focus.  My very first day on the job one of my co-workers informed me that Puerto Rico’s Secretary of Health was going to have a meeting that night to discuss the dengue epidemic.  “It’ll be a great introduction to public health in action in Puerto Rico,” he said, encouraging me to attend.  I eagerly agreed.

Once the meeting got going, it was clear that the Secretary was concerned about the number of reported dengue cases which continued to rise, as did the number of deaths.  From the Secretary’s point of view, even one death from dengue was too many.
Attendees for Train the Trainer sit watching a power point presentation

The meeting focused on efforts to heighten awareness and clinical management among physicians across the island.  In response to previous dengue epidemics in Puerto Rico, the Dengue Branch and the Puerto Rico Department of Health (PRDH) had designed a train-the-trainer course on the clinical management of dengue. In this course, Dengue Branch staff educated local physicians in Puerto Rico on how to clinically diagnose and treat patients with dengue; these “Master Trainers” then relayed their training to other local physicians.  The course included instruction on how to identify and respond to warning signs for severe disease (such as abdominal pain and persistent vomiting) and the “critical phase” of illness (24–48 hours after fever has broken) when patients should be closely monitored.  The Secretary announced at that meeting that all physicians in Puerto Rico who see patients with dengue would have to attend the course or risk losing their license to practice medicine. 

Various ideas for containing the spread of disease were discussed during the meeting. The most interesting by far came from an older gentleman who described a traditional Puerto Rican method of keeping mosquitoes out of the house: 

“When I was growing up, we had a way to keep the mosquitoes away that never failed.  What you have to do is take a bottle of tequila and pour it ALL over the walls!  After that, you’ll never see another mosquito land on that wall!” 

I will confess that I have not experimentally tested this approach to mosquito control; however, I can think of several more interesting and efficacious uses for a good bottle of tequila.

Arming the Resistance
Man spraying mosquito repellant on his armsBecause there is still no vaccine for dengue (although several are in clinical trial), methods of preventing dengue focus on employing strategies to avoid mosquito bites.  The good news is that use of mosquito repellent, wearing long-sleeved shirts and pants, and staying in air conditioned or screened-in housing can all reduce the risk of getting dengue. 

The bad news is that the dengue mosquito, Aedes aegypti, has quite literally evolved alongside humans.  The mosquito has learned to cohabitate with humans, thriving in manmade creations that contain stagnant water such as discarded tires, septic tanks, and neglected flower pots.  Once hatched, the mosquitoes take up residence in and around human dwellings, especially in closets and under beds.  So not only should you avoid mosquitoes while you’re out and about, you should especially be vigilant while at home and while visiting other people’s homes. Once infected with dengue virus, the female mosquito remains infected for her lifetime (~ 1 month) and passes the virus to humans when she takes a blood meal.  

Men loading tires into a truckInstead of sitting idly by and counting cases as they came in, the Dengue Branch and PRDH focused on raising the public’s awareness of the on-going epidemic and bolstering PRDH staff responsible for mosquito control.  Public health teams from across the island worked together to organize public health messaging campaigns.  People were instructed to turn over or cover water storage containers and recycle old tires to eliminate mosquito breeding sites, kill adult mosquitoes in their homes, use mosquito repellent, and seek medical care if they developed acute febrile illness with dengue-like symptoms.  In addition, more than 8,000 clinicians attended the course on the clinical management of dengue.  

The Fallout
By the time the dengue epidemic was officially over in December, nearly 25,000 cases were reported and 38 people were confirmed to have died from dengue.  To put that in perspective, at least 1 in 100,000 people living in Puerto Rico in 2010 died from dengue, which is only slightly less than the number of annual deaths due to influenza in the United States.  All in all, it was the worst dengue epidemic Puerto Rico had seen since monitoring began in 1969.
One thing that still amazes me is the response that PRDH and the Dengue Branch had to the epidemic, for which they ultimately received awards for excellence in both Partnering and Emergency Response.  This was a testament to the herculean task that faced public health in Puerto Rico in 2010 following the dengue epidemic. 

As a novice to public health and CDC, the dengue epidemic allowed me to experience firsthand CDC’s mission of supporting local health departments to keep people healthy and safe.  As a result of that mission, I and countless others never got dengue.  We therefore owe both PRDH and CDC a debt of thanks for keeping our bones unbroken, as I prefer them to be.

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19 comments on “Breakbone Fever Attacks Enchanted Island: Battling the 2010 Dengue Epidemic in Puerto Rico”

Comments listed below are posted by individuals not associated with CDC, unless otherwise stated. These comments do not represent the official views of CDC, and CDC does not guarantee that any information posted by individuals on this site is correct, and disclaims any liability for any loss or damage resulting from reliance on any such information. Read more about our comment policy ».

    How likely is it that this disease can be carried into other countries through persons traveling? Can the mosquitoes survive on an airplane?

    There is also a rise of cases of “breakbone fever”, but more commonly known here in the Philippines as “Dengue Hemorrhagic Fever or DHF”. This is a classical example of a very deadly disease that is highly PREVENTABLE!!! I for one has been a victim of this disease but through early diagnosis and proper intervention I was able to fight for it. I agree that the vector, Aedes aegypti, can be easily eliminated through cleaning your environment especially the stagnant water that can either be sitting in unused pots or your flower vases inside your house. Vigilance is also a key. Report early signs of the disease to your health care provider.

    I had Dengue TWICE in the 14 years I lived in Jamaica. It is truly a terrible disease. The second time I had it the joint pain never completely went away – 4 years later I still have it. The really bad thing about the disease in JA. is that the government doesn’t seem to want the tourists to know about it. I know a couple of people who went home, then came down with it and their U.S. doctors had a very hard time diagnosing it. But JA is like anywhere in the tropics – mosquitoes are EVERYWHERE. Serious ting dat!

    Dengue is extremely dangerous. I feel that the impact is often more severe in developing countries where the health care system is less stable! But I’m glad that there are strategies put in place to control this epidemic.

    I live in Conway SC and there is a mosquitoes problem in our area. I live near a bay that has standing water. DHEC won’t let us fill it in because its consider wetland. I can’t even walk outside without getting bitten by a mosquitoes. Just wondering if there have been any known causes of Dengue in SC?

    In Vietnam my homeland. Mosquito thrives. Every year many people die or disease related to insects. Alarming fact that we need, but good planning and methods to reverse the epidemic.

    Great job done. Is the disease limited to conditions as ideal as those in Puerto Rico or ca n also be noticed in another country?

    Thanks for your question, Michele. There is extensive evidence of travelers to regions with endemic dengue bringing the virus back with them when they return home. In example of this, we recently reported a cluster of dengue cases in a group of US missionaries traveling to Haiti , and CDC regularly summarizes dengue cases in US travelers . Moreover, dengue virus imported by travelers is thought to have been responsible for recent outbreaks of dengue in Florida, Hawaii and south Texas, all of which have the dengue mosquito, so local outbreaks of dengue from infected travelers is a real concern.

    To address your second question, mosquitoes can and do get transported by airplanes (more info here). However, it seems to be rare that these imported mosquitoes are able to survive the journey, escape the airport, and then set up new breeding sites. So, although it may occur in rare instances, it is unlikely that these imported mosquitoes appreciably contribute to the burden of disease due to illnesses like dengue.

    Hi Valeria,

    To my knowledge, there have never been any reported cases of dengue that were acquired in South Carolina, although there was one imported case (meaning the individual was infected while traveling to a country where dengue is endemic). You can find more information on dengue in South Carolina and the rest of the United States here.

    Hi Serena,
    Dengue is actually endemic throughout the tropics of the world, and ~40% of the world’s population lives in an area where dengue is endemic. More info on the distribution of dengue worldwide can be found here

    I live in the Dominican Repulic and several of my friends have contracted this fever. It’s not fun.

    nice post but I woul mention that if you use mosquito repellent please try to get Just wanted to warn people 😉

    I work with the Aberdeen Area Indian Health Service in the midwestern United States Several of our practicing physicians at some of our facilities are from and have received their medical licensing from Peurto Rico, thus they need to arrange to receive Dengue training by 2013 or risk losing their license. For most of these physicians, travel is restrictive, primarily due to staff shortages at the facilities at which they serve. There absence would create a hardship on the community.
    Is there any type of on-line training (webex) or similar that has been or is being developed that these physicians could attend online to satisfy the PR Dengue Training requirement. Thanks in advance for your help….and great article by the way…. If you could direct any responses to my e-mail address, that would be great…..Ahhhhh ! There is nothing like the smell of DEET in the morning.

    The dengue disease is caused by the mosquito. Aedes aegypti is one of the only few type of mosquitoes that spread dengue disease. Aedes mosquitoes are visually distinctive because they have noticeable black and white markings on their body and legs. Unlike most other mosquitoes, they are active and bite only during the daytime. The peak biting periods are early in the morning and in the evening before dusk. If we do a pest control then we can avoid all this diseases. Symptoms for the dengue Severe headaches, Pain behind the eyes,
    Severe joint and muscle pain, Nausea and Vomiting

    Unlike most other mosquitoes, they are active and bite only during the daytime. The peak biting periods are early in the morning and in the evening before dusk.

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Page last reviewed: August 22, 2011
Page last updated: August 22, 2011